Ok so Ive owned this truck 10 years now and have had no problems whatsoever with shifting etc... the only prob I had was the injection pump... Now I just replaced the sending unit and replaced the lift pump. Its been a good while since Ive driven this truck so i dont remember the RPMS it runs at at 70 mph but seems very high to me... I want to say RPM is about 2500 at 70.. Is this normal or is it not shifting into overdrive.. When I bought the truck the steering column was replaced. Also recently after I shift into drive and drive for a minute then stop and shift into reverse it takes a bit of time to shift into reverse unless I tap on the shifter.. does that sound like something going on in the transmission?

Please someone help me on this. My dad is a disabled veteran that has fought in every war since vietnam and I gave this truck to him and he does NOT want to get rid of it and I am NOT going to let him drive something that is not going to be reliable!

So please someone help with this or give me some sort of idea to start looking at...

Ryan

 

Sounds about normal for 70 mph and 4:10 rear gearing. My 98 turns around 2200 with 4:10's at 60 mph on stock size tires. Overdrive and lockup work on mine, I monitor it through the OBDII connection in "real time". Torque peak on these engines is right around 2200 rpm (most efficient range). You're spinning another 10 MPH faster, so another 300 rpm is pretty good. Power requirement is exponential, not linear (for example: it might take 20 additional hp to go from 50-55, but 35 hp to jump from from 55-60) and the big power jump happens right around 55 mph due to aerodynamic drag.

I wouldn't worry about it too much. The 4L80E is all electronic. Meaning it "kind of decides for itself" when it shifts. There may be a small thing going on in your shift selector switch with wear or adjustment, hence the hesitation unless you tap the shifter. It does shift on it's own if you don't "tap it" and after all, it is 12 years old. It still doesn't sound like a big issue to me.

FYI, you're really only moving a switch selector with the gear shift lever on a 4L80E since it's essentially "fly by wire" like the throttle on a 6.5. Well, except for the park pawl cable...

The truck sounds fine to me from what you've given here.

It's going to be as reliable as any other 12 year old rig with whatever amount of miles are on it.

How he intendeds to use it changes things up a bit though.

There are some "upgrades" that are worthwhile if he intends to tow long or heavy with it (IE: cooling, reliability, power, etc). See my sig pic for an idea of what I mean.

But if he's just going to drive it around town and pick up some stuff at the local building store or a load of dirt now and then about all I would suggest is changing out the fluids and chucking a spare PMD in the glove box. Then just keep up on the maintenance and keep an eye on it like you would any other vehicle.

That's from a fellow "brother in arms".....

 

my truck does 2500 @ 70mph too. no big deal,

as far as the shifter x2 w/ great white, there could be a loose wire in the column or the cable could be close to replacing, or the switch could be losing its integrity

 

Awsome answers guys greatly appreciate it! I used the truck before hurricane katrina to pull a 6x12 inclosed trailer installing floors but ever since then it mostly sits until my dad drives it places. He loves that truck!
I drove it to autozone to get a transmission cooler for his transam and when I got in the parking lot and went to park I stopped 3ish feet from the curb and went to pull up till I bump it and it was out of gear? Let go of the throttle and then accelerated again and it was fine..

This cable your talking about does it go to the transmission from the column?

 

Yup. But all it does it engage/disengage the parking pawl.


Sent from my iPhone using Tapatalk

 

Great White you know more than I do WAY more and my question now is, I just replaced the fuel sending unit and the one I replaced it with is from advanced auto parts.
Before I started haveing the issue of my fuel gauge bounceing all over the place when the fuel level lowered to about 3/4 of a tank, my fuel gauge worked completely fine didnt bounce all over the place or anything, it gave me a constant level.

So I replaced the fuel sending unit and filled the tank completely. I just reached 80 miles on the tank and the fuel gauge level has gone down to the full marker ( not past it like topped off) and while running, the gauge is fine unless I hit a series of bumps or going up hill or down hill or stopping and going. When I hit these bumps or etc the gauge bounces almost like it did before! Just not as bad...

When I picked up the new sending unit the box was half crushed!
The sending unit looked fine to me so I went ahead and installed it and it read correctly on a empty tank after I added 3 gallons to the empty tank the gauge went up some (but still moved some on the way to shell to fill up..)..

Please tell me this is normal or do you think I might be missing a spring on the sending unit or possibly the wrong sending unit? Or maybe a bad sending unit?

Whatever the case is, I dont like this fuel tank doing this due to the fact my dad is going to be using it most of the time AND due to agent orange from vietnam he has just recovered from kemo and radiation from cancer and he has a muscle disease called IBM that causes him from reproducing his muscles soo when its gone its gone!
The V/A has listed him as 100% disabled

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That's from a fellow "brother in arms".....[/QUOTE]

Thank you for serving! REALLY appreciate that! My mom is also a retired masterchief as my dad, my brother is a pedi officer and my other brother is civilian employed in the air force doing programing on f-15s.
Its a good thing I didnt follow into the military like my family due to my father and his health issues and until recently I was the only one here to assist with their vehicle and home maintenance

 

I don't know way more, I just have a bit more experience...

For the full sender, maybe try this:

https://www.dieselbombers.com/chevy-...-van-6-5l.html

 

Any Ideas on where the buffer module is located?

 

For future I would try to stick to GM or AC Delco parts. Especially in electrical. You can save some money by googling the part numbers and searching them at Amazon.

There are some parts that are better aftermarket. The engine oil cooler lines for one. The GM lines suck. lubrication specialist out of Indiana. I'm pretty sure that's the name without looking.

pmdcable.com for a spare PMD, extension harness and heat sink.

pmdcable also has an aftermarket sending unit

If you have to replace the lift pump again use one listed for a 1993. They have slightly higher flow. And once again I've had better luck with Ac Delco's in lift pumps and OPS/ oil pressure switches/sending units.

 

Is the buffer module the module that has the wrong placment from factory and you have to extend it from I believe the rear of the motor to the front bumper or close to it?