Greetings,

it's been a while... back to my offroad projects now... looking for some assistance... I know how to search and plan on searching as much as I can... But I have very limited time and would greatly appreciate if someone could point me in the right direction at least on some of my questions...

I currently have a 1993 Suburban, it is already SAS on 37's and has a 1st-gen Cummins with 47RH Auto on switches... I just picked up another 1st-gen 1990 Dodge Cummins Intercooled with a 5-speed... naturally, the manual tranny is going to go into the Burban, then the RAM will become an Automatic and whatever...

At the same time, I would like to address ALL common issues while the powertrain is out: KDP, 5th gear nut, new clutch and flexplate, rear main, all seals, SAS bracing, anything else that could be suggested...

I've posted on a couple of other forums, but the more opinions the better, as long as it's constructive and/or useful info... Cutting, welding, or any manufacturing is not a problem... Probably won't need adaptors... Just need some additional information...

1) Given that my Suburban is a 1993, what years of trucks should I look for to get the Pedals (clutch + brake), the Master and Slave Cylinders, etc?

2) Any words of wisdom from anyone who's converted an Auto Chevy to a Manual? I know I am likely to need to change driveshaft lengths... What else am I not thinking of?

3) As far as the SAS, first, truck came already with it done by the previous owner, it sags a little on the back, I was hoping to find info about what springs are commonly used for SAS'ed 90's Chevys... I remember it's older GM springs on the front now, but don't have specifics... The Suburban currently has front springs that were stock rear on an older truck and I think maybe a 2-4 lift springs in the rear? How could I lift it up a bit more in the front and then level out the rear? What's a good reliable brand for lift springs? Do I want air bags on rear? Not towing nothing heavy with this rig, just an offroad toy and an expedition rig, so gotta have good manners on AND off the road...

4) I've heard a few things about SAS rigs twisting frames because they were not designed for it... a suggestion was to brace the shackles and box the frame... any more info? how significant of a problem is it? Don't want to over-do it, but also don't want to break anything while I am out in the boonies, so?

5) I need to decide which of the 2 motors is in a better condition... How could I best compare them??? Both are 1990, rotary pump, approximately 200K miles, unknown for sure on both, both run well, the automatic one recently developed low oil pressure when hot, both smoke a bit on startup and clear up fast, what can I do to determine which block is best? Numbers? Oil samples? Testing?

6) Heard a lot about KDP and never looked into it and wouldn't mind addressing that while the powertrain is out... Anything else to do while in there? Preventative maintenance?

7) Will be putting in triple-disc clutch and flexplate that I already have and doing the Rear Main Seal at the same time... Anything else comes to mind since the motor and tranny are going to be out? Will look at all gaskets and replace as necessary... what else?

8) Also heard about the "5th gear nut" in p-pump trucks with NV4500, but is that also an issue with Getrag tranny that I probably have? I am mostly familiar with the NV line and not sure what else the Getrag might need as far as performance stuff... Ideas?

9) the turbo wastegate is welded closed (on the 5spd RAM), how much of an issue is it really, also are there any upgrades available for wastegates? I still need to determine which Turbo's I have in both rigs (they are Holset's)... Not planning on doing anything crazy, like composite, but would like to get all power I can from what I have...

I am open to all other reasonable suggestions and ideas : )

 

Here's several threads from thetruckstop(dot)us , due to time constraints on my part I didn't read very much of these threads, only enough to confirm they were apparently on topic. There may be other pertinent info in each thread also.

The first is a swap to a cummins.

http://www(dot)thetruckstop(dot)us/f...ns-swap.33394/

This has info about GM clutches, slaves, and masters.

Clutch master cylinder | The Truck Stop

This thread has info about solid axle swaps. In post 2 there is a link to another thread about a solid axle swap. This particular poster is very **** about everything he does, so although I never checked it out you may very likely find good info there also.

http://www(dot)thetruckstop(dot)us/f...le-swap.28886/

I hope these threads help you. For more info just go to thetruckstop web site and search as I think you may find more good info.

Don

 

Thank you!

 

1. Use the clutch master cylinder from the Dodge or get new if wore out. Should be easy to mount in firewall you'll just need to fabricate a longer pushrod. Find a complete pedal assembly from a Chevy standard truck of same year. The holes will not be in your firewall but there should be dimples.

