Engine/Transmission (1994 - 1998) 97 Auto problems

[dpuckett]

My girlfriend works at an automotive shop in town, and I got a phone call yesterday while I was installing windows in my grandparents' new house.



They got in a 97 3500 4x4 auto ~250K, original transmission as far as we know. Problem is that when it's cold (sitting 4-8 hrs or overnight), it is REAL sluggish- seems to not want to transfer power to the wheels. After a mile or two, it is just fine. Fuel pressure is within spec, peak boost is 19psi. The shop owner took it out for a drive, and said he thinks it's in the injector pump- it wont rev up real high, and is kinda slow. (But, with a stock auto, and the fact it is having troubles cold, it makes sense to me that it's slow). No numbers on when it defules- I've seen here anywhere from 21-2500 as the max in a stock P7100 with an auto. The tech working on it thinks possible transmission issue, and based on my Mopar diesel transmission experience, I agree. Fluid looks and smells good, but I found with my mom's 92, the transmission can still be worn out, and the fluid be good.



The only real issue I can think of offhand with the pump (I'm better with VEs) would be the overflow valve, but wouldnt that affect it hot AND cold? Customer says once it warms up, it's just fine. It's my understanding that the P7100 is pretty reliable, and rugged, though a bad batch of fuel can wreck any fuel system.



I did find in a search some people who had SOME SIMILAR symptoms, but not all the same ones, and it was a seal inside the transmission. Which leads me back to the stock original transmission needing rebuilt at 250K. As far as I know, no heavy towing, but it is a work truck. I dont think it's a company truck, so only one or two drivers who dont hot rod it (not that that's possible at the moment, apparently).



What do you guys think? Besides that one of the best shops in the area calls me for advice on older Cummins Dodge trucks. :-laf



Daniel

 

[Joe G.]

I'm not sure if I understand your question. But, if it is sluggish getting going and gets better in a short time it may be normal torque converter overnight drain. Start it and let it idle in N for a little bit before going and see what happens. P won't work.

 

[dpuckett]

Update

I drove the truck, and noticed right off that it cranked about 2-4 seconds. I took it for a drive, and it shifted and drove alright. It doesnt like to drop out of OD when you floor it at 55mph (3. 54 gears), which makes me think either TPS or just age and miles. Didnt experience the lag in going when I took off, but I wasnt the first to drive it today.



I think it drove ok for a stock truck with the years and miles, maybe even a little zippy. The transmission is getting tired, which is expected, but it has some life left yet.



I DID find a pinhole in the supply line going to the lift pump, which could explain the long crank time. Or it could be the overflow valve. I started it 5-6 times in a row, and the same result each time.



I'm going to see about taking it home tonight and checking it out first thing in the morning.



Joe G, after re-reading my original post, I wasnt real clear in my question- What should I look at to fix the sluggishness first thing in the morning? I have found a couple avenues to look into. I wasnt sure if the 47REs had the same convertor setup/ no flow in P as the old 518s or not.



DP

 

[Joe G.]

First of all, a P7100 pump equipped engine will never start as quick as your VE pump. Just the nature of the beast. I'm told it has something to do with the governor in the pump. A little bit of pedal will start it quicker than no pedal, but still not as quick as your 1st gen trucks.

All stock torque flite transmissions that I have driven are the same way about TC drain and no filling it in P. I have a modified VP on my 47RH so it will work in P. A little bit of idle for the first start of the day takes care of it.

The kick down may not be because of the TPS. You may want to adjust the TV cable and see it that helps. Actually, if the thing is stock you may not want it to kick down. That results in the engine RPM being off the torque curve so you may just get more noise and not much increase in speed. The TPS is not exactly reliable on these trucks so you may be right about it being at least part of the problem.

If you want to know the details about how a P7100 fuel system works and how to fix it email me at -- email address removed -- for my write up.

 

[dpuckett]

On the transmission shifting-



Going through 1-3, it hangs at whatever RPM it gets to and stays there (the more pedal, the higher RPM), no drop at all between gears, much like my mom's 92. Get into OD, and it drops the RPM a little, then drops 800 RPM when the TC locks up. Then, say I'm cruising at 55 or so (~1500rpm), and want to pass on a hill. I have to hit the button on the dash to get it to drop into 3rd (in 3rd, it will pull to 65 mph just fine, so 50-55 isnt too much to ask). But, like you said, that is a minor issue, and easily fixed. Could just be a symptom of a bigger issue.



I'll have to look a little harder to find the TV cable. Certainly not as much room in there as my 1stGen. Is it a cable like the old ones, or is there a linkage and rod? I saw a linkage going to what looked like a rod, but I didnt pursue it past that.



Thanks for the suggestions,

DP

 

[Joe G.]

There are three cables on the throttle linkage mess on the near the front of the engine. The lower one which is pulled forward is the TV cable. It goes to a bracket behind the shift lever on the transmission. From there the cable goes to the TV lever which is just above the shift lever. There is a spring from that forward to the bell housing the pulls the TV lever to idle position. At full throttle the TV lever should have very little motion left if any. Less than 1/8". That's the base adjustment. You can change that adjustment where the TV cable attaches to the throttle linkage. The adjustment is part of the outer cable mount. You really need a service manual for stuff like this because it is hard to explain without pictures. Your '97 is different than my '95 on how the adjustment works so I can't take a picture of mine to help.