Slipping Transmission

Raf20 · January 9, 2005

Hi folks, new to the board. I have a 2004 Chev Silverado 2500HD 4x4 with 6.0L and 4 speed trans. It has 9000 miles on it.

The transmission occasionally slips when accelerating from a dead stop. I have read posts from owners of older model trucks but would like to know if this has happened to owners of 2004 or 2005 trucks?

Thanks!

Raf20

GM-Tech · January 9, 2005

Are you sure it's not the fan clutch? We get that a lot, though usually only in the dead of summer when it's hot enough for that to come on regularly. Still, it could be a bad fan clutch and not temperature dependent.

What happens is that when the fan clutch is on, you get a LOUD roaring noise and pulling all that air causes a noticeable reduction in engine power. Many people misinterpret that as a slipping trans. Easy enough to tell. When it does it, slip it into neutral real fast and rev the engine. Same roaring noise? It's the fan clutch.

Haulin' 8.1 · January 9, 2005

Did you check the fluid level? 90% this comes into our shop that's the problem.

Vernon

Beer Belly · January 9, 2005

I have experienced the same thing, every once in a while from a dead stop, it happens just at the lower RPMs, just as you're touching the throttle, not a BANG into gear and go, but just feels like it's slipping....your giving it gas and it seems to sit there for a second. 2004 2500HD 6.0L, 8,000 miles and already replaced a Front Diff....could the Tranny be next?

Raf20 · January 10, 2005

Beer Belly, my experience is exactly the way you described.

GM Tech, there is no "roaring noise", or any different noise at all.

Light throttle from a dead stop, engine revs up but doesn't get into gear for about a second.

Haulin, I've checked the trans. fluid level and it's fine.

Raf20

Shaners · January 10, 2005

Mine used to do it... Some times it would rev past 2 grand before the truck would move. When it finally started to go it would bang into gear like it was in neutral and then you pulled it iinto "D". Luckily, my dealer was able to duplicate it, and he solved the problem with an update to the computer.

Beer Belly · January 10, 2005

This situation comes and goes...unpredictable, having it happen with a tech driving would be a miracle. I'll just wait for the Tranny to blow up....the way this truck has been, it should happen at the most incovinient time. Very disappointed in the reliability of this truck...but I'm in it for the long haul regardless.

COSilver · January 10, 2005

My 04 6.0 HD has done exactly the same thing Beer Belly - there was no banging back into gear, it just would kind of slowly start "sliding" into gear and then run fine. I took it in for a loud ticking noise coming from under the engine, and the dealer replaced the Flex plate/flywheel because it was cracked. What they said about the tranny slippage was that because of the flexplate issue it was sending inaccurate signals to the computer, causing this. It hasn't happened since then, but in about 8000 miles it only did it 4 or 5 times, so we'll see. The cracked flex plate is a recall item from GM, so they are aware of it.

GM-Tech · January 10, 2005

The cracked flex plate is a recall item from GM, so they are aware of it.

I work for chevy and I'm not aware of it! I am familiar with all the recalls we have ongoing and that isn't one that I've ever heard of. Maybe a TSB, but that's not the same thing.

lazer · January 10, 2005

I had an 02 hd that didn't shift right from the day I bought it new. The dealer couldn't find anything wrong. A year and a half later and 8000 miles it began to slip badly and make a snapping noise when it finally went into gear. I barely made it to the dealer. He replaced the tranny with a refurbished one from GM and the truck was trouble free until I traded it in a few weeks ago on an 05. This new one seems to shift the way it is suppose to and even better than the new tranny they put in my previous truck.

COSilver · January 10, 2005

The cracked flex plate is a recall item from GM, so they are aware of it.

I work for chevy and I'm not aware of it! I am familiar with all the recalls we have ongoing and that isn't one that I've ever heard of. Maybe a TSB, but that's not the same thing.

<{POST_SNAPBACK}>

Maybe it was a TSB, the tech at the dealership showed me a document from GM describing the issue and the known cracking of the flex plate. Replacing this fixed the very loud ticking noise, and hopefully this trans slipping, but we'll see.