mcrandrz

Hi. I have a 1991 camaro rs 3.1 bone stock. I've got a problem with my transmission. It takes about 20 seconds ( sometimes never) to shift from park to drive. And it also ( I want to say) down shifts and throws the rpms really low while going anything over 40. It only seems to happen when its hot outside and I've driven up to operating temp. If I hold it after it shifts it will begin to surge until I get off the throttle. But if I go over 50% throttle it won't happen. It also vibrates nasty if i'm at a stop light too long.

List of new parts
-fuel tank
-fuel filter
-fuel pump
-spark plugs
-spark plug wires
-iac
-iat
-tps
-o2 sensor
-vss

The odometer reads 174797 but the guy before me didnt have a working vss. So theres no telling the real mileage. Also was a leak of transmission fluid due to lack of a vss. I'm considering buying a broken v6 transmission and rebuilding it while I keep driving ( this is my daily) yes the transmission fluid is good and the level is good.


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mcrandrz

Bump. Any one have any ideas what could be causing this ? Please!


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mcrandrz

TTTT bump?


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mcrandrz

Bump. I guess no one has any ideas? Or no v6 love?


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W.E.G.

Please clarify what you mean.

How can the RPM's go low if the transmission has downshifted?

From a purely mechanical logic, a downshift at 40 mph would make the RPM's go up significantly under normal circumstances.

Explain what you mean by "surge." This word seems to have a wide variety of interpretations as used on social media.


....or we can skip the chatter and just say you should take the thing to a transmission shop.

If the problem is actually the transmission - and it most likely is - unless you are equipped to remove, diagnose, and rebuild a transmission at your own facilities, the tranny shop is where its going in the end anyway.

The good news is, thirdgen Camaro transmissions are common as dirt, and while not dirt-cheap, will still not cost you your left nut and your first-born.

You can add "transmission" to your list of stuff you replaced on your hot rod.
It happens to the best of us.

W.E.G.

...or if you just want to know why cars sometimes take a long time to engage drive after they've been sitting, its likely a "drainback" problem with the torque converter.

If my understanding of how these things work is correct (yeah... that's a laugh), there is a valve that is supposed to keep a certain amount of fluid in the torque converter at all times. If that valve fails, the fluid drains back into the pan, and you get to wait for the system to pump the TC full of fluid when you put the transmission into drive.

This is why we are always told to check transmission fluid WHILE THE ENGINE IS RUNNING. Otherwise, if you check it while the engine is off, you can get varied and incorrect readings on the dipstick.

Raise your hand if you remember when they made cars that had dipsticks on the transmission.

fasteddi

iTrader: (2)

What he said above.

Check the tranny fluid after the trans is warmed up and you put it though all the gears. Keep it running and place it in park and check it. Make sure that is where its suppose to be.

Also check the TV cable adjustment. If you dont know how to make sure its correct just google "tv cable adjustment thirdgen" and you'll find many threads on it.

You would be surprised how closely related your(our) tranny is to a V8 one.

If you think its got some issues after that, then you can go from there. But you have to make sure these simple things are right first. Id go ahead and smell that tranny fluid also, if it smells horrid! Its burnt also check on the color. The color doesnt really mean its bad just means that its been in there a long time.

W.E.G.

While I might not actually tear transmissions apart (let alone put them back together in working condition), I'm not too bad with the googles.

Voila!: https://www.thirdgen.org/detent

fasteddi

iTrader: (2)

Well ive found that there search engine is better then TGO. Always nets good answers for me just have go to dump thirdgen in and your good.

mcrandrz

Alright. Transmission fluid is good through the gears. What I mean by the shifting thing is that it up shifts I guess. It drops about 600 rpms ( while cruising over 40 ) when it does this even if I push on gas rpms won't move. If I ignore it and keep cruising the rpms will go up and down until I get off the gas completely. I do have the tools and lift to replace / rebuild the tranny. I'm currently going to school to be a mechanic just havn't got to tranny class yet.

The tv cable is adjusted correctly.


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mcrandrz

I was thinking it was my torque converter. My teacher seems to think its a pressure issue. but I dont know how to "test" transmission pressure


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mcrandrz

My car was running 90 degrees. overcooling bad. Replaced the system. Now i'm running 180-190 and the problem is happening much more now.


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fasteddi

iTrader: (2)

There is a pressure tap somewhere although I cant remember where, but it can show you what the line pressure is. FYI our 700r4's have high line pressure.

W.E.G.

Throttle Valve line pressure fitting should be on the left side of the transmission.

Mid-way between front and back, and also midway between top and bottom.

But, the better question for the OP is this:
Even assuming you could hook into the pressure-test fitting, and even assuming that you had access to the correct specs for that port, and even assuming that you were able to diagnose the failure on the basis of the readings of the pressure-test gauge, are you in a position where you can actually pull that transmission from the vehicle, and actually make a correct repair?

Do you have the tools, and the skills to remove, and completely rebuild a transmission?

If you do, that's great. You have my admiration.

In my experience, learning transmissions is not something you do from just reading a shop manual, and giving it a go. If you have an experienced transmission guy who can show you the way, you may make it. Otherwise, transmission surgery is not for novices.

mcrandrz

Yeah my teacher is an ase certified master tech and he would personally help me. he has had 5 third gens and mine reminds him of the good days lol. I wouldn't jump in alone. I've done engine rebuilds but transmissions are not the easiest thing in the world.

I will look up in alldata where that valve is and ill post back up here if / when I find what it is.

I basically posted just for a place to start besides the basics. Thank you guy's.


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