Mercedes OM617 diesel to AW4 Cherokee automatic trans
 

Just got an AW4 transmission to make OM617 Mercedes diesel conversion some guys have been asking for. Got bellhousing to engine adapter back from shop today. The crankshaft adapter is the same as one we made for the wrangler automatic. Here is a progress so far.

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Hope to test fit to engine this weekend. :humm:

The AW4 is an electronically controlled tranny. In a Jeep it relies on inputs from the TPS and (I believe) the CPS to determine its shift points. So how are you going to provide or mimic those inputs?

we still have CPS in original location, hope to keep intact. If not we are looking at the RADesigns shift controller.

Doesn't it use the TPS as well? You going to try to adapt that somehow?

if it does we will adapt to TPS, the one we are worried about is if it reads RPM from distributor? If it does we will be forced into RADesign shifter.:humm:

IIRC it reads RPM from the CPS. It reads how far you put your foot in it from the TPS.
Thats really the only two things it needs to determine when to shift - how fast the engine's turning and how much throttle you're giving it...

Looking good! I'm glad to see progress on this! Keep it up! I look forward to hearing from you when mine's done! (First one of course!) Yes, this is Dean, the guy that called you monday and lit a fire under your...:moon:

As far as the transmission control, I can look up the wiring schematics on Mitchell On-Demand at work on monday. I told you about the little box with toggle switches I built for our Jeepspeed a few years ago, but talking with my wife, she prefers to maintain the fully automatic feature as well. So, I will be looking that up for my project anyway. Having manual control over the torque converter lock up may prove to be handy even with the TCM though...

So I did some research this morning, to keep the TCM happy all we need to do is mount the TPS. The TCM does not receive any signal from the CPS. The TCM has it's own speed signal coming from the transmission's output shaft. We couldn't ask for that to be much easier.:tu:

What year tranny & TCU are you using? I'm pretty sure that varies by year...

IIRC the 90 and earlier (ReNix) system uses the CPS for tach signal, because they have no VSS - the speedo is a mechanical drive off the tail housing of the tranny. The 91-96 ((HO) uses the VSS on the tranny tail housing, and I'm not sure what the 97-01 models use, but unless I'm mistaken they don't have a separate TCU - its functions are incorporated into the main ECU.

I looked it up for my '88. I can check the latter years tomorrow, I didn't even think to check them. There is an output shaft speed sensor in the aw4 specifically for the tcm. It has nothing to do with the speedometer. I didn't remember it was in there, if I were to have guessed I would have thought it needed the cps.

Guess my memory is faulty then...

The Jeep AW4 Transmissions - Novak Conversions

... little info that has lead me to this as well.

OM617 is a sweet motor, and the tranny would work great... Just need a lil bit of imagination! Congrats!

Subscribed by the way...:c:

Like I said, I was thinking the same thing... I dug a little deeper today and even the latter XJ's had a stand alone TCM/TCU with their own speed sensor inputs right from the transmission as well. In 1998 though, the TCM was also on the CCD bus so doing away with the engine computer on those would cause some issues.

You know who we haven't heard from this week though... jeep-dsl, how'd the trial fit-up go?

All the detailed info you could want in post #5 here
AW4 manual shift - JeepForum.com

I was close to having it right on which solenoid to power to shift it into each gear, and the TCU being incorporated into the main engine managment computer was in 98 - not 97 like I thought.

And in regards.resonse to the rather negative comments about the AW4 on the Novak site: it may not be up to hard service behind a built V8, but behind the 4.0 L inline six that Jeep mated them up to they are nearly bulletroof. The addition of a small secondary oil cooler makes them even more so. My 96 2-door 4-wheeler started life as a 2WD. I pulled the AW4 & transfer case out of my previous 4-wheeler - a 92 with 225k on the clock - and put them into the 96 to convert it to 4WD two years ago. Its still working just perfectly, and the last 5 or 6 years it has seen a lot of hard off-road miles.

The AW4 should hold up beautifully to the levels of horsepower and torque you can make with an OM617.

