Transmission shudder

[mudpie]

I did a search and came up with threads mostly related to the 4L60, and one thread related to the 4L80 that had one post and no response.

I've got a '96 C2500HD. It's got a ton of miles, and I have no idea if the trans is original. The fluid color is good, and it's clean. A couple weeks ago it developed a very slight shudder when I'm getting on the highway and it shifts from 3rd to overdrive. Nothing is slipping, and the other shifts seem fine.

What might be starting to go bad? In the 4L60 threads it seems the torque converter, but I read several where replacing the TC only fixed the problem for a short while. Is this an issue of trans wear and TC wear that both contribute to an issue?

Any thoughts appreciated.

 

[Oldblue98]

I did a search and came up with threads mostly related to the 4L60, and one thread related to the 4L80 that had one post and no response.

I've got a '96 C2500HD. It's got a ton of miles, and I have no idea if the trans is original. The fluid color is good, and it's clean. A couple weeks ago it developed a very slight shudder when I'm getting on the highway and it shifts from 3rd to overdrive. Nothing is slipping, and the other shifts seem fine.

What might be starting to go bad? In the 4L60 threads it seems the torque converter, but I read several where replacing the TC only fixed the problem for a short while. Is this an issue of trans wear and TC wear that both contribute to an issue?

Any thoughts appreciated.

At the speed it is shuddering slightly apply the brake just enough to trigger the brake light switch and see if the shudder stops/goes away. If it does it is a TC issue. Not knowing if the trans has equal tons of miles it is hard to say if you are throwing good money after bad or not.
TC are remans and it is a bit of a crap shoot with a rebuilt tc , my transmission was rebuilt and they put a reman tc in at that time and it shuddered and had to be replaced under warranty.
Buying used transmissions is a crap shoot, you may get a warranty promise on a used trans but it is no fun doing it the first time even less the second.
Depending on your budget and how much you like the truck depends on what to do at this time.

 

[Terrick down Under]

I am curious to hear everyone's opinion on this, as we have the same thing happening down here on our little ute.

 

[mountie]

I am curious to hear everyone's opinion on this, as we have the same thing happening down here on our little ute.

Google " California Performance Transmissions", ( Southern California)
The owner is the famed Art Carr. ( I know him & my transmission was built there)
He may give you advice.

They do hand built TC's there also

 

[mudpie]

...slightly apply the brake just enough to trigger the brake light switch and see if the shudder stops/goes away. If it does it is a TC issue.

So as I'm accelerating onto the highway, I apply the brake a little? I assume I'm trying to apply a load to the engine/trans? Would I get the same result then if I was hauling a load of rocks? Just curious. I know nothing about how torque converters work. I'm just trying to understand the mechanics of it.

I'll check it tomorrow and report back.

 

[Stokes1114]

No you don't want the brakes to activate at all, just the brake light switch. When the switch is applied the tc unlocks and if the shudder goes away, then you know that's the culprit.

 

[Oldblue98]

No you don't want the brakes to activate at all, just the brake light switch. When the switch is applied the tc unlocks and if the shudder goes away, then you know that's the culprit.

X2

 

[JJDAG]

I did a search and came up with threads mostly related to the 4L60, and one thread related to the 4L80 that had one post and no response.

I've got a '96 C2500HD. It's got a ton of miles, and I have no idea if the trans is original. The fluid color is good, and it's clean. A couple weeks ago it developed a very slight shudder when I'm getting on the highway and it shifts from 3rd to overdrive. Nothing is slipping, and the other shifts seem fine.

What might be starting to go bad? In the 4L60 threads it seems the torque converter, but I read several where replacing the TC only fixed the problem for a short while. Is this an issue of trans wear and TC wear that both contribute to an issue?

Any thoughts appreciated.

I had the same problem with my 98 K1500 350/ auto , I read up on this and found the tcc solinoid was the culprit mainly due to it sticking . Many recommended to try a tube of shudder fix from the parts store cost me $7 2 years ago still no shudder . To be clear I am not a fan of fix it in a bottle for anything, but the $7 bux was worth the shot. Either way it won’t hurt anything .
Good luck

 

[mistaake]

Dr Tranny Shudder Fix. Never tried it in a GM tranny but this stuff works wonders for Ford 4R70Ws which often have torque converter shudder issues.

 

[mudpie]

Usually when I'm getting on the highway to go to work, it only does it for maybe half a second, and I haven't been able to catch it. Today I was rolling down the road and must have been going just the right speed because it started to shudder and continued for 3 or 4 seconds. I put my foot on the brake slightly and it stopped immediately.

I did a search on transmission shudder and found a page that said it "is usually caused when there is a buildup of contaminants in your automatic transmission fluid." I find this a bit odd since the fluid color is good, and it's clear. How I came to own the truck is a long story, but I'm convinced the previous owner was on top of all the maintenance. I don't see a build up of contaminants being the cause.

Regardless, I suppose I'll throw a bottle of magic in it and see what happens. If it's a tcc solenoid, is this something that progressively gets worse, or does it un-stick when I pour whatever into the transmission? And if I can't find Dr. Tranny Shudder Fix, is there something else any of you would recommend?

Thanks for the input.