hi. my truck started doing this yesterday. immediately after braking hard to avoid another car, the engine started revving and barely going anywhere. so i slowly crawled to a stop. even in Drive, it wouldnt move. i turned her off and tried again. it then drove for about 2 miles and then just started revving and going nowhere. i was able to get it home at about 20mph. this morning, it started fine and drove normally for about 3 miles and then started with the same revving issue. is my tranny ok? is it time to start thinking of getting another truck? she's got almost 230k. thx everyone.
95 jimmy engine revving
- Thread starter BAD SVT
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Molson02536
New member
Before guessing at transmission problems, check the fluid level (car warmed up, engine running in Park on level ground) and have the PCM scanned for trouble codes FIRST.
You could have a pump failure, or total loss of fluid circulation. If low or out of fluid, avoid running the engine until the trans is refilled to avoid pump damage. To check for pump failure, check fluid level with the engine off, then start the engine and recheck fluid level. If level does not go down when engine is running, the pump
Poor line pressure rise due to leaking boost valve, clogged EPC filter screen, failing EPC solenoid, or worst case: leaky seals throughout. Transgo HD2-C kit fixes first two without removing trans. Seal restorer may fix last problem, but probably R&R.
Send me a PM, on tour right now and should be back home wed night. Good luck and keep us posted. Put a line pressure gauge (or visit a local trans shop) on the pressure test port and go for a drive to verify proper line pressure. Base pressure at idle in P,N,OD should be around 70psi and around 140psi in R. Max line pressure should be at least 190psi at WOT in 1st or 2nd, 225psi is optimum. If base pressure is low, trans or pump is worn out. If max pressure is low, check EPC solenoid. If reverse is slow to engage, and line pressure does not come up to at least 130psi in reverse, replace the boost valve with a Transgo 0.490" boost valve (easy fix in pan).
thx man. i appreciate the help. i noticed u've helped out a lotta ppl on here. great to have someone like u on the boards. thx again. i'll get on it tomorrow. and i did actually check the fluid level. it was full. no tranny leaks either.
i couldve sworn i posted sumthn right below yours yesterday... anyway, i went with ur suggestions and checked the oil level. it was high this morning b4 startup. when i started it, the level dropped. so i guess the pump checks out. the other stuff i'll just have the tranny shop do, as i know little about trannies. i'll just pay for the hour to tell me what's wrong. and in case i didnt mention, there is no CEL. pending codes maybe...
oh snap. the reply quote function doesnt work. thx for the suggestions man. i followed them and did the oil check. it was full this morning b4 startup. when i started it, the level dropped. so i'm guessing the pump checks out. as for the others, i'll just have a shop do them as i know little about gmcs and trannies in general. and i forgot to mention; there is no CEL. and cuz its OBD1, there doesnt seem to be a shop that wants to scan the code for free, so i'll have to pay for an hour diag.
so i took it to a shop. they're charging $1100 to fix it. no shop is gonna touch it without pulling apart the tranny. its gonna have to be rebuilt. they said they'll tell me what they're replacing as they go. is that about right?
Molson02536
New member
From what you have described on what happened to cause your transmission issues. I'm leaning towards No TCC lockup: Brake pedal switches improperly adjusted (always on), TCC solenoid failed (easy fix in the pan), TCC clutch worn out (must remove trans and replace TC). TCC (Torque Converter Clutch)
See if you can get your Jimmy scanned for a DTC code and also check all your fuses. Post me back, be glad to help you save some money. At worst, i'll buy your Jimmy from you
i'll have them run a diag in the morning. they did pull the pan tho. they said it had a bunch of stuff in it that just looked like impurities to me. then again, i'm no pro. like i said b4, everytime i shut it off and started it again, it worked fine for another mile or so, then revs come back again, and the truck goes nowhere. and on my way to the shop, i heard a certain 'roar' coming from the tranny area.
Molson02536
New member
4L60-E transmission have numerous converter overheat and lock-up complaints related to valve bore wear. These include no lock-up or lock-up immediately after 2nd gear when fluid warms up. Frequently the solenoid will have no control over the valves position. These complaints are usually created by excessive pump bore to valve clearance. Often converter feed oil will leak past the OEM spool, which added together with orificed signal oil, will be more than the solenoid can exhaust. This may completely stroke the valve into the lock-up position and create a no power or no brake cancel condition. Oil cross leaks may float the valve into a midway position and restrict cooler flow, which burns up the converter.
Have a shop verify line pressure, and provided no valves in the TCC hydraulic circuit are worn, replace the torque converter. And a Poor line pressure rise due to leaking boost valve, clogged EPC filter screen, failing EPC solenoid, or worst case: leaky seals throughout. Transgo HD2-C kit fixes first two without removing trans if your Torque converter is good.
Keep me posted on your transmission and have then replace the boost valve to 0.490" since they have it apart.