2. I had to lengthen my driveshaft 5" when I did the same thing. Depending on where your engine mounts landed on the frame take note of where the shifter will come through floor.

3. Wait till you get the trans mounted before you try and change ride height. If the rear is sagging less than or up to a 1" use the DIY4x add a inch blocks in rear. Otherwise add overloads or more leafs.

4. On a 1/2 ton frame it is recommended to box it.

5. Adjust the valve and do a compression test. Have all of the injectors tested for leakage and flow.

6. KDP and new seals and gaskets. Install an intercooler.

9. Should not be a problem just affect fuel mileage a little.

Nice rig and good luck. B

 

That's awesome info, much appreciated, thanks!

 

The Getrag doesnt have the 5th gear nut issue, but you need to overfill it a quart so the front main bearing doesnt get starved going uphill. I put a 90* pipe elbow in the fill plug hole and pointed it upwards and it gives it approximately a quart more.

 

OK, time to update this thread, I’ve been digging on the internets and found some answers. I am guessing that my initial post was too long for most to digest. But I thank those who’ve replied here and sent me messages. Actually, when I first posted this thread, I was ready to start tearing things up, but then life happened, so both rigs are still fully intact…

This reply is even longer, so read on at your own risk, lotsa info… (and still need more)

PART 1:

1) ABOUT CLUTCH CYLINDERS AND PEDALS: Spoke with Peter from SouthBend Clutch (800.988.4345), they make performance ones, he is a dealer-support person on Cummins Forum (that forum is totally infected with ad-based viruses). Although my 13” clutch is made by their competitor, Velair, he still was glad to help me. Peter advised the Master + Slave that I have now in the Dodge are actually “upgraded” ones with their own brand. They market them as “performance” for 98+ models, but for my 1990 the only difference is the braided hydraulic line, both master and slave are pretty much stock for my rig (they are actually an “upgrade” only for later-model trucks that have smaller cylinders).

They do have 2 different brackets that this upgraded Master could bolt into, however, he advised simply going with a Chevy Master Cylinder– it has something to do with pedal angles that are very important – and ChevyMaster Cylinders are attached right to the pedal. The steering column MAY need to be removed to get the pedal bracket out of donor truck. The dealer can sell the entire 3-pedal assembly with a bracket, so I am assuming it could be found in a wreck yard.

There is an EXCELLENT and very detailed site with all diagrams (!), photos of different pedals and a LOT more info about swapping G56trannys (similar to my Getrag) into a Chevy truck here - http://www.gmtruckcentral.com/articles/t56.html - and they have to say the following:

"There is a lot of confusion around the clutch pedal bracket. From what I can gather there are 2 main clutch pedal brackets, onefrom 88-94(95), and one from 96+. However there is some grey area with them. 1995 apparently was SUPPOSED to be the changing year to the new design. However I have owned both a 1992 pedal bracket as well as a 1995 one. They were identical. There is also someone I have talked with who did the swap on a 1999 GMT400 truck, and the early pedal bracket style from a 1995 would not fit on his 1999, and he was required to get a newer pedal bracket from a 1998 for it to fit. Yet in my 1996, I currently use a pedal bracket from 1992 which works perfectly. So the best I can figure is that the 1995 and 1996 years were transitional years. Some likely used the old bracket, some the new. Unfortunately, for those years it may be hard to know what will work and what won’t. Let me just say that the earlier bracket style is easier to find and I did not have any problems installing one in my 1996. There are also some other unknown brackets out there.”

To match a Chevy Master Cylinder to the right-sized Slave, I would need a Slave from 1994-1997 Jeep Wrangler 4.0L (possibly a Grand Cherokee 4.0L) because it is a smaller diameter and is known to work well with Chevy Master. I will get that Slave brand new at a parts store. I will also need to get some high quality hydraulic line, as I keep hearing everywhere that these trannys are a bear to bleed. Peter was busy, but he briefly advised to do installation dry, fill with fluid, release some clips, connect to slave so there is no air. The bleeding procedure involves pushing on the Slave’s Rod 15x times slowly to let the gravity bleed out the air. May need to adjust the rodlength too. Dodge recommends buying a complete sealed kit and not having tobleed it. But that is not an option for swaps like mine…

