4T-60 Transmission Worries!!!

[CutlassSL91]

I am worried about how much longer my transmission is going to last in my '91 with 175,000mi. Now hopefully this is just more of an annoyance than a potential death to the tranny, but here's whats going on:

 

-Around 38-40 mph, the car startes jerking back and forth (not the engine, thats been checked)

 

-When letting off the gas and stepping back on it, there is a nice CLUNK

 

-When stepping on the gas after coasting around a corner, there is a big rev, and then it clunks back into gear

 

-There is just an overall clunkiness for lack of a better word to it,

 

The Trans fluid and filter have been changed, lucas didn't make a difference. I am thinking its the torque coverter, but i am not pulling the TCC plug because i want overdrive. Is this thing going to be OK?

[Regal_GS_1989]

When stepping on the gas after coasting around a corner, there is a big rev, and then it clunks back into gear

My regal does this exact same thing. I have never found the cause for it, but i have found somewhat of a solution for it, if you downshift manually into 2nd, this will not occur. My shifts are also a little on the slow and soft side, so i want to put on an adjustable vacuum modulator to correct that. I have put over 20 000 km on my car since i bought it, and the trans has not gotten any worse. BTW Mine has about 390 000 Km on it and is all original.

[CutlassSL91]

i hope its just leveled off in terms of roughness, If this tranny is planning on going i am geting rid of this thing asap

[digitaloutsider]

If you "slip" out of gear going around corners, your transmission fluid is low.

[CutlassSL91]

the fluid level is to the highest point right now. i even treid running overfilled a while back, and it was still really jumpy. sometimes, if i am at a complete stop and push the gas lightly, the rpms will go way up, but the car will barely move, like it has syrup in the drivetrain

[Crazy K]

well... my 92 lumina tranny has done the free rev thing twice now at 215,000 miles. it is the original tranny, but no history is availible before I bought it at 166k.

 

the first time it free revved I added fluid, it was low.

both times it free revved after a long stretch of driving at speed, the first time coming to a full stop just long enough to pause and go.

 

it's possible that the tranny 'stalling' it is due to low line pressure, which could be corrected by replacing the pump. in fact my tranny kit came with a peg that the housing for the tranny pump rides on, so it is a known wear/trouble part, I assume. the pump assembly/body moves to adjust line pressure, and the peg is the pivot, if it was worn the pump would be maladjusted.

 

I would check the vaccuum line that feeds to modulator for carbon clogging, especially where it hits the manifold, and replace the vaccuum hose links at both ends.

otherwise try replacing the modulator.

 

 

[ns87]

I am worried about how much longer my transmission is going to last in my '91 with 175,000mi. Now hopefully this is just more of an annoyance than a potential death to the tranny, but here's whats going on:

 

-Around 38-40 mph, the car startes jerking back and forth (not the engine, thats been checked)

 

-When letting off the gas and stepping back on it, there is a nice CLUNK

 

-When stepping on the gas after coasting around a corner, there is a big rev, and then it clunks back into gear

 

-There is just an overall clunkiness for lack of a better word to it,

 

 

Mine does all those. I've flushed it at least twice, changed the filter once. Fluid level is fine, and its been doing it for almost 12k miles, not any worse. Like Regal_GS_1989 says, shift it into second manually and it wont do that. I do that twice on my way to work every day

[1990lumina]

-When letting off the gas and stepping back on it, there is a nice CLUNK

 

-When stepping on the gas after coasting around a corner, there is a big rev, and then it clunks back into gear

 

Mine does these two things....although it has gotten better it seems like (or I just don't do certain things that I know will make it slip out of gear....At low RPM in overdrive I have a bit of a driveline shutter if I accelerate without popping out of OD....I think it's the TC, but it's not that big of a deal yet.

 

Just make sure the fluids up, and there's not much else you can do....my car has been doing this since I got it (20k ago).....so I plan to just drive it and get the most I can out of it before she hits the junkyard.

[CutlassSL91]

well thanks, at least i know there's nothing majorly wrong with it now! Its just rather annoying. But with 170,000 miles whats to expect?

[Dark Ride]

-When letting off the gas and stepping back on it, there is a nice CLUNK

 

-When stepping on the gas after coasting around a corner, there is a big rev, and then it clunks back into gear

 

Same here with my GP (216K Miles) It only seems to do it when its cold, I've added fluid to it, even though my dipstick reads full, and that seemed to help for a while, but now its doing it alot. I don't want to add any more fluid to it, cuz the dipstick does say do not overfill. I've also added Trans Tune and that seemed to help as well.

 

What can having too much fluid do to the transmission?

 

Mitch

[CutlassSL91]

It will overheat and get airbubbles in the fluid. Its not a good thing

[Dark Ride]

It will overheat and get airbubbles in the fluid. Its not a good thing

My car has a tendency of leaving tranny fluid whenever it goes, so the extra fluid won't be extra for long.

 

Mitch

[CutlassSL91]

oh yeah that doesn't sound good!

[slick]

Most autocrosser's(that have auto trannys) will run there transmission a half quart overfilled for a reason- when your taking turns quick enough, the trans fluid will slosh around. Depending how much it slosh's, the pump may not be able to pick up fluid, causing it to fall out of gear to save itself from grenading. So, just add another half quart over the full line, and be happy.

 

Where, exactly does the clunk come from? In all reality, it could be a number of things thats NOT your transmission or your engine.

 

The jerking, does it feel mechanical, electrical, fuel, etc?

[ns87]

Two Woots for Reno 911..or is that Super Troopers?

[CutlassSL91]

Where, exactly does the clunk come from? In all reality, it could be a number of things thats NOT your transmission or your engine.

 

It comes from the trannny, I am almost 100% sure. I have also noticed some slight shuddering every now and then

 

[bluegp]

-Around 38-40 mph, the car startes jerking back and forth (not the engine, thats been checked)

 

-When stepping on the gas after coasting around a corner, there is a big rev, and then it clunks back into gear

 

The Trans fluid and filter have been changed, lucas didn't make a difference. I am thinking its the torque coverter, but i am not pulling the TCC plug because i want overdrive. Is this thing going to be OK?

Just speculating - the jerking around 40 MPH sounds like something that could happen when the TCC engages. If you unplug it, does the jerking still occur?

 

The thing about slipping out of gear around a corner - my GP's tranny did that right before I got it rebuilt. The mechanic at the shop said something about a shaft in the tranny that was sliding out of place (when turning a corner) because something broke/wore out. I wish I could remember the specifics of what he said. He also said that when it happens, if you jerk the car back the other way, it will sometimes go back in gear.

 

I would recommend finding a good tranny shop and have them take it for a test drive.

 

Of course, if you're not too far away, I have the tranny for you....(click for sale in my sig)

[Regal_GS_1989]

-When stepping on the gas after coasting around a corner, there is a big rev, and then it clunks back into gear

 

 

Im not too certain that it has anything to do with going around a corner. Mine will do it if i get on the gas after its coasted down to about 38 KM, and once it drops below 30 KM, it downshifts and i can get on it without this happening. It doesnt matter whether or not im going around a corner, or in a straight line, it always acts the same.