Several years ago I built a little box with 4 toggle switches to control the shifting in an AW4 we were using an a JeepSpeed rig. That's basically what that was talking about, it enabled us to run in second gear with the tcc locked which really helped with transmission temperatures! The driver later chose to go with one of the commercially available ones that was easier to use and it failed mid-race! It was easier to use than the one I built though. It looks like up until '98 model year though it won't be difficult at all to keep the TCM/TCU for fully automatic operation of the AW4, and that's a good thing!

I still want to hear from jeep-dsl...how's my adapter fitting?

I never went quite that far, but I did set up a nice little 1st-2nd shift lock rig. Simple 3 positon rocker that had a locked in 1st, locked in 2nd, and normal auto positions...

Shifting the AW4 into reverse is still done by a mechanical linkage, right?

BTW, where is Spokompton? :)

Yep, reverse is mechanical.

*warning: momentary thread derailment*

Spokompton? Well, it's also known as Spokan't by some people, or SpokaVegas. I enjoy Vegas too much to associate it with this place though. If you watch our news or read our paper lately you'll see we have more in common with Compton as of late. I never really like it here anyway and now it's getting worse. We were what? 3rd in the nation per capita for vehicle thefts. Just last week some lady's walking her dog in the morning and gets killed... It's a great place to be "from"...

*back to our regularly scheduled program*

HA! Come over here and live for a while in the People's Republic of King County. You'll be THRILLED to move back to Spokane...

Any news guys?

Plates are doneand fit great, dont know if it can shift yet without manual shift controller.

ever think of using a dodge sprinter engine with a zj tranny like in Europe

Aren't you using a TPS adapted to it, so you retain the TCU as it is?

Hi Jeep-dsl, thanks for doing the aw4. I had mailed you about it I guess a year ago. Are you doing anything for a pilot bushing for the nose of the torque converter to the MB crankshaft? Or am i missing something? I assume you are using the AW4 torque converter?. I hope to convert my '96 xj 2wd. If I buy your oil pan how much if any lift will I need

thanks

Bump
 

Did this build ever get finished?

I bought Jeep-dsl's adapter he started making and I did complete the swap. I made a bracket to hold the TPS sensor and the AW4 worked just fine. My engine, on the other hand, spun two rod bearings shortly after the install and I have not found a crankshaft for a reaonable price. When it first failed i was so disgusted with the whole thing I ripped it out and bolted an AMC 304 out of my CJ-5 to the AW4 and our little cherokee has never been more fun! (The CJ-5 got a 401!) I still have the OM617 and adapter if I can ever find a good crankshaft I'll put it together for something else, maybe. It could also be for sale. I'm still a fan of this idea and I would have kept the OM617 in there if the one I bought wasn't junk, it came from a wrecked car and I'm betting they ran it without oil after the front end collision killed the oil cooler.

Oh wow that sucks about the 617, I was hoping to find out how it did cruising on the highway, there's a slim chance I may know where a crank is I'll have to talk to a guy first though

Mine has 4:10's in the axles and 32" BFG's, It cruised at freeway speeds fine until it started tying up like a 2 stroke. I never got any mileage numbers out of it, didn't run long enough. It did move along ok though. Not fast, but adaquate, I wouldn't plan on towing much with it or anything like that. I'm interested in the crank if it's cost effective... mine would have to be machined .030 or .040 under and bearings aren't available. Machinists locally here are affraid to weld, regrind, and re-nitride it.

Towing is definitely not something I do with my Jeep ever since I had a bad experience towing with it, and I use to drive a 83 300D, those engines definitely ain't for speed, I just don't want to have to be revving it high to maintain a highway speed

Hey guys, a little personal experience here. I had an XJ with the OM617, was talked out of using the AW4 and going with the 700R4 because of the TCU. Big mistake, I had a love/hate with the Jeep mainly due to the 700R4. I always regretted not trying to keep the AW4. Sold said Jeep and later did another XJ but this time using a Kubota 2.2 along with the AW4, way better trans. Wish I could have gone with the AW4 with the first jeep, probably would have kept it. Once you get the TPS dialed in it's a SWEET trans. behind a diesel.

So you didn't use a stand alone trans controller?

I used the Jeep TCU, it's already stand alone in the early XJ's. You have to keep the Jeep flywheel and TPS, once you get the TPS dialed in it shifts like normal.