Here’s some numbers I found:

The slave cylinder is the same for all years of Cummins trucks. The only difference is the push rod length. A Getrag 5-spd and a NV4500 to around 2002 use a push rod that is 5.5" long. The NV5600 and G56's usea 6.5" pushrod. Master cylinders all have the same bore size. The only difference is the rod from the pedal to Master Cylinder. A 1st gen (1989-1993) uses a push rod that is 1.375" shorter than the 2nd gen (1994-1998) and later (1999+) Master Cylinders. The bore size is the same on all Master Cylinders. A 1st gen M/C push rod measures 4. 875" from end of M/C tocenter of the eyelet. A 2nd gen and newer is 1.375" longer than a 1st gen M/C.

But all of the above info is going to be moot if we go with Chevy pedals + Master and the Wrangler 4.0L Slave… Another thing to keep in mind is the need for HydroBoost – my Suburban currently has HydroBoost already swapped in for its current 12-valve, but the stock RAM truck actually has vacuum booster brakes… Surprisingly enough, here on the West Coast, there are absolutely no wrecked Chevy trucks with the complete pedal setup – the only one I found was in Idaho… Then I found just the clutch pedal with master here locally… May need to cut down my existing automatic brake pedal if I don’t find the correct one...

2) Currently, I have a 12-valve with 47RH auto and NP208, which is driver’s side drop from a newer rig… The RAM truck has a 12-valve with Getrag and NP205, which is passenger side drop, stock… RAM currently has KingPin Dana 60F front and Dana 70 rear… Suburban currently has Ford HP44 front and 14-bolt rear… hmmm…

The AUTO tranny & tcase are 23 spline input shaft, but the 5-SPD tranny & tcase are 27 spline... So the tcases will NOT swap from Auto to Manual... hmmm… Looked into mounting the 205 upside down, rock bouncers have done it with divorced units, but still have fluid leaks through shift linkage though...

So, it looks like I will be swapping the axles together with the powertrain, why not upgrade to 1-tons??? According to the internets, all 3/4-ton 1st Gen Dodge Cummins trucks came stock with Dana-70 rear axle and Dana-60 front... To tell for sure, the "60" is cast (not stamped) onto the housing, on lower driver's side corner next to the cover of axle housing... There also is supposed to be a sticker under the hood that would state the axles AND gear ratio (stock)... Note that there are 2 varieties of D60 front – rated at 3600 and 4500 lbs - they use different unit bearings and brakes...

 

PART 2:

3) I've also looked into leaf spring options, it seems that for SAS (solid axle swap) they've used a 73-87 Chevy springs, either Front(47") or Rear 1/2 ton (52")... and it should be a 32" spring pad width (center-to-center)... I still haven’t had the time to measure, as suspension will be one of the last parts to do, but still would be good to get an idea and start looking for parts… not liking an idea of any blocks… but overloads or lift springs might work once I know their exact size…

4) I recently found out that the GMT400-platform rigs(91-up), the ones with IFS 4x4, have skinnier frame than the older rigs… Not to mention they were not designed to have leaf springs welded onto the front… so, some cross-bracing and boxing should be done, still trying to decide how crazy to go here... at least around the leaf spring mounts...

5) As for comparing the 2 blocks to find a better one, obviously the compression check is the best way, I knew that, just don’t really want to mess with taking out the injectors… Is it something that is STRONGLY recommended? Looking at the two blocks, the motor in the RAM has had definitely some work done to it and seems to be more solid, will check it out some more when pulled… Will get the front cover done, pull the oil pan and see what’s in there, maybe do the valves too…

6) yes, the KDP will be done, along with loctiting all cover bolts, read plenty about it, applicable to all 12-valves, 1st gen and 2nd gen had different “kits”, as they use different front cover gaskets, but nowadays everyone just says to use RTV silicone – and that’s what Cummins recommends too… The kit is around $60 if I don’t end up making that tab myself… Also found out that all gaskets and seals can be had from either NAPA (FelPro) or CumminsNW (stock) within a day if I don’t end up ordering them…

7) Still interested in learning what others would do to the block and tranny while they are out of the rig… I will look at front cover and oil cover and rear main… will check the thrust bearing too (learned recently they CAN be a problem)… anything else???

8) The 5th gear nut does not apply to Getrag and so that’s not something I need to worry about… And, yes, I've read about overfilling them a quart... now, what’s the best way to open up the tranny and check it, is it looking for obvious stuff or something specialized?

9) I still need to verify why the previous owner claimed a welded wastegate… the turbo has been upgraded to a newer one to accommodate intercooling… but I think that 12-valve rigs do NOT have a wastegate all together??? Now, I am not sure what model turbo I have swapped in, as it was rebuilt and painted and the sticker is gone… but there sure doesn’t seem to be a wastegate at all… Seems like that is not an issue…

So…

Those were some of the answers that I found, in case if it’s useful for anyone else… I am now actually thinking about leaving my Suburban that’s done already alone and building a new one… Not decided any more, just came up with the idea yesterday, might be the easier way to go and better trading stock this way… But both Suburbans and Long-bed Reg-cab RAM are130-inch wheelbase… welding on body mounts is not that hard… but that’s just an idea and I still might continue just swapping parts between the two rigs as described in this thread…

P.S. – my next project, when this one is done, might be combining my 2004 LB7 with 4x4 Allison (that had a tree fall on it during as now storm) with my current daily driver 2004 ESV Platinum Edition, not many Duralades like that are out there, but that is an ENTIRELY different conversation and completely off topic for this thread

 

So, I got distracted on other projects and medical issues for a bit, but back onto building up the Suburbins again now... I think I will use this forum for my build thread and writing down the info that I've been gathering... maybe someone will find it useful some day... I have very limited time, so forgive my short hand writing, it's the info that matters...

Spent a few hours last night looking a the axles... Did a bit of research on the internets about Dana 70 Rear vs 14 bolt... both rigs that I have seem to use 4.10 gears... the Dodge truck has a positrack D70 in it and the Suburban has an open 14B, but gear ratios seem to be the same... I was initially thinking about keeping the Chevy 14B in rear and swapping the Dodge D60 in front, but based on the below info, I recon that I better use both Dodge axles...

My rear D70 was rebuilt by previous owner about 10K miles ago, so that's a strong point, although there is much discussion on the internet about making sure that it's done right, because bearings are shimmed to deliver a preload on the bearing, this preload is set by resulting drag required to turn the shaft, also the backlash needs to be measured and set just right for it to preload correctly... I guess I will find out more when I pop the cover and look inside for any signs of shavings... But it's appealing that the rear diff was rebuilt recently... also learned how to tell D60 from D70 rear by looking at the cover (both use same covers), if the axle goes right around the cover, it is 60, if it has more beef around the cover, then it's a 70, and mine is a 70...

I was wondering if my D70 is just posi or has a Detroit in it, looked online, learned that Detroit would make a "ratcheting" or "clicking" sound... the general consensus on the internets is that 14B is a little stronger (better pinion) and easier to find parts for locally, but has limited gear selections... Dana axles have more gear and locker options available aftermarket... to me both D70 and 14B pumpkins look about the same, size-wise... I realize that there is a difference in the pinions and other internals...

Confirmed on youtube (https://www.youtube.com/watch?v=RNgjS5mHI0E) how to determine gear ratio without taking the wheels off... basically, tape up the driveshaft, leaving a bit of tape as a "flag" sticking up, then tape up a wheel to mark the spot to track one full rotation... then turn the wheel 10 times and count the amount of revolutions of the driveshaft... I used 10 rocks to keep track of wheel rotations, while counting driveshaft rotations in my head, since I was alone... with locked differentials (or posi), both wheels spin the same direction, then it's just dividing the number of driveshaft rotations by 10... so if it rotates 41 times, you've got 4.10 gears... with open differential, the wheels will spin in different directions, one wheel needs to be blocked, the number of driveshaft rotations will need to be multiplied by 2 first, then divided by 10, also without posi, one wheel needs to be propped to prevent it from moving and screwing up the count...

meanwhile, I also had a chance to learn a few things about Dana-60 front axles... the Dodge has leaf pads on the axle about 1/2 inch to 1 inch wider than a Chevy axle... it was a bit of a concern at first... but it sounds like, as long as the truck has lifted springs, with at least 4" lift, "spreading" them 1/2 inch on each side shouldn't be much of an issue, but there are several other solutions too... front perches could be rewelded - and since my truck's front perches are custom made for SAS anyway, that also might be an option - kinda similar to how Dodge's springs are not mounted perfectly parallel to each other (2 inches narrower on the front compared to rear mount)... and using different bolts and spacer washers is another option... and there also are aftermarket "offset" shackles available (nice option)... wheel stud width is another thing to watch out for, as well as "external hubs", which are supposed to be weaker (but it sounds that 90-93 are internal and Chevy hubs will also bolt right in)... btw, Dodge axles are about 2" narrower than Chevy axles in overall width...

It's starting to look that I will be putting both of the Dodge's axles under my Suburbins... did some measurements yesterday, will need a different crossover steering kit for Dodge D60 front, as D44 that is currently in the Suburban has 3-bolt mount, instead of the 4-bolt mount... there are kits that relocate the tab to point forward instead of to the side, which also allows to take care of shocks... yes, the shocks are wider by 1 inch on each side on the Chevy compared to Dodge... Dodge currently has them mounted behind the axle, but with this crossover kit I can reweld them on top of the axle...

last, but NOT least, here is the DANA 60 BIBLE with TONS of useful info:
Pirate4x4.Com - Extreme Four Wheel Drive

Have been learning about drum vs disc rear brakes... general consensus is that drums get clogged up with mud and sand easier and wear out a lot quicker... upgrading drims to 1-ton wheel cylinders helps with stopping power... but discs are worse for dusty roads... also, apparently it's quite hard to find a kit for Dodge D70 disc brake conversion, unlike the Chevy 14B that simply uses 80's chevy front calipers and rotors... but there are some weld-on solutions that I am researching and will post up some info once I confirm the best approach... I would prefer to be able to run stock rotors and calipers, while most "kits" out there use custom made ones... the best one I found thus far is by Products | Lugnut 4x4 | Disc Brake Conversion Kits for Dana 60, 70, 80, 14 bolt and Sterling 10.25, but I suppose there might be other options, just need to find them... to be continued...

 

OK, so I’m just making some notes… Might be useful for someone some day… Feel free to skip over this if it doesn’t interest you and eventually I will post up some photos to look at… I know, still no pix, so it’s all just long-winded reading for those who may be interested… One update is that I got rid of my original 1993 Cummins Suburban… Attempted to start working on an 85 factory Manual Burban, took me forever to find a rust-free one and got as far as taking it off the frame, but it fell off a trailer on the freeway on the way to get sandblasted and ended up needing fixed back up (for sale now)… So now I am working with another black 1992 Suburban 1500 body… For some reason GMT400 and GMT800 bodies don’t seem to get quite as rusty as the older ones…Although more clear coat peel on the early 90’s ones…



Started looking for frame diagrams to get the measurements for body mounts and figure out how to box and reinforce the frame. I do have AllData 50-DVD collection at home and can’t get it to work after reimaging the system recently. I will someday... But getting close to start welding things… So, for now, had to look for diagrams online. Found some body manuals for 1999+ Chevy trucks and Suburbans on gmupfitter.com website, then came across a link to the earlier C/K bodies (GMT400 platform) hiding on the same website (http://www.gmupfitter.com/files/medi...uckCurrent.PDF). Then, someone on RamchargerCentral.com was nice enough to post a link to the1990 Dodge W250 frame specs (http://smg.photobucket.com/user/ramc...1guse.png.html). Also, found a pretty detailed thread with tons of photos of someone doing a similar older Suburban body onto Dodge frame swap (http://67-72chevytrucks.com/vboard/showthread.php?t=411609) – good read.



Did a lot of thinking about the best way of setting up the manual swap pedals and doing a hydroboost conversion at the same time. For pedals, any 1988-1994 manual pedals will work. Clutch pedal bracket is separate and just bolts onto the firewall in the stock location. Still thinking of using stock Chevy master with a 94-97 Wrangler slave (unless I can figure out how touse the aftermarket Dodge ones already in the truck now). Brake pedal mounts to the firewall, the mounting method is the same for Auto vs Manual pedals, just a bolt that screws into a welded-on nut. There is, however, a difference in brakepedals between Hydro-boosted and Vacuum- boosted trucks – the difference is that the bar for master cylinder rod is about 1-inch higher on the Hydroboosted pedal vs Vacuum one – otherwise they are identical (and cutting down an Automatic pedal works too). Some pedals actually have dual holes, but it would be easy enough to drill a hole and remount the rod bar if needed, although I just searched all over and managed to find the only set of original hydroboost manual pedals in the Northwest (came from a diesel truck together with a hydroboostunit and a gauge cluster). Still looking for a steering column out of a Manual Tranny truck of 92-94 vintage. Might just end up cutting the shifter stick off mine for now and calling it a day.



Also learned through various threads that I will need tomove my 4x4 steering box into the 2WD spot to have proper crossover steering, the frame will need plated in that spot, and all leaf-spring shackles will need upgraded bushings. Most problems seem to stem not from the frame itself twisting, but from the straight crossmembers flexing, so thinking about x-reinforcements. Still looking for more information on where to put X-reinforcement on the frame and how to do it without compromising the factory-designed abilities. Don’t want to move stress-points to less-desirable locations. Also still looking for comparisons between two types of lockers, the full carrier replacement ones, or the lunchbox style ones. Rear axle is posi and I probably will leave it that way for now, but front is wide open, so it needs something to get proper traction.



The hydroboost units differ across the years, but all are similar and seem to interexchange, they initially came loaded with nitrogen and then switched to a more reliable spring between the booster and the master cylinder. Newer trucks are setup for rear disc brakes. I am keeping rear drums for now (with 1-ton wheel cylinder upgrade), so I got a setup that cross-references to fit a 1992 body (only 92-93 units fit). Lots of people go with 1999-2002 and 2003-up units, or even smaller ones from an Astro van, I just chose this one because it would be a direct swap with nothing to modify and I actually found the correct one. The lines go high-pressure from the pump into the hydroboost, then into power steering, then both low-pressure return lines (from booster and steering) can T-together and go into a cooler and then back into the pump reservoir. Also picked up the diesel gauge cluster from the same donor truck at the yard, it even has a factory tach, if I can only figure out the best way to wire the tach onto my 1990 cummins. And did some research on hooking up the speedometer, apparently it uses a DRAC module, which is a little white box behind the glovebox, it takes the signal from VSS (such as on the NP205 tailshaftof my Dodge) and converts it into a signal for PCM and for gauge cluster. The DRAC module can be modified with some 7-pole switches to be infinitely adjustable for tire sizes and gear ratios. So that’s another project to add to the “electrical” list for later.



Also did a lot of research about bedlining my rig. Obviously, Line-X is the best option, but I called around and everyone wants $2500-3000 to do the exterior of my Suburban (including prep time and hot pressure-spray). I still want to also do the frame and inside of the engine compartment and don’t have crazy money for paint. So looked into DIY options. Always liked Aluthane before, but it’s not quite as durable or scratch-resistant as I would like for an expedition rig, although it would make one fine primer and rust inhibitor. Herculiner and other cheap alternatives are just that, cheap, low quality. Might as well use Rustoleum spray cans then. But there is another option – Magnet Paints – Monstaliner. It comes closest to hot-sprayed liners in thickness and finish, very durable, plus not too hard to wash the mud out of (compared to some other liners). Jeep crowd goes crazy about it and they even have their own special on the jeepforum (free shipping and free can of chassis saver). I need about twice as much as a Wrangler would, so I ordered one special and had a buddy order another special, shamelessly using thejeepforum discounts and saving $130 in the end. Got 4 gallons of Monstaliner on the way, two quarts of 2K Primer, and two quarts of the Chassis Saver. That Chassis Saver is very similar to POR-15, but better, perfect for frame and suspension parts. All of it can be brushed, rolled, or sprayed on. They also sell Italian Shultz guns that are perfect for bed liner application and provide even spray at 60psi with a regulator set to 80psi on a 130psi 20-gal air tank.


Getting closer to actually starting wrenching. Kinda tired of doing research and just collecting parts. Although learned a ton. They say, the greatest reward for our efforts is not necessarily what you get for them, but what you become by them… And it’s nice to have all the ducks in a row with projects like that because I don’t have an unlimited shop time...