'04 2500HD Trans slipping?

Beer Belly · December 12, 2004

It doesn't happen often, but once in a while, on take off (light acceleration) it feels as if the rear tires are on ice. Its hard to describe, but it feels like the motor revs slightly before the trans engages to move the truck, I'm not on ice, water or anything on the road, but it almost feels like Clutch slippage. Anyone else experience this?.

mikebsilvey · December 14, 2004

It doesn't happen often, but once in a while, on take off (light acceleration) it feels as if the rear tires are on ice. Its hard to describe, but it feels like the motor revs slightly before the trans engages to move the truck, I'm not on ice, water or anything on the road, but it almost feels like Clutch slippage. Anyone else experience this?.

<{POST_SNAPBACK}>

Yup i have a 2004 with the allison trans in it and i can count to three before i even move. By the way this is my second trans in this brand new truck. Feels just like i am spinning but i am not even moving.

Beer Belly · December 14, 2004

Mike, I wish I had the Allison...at least I'd have an answer to my problem...but I have the 6.0L. , the Allison isn't available

COSilver · December 29, 2004

I have the exact same problem with my 04 2500HDH/6.0L. It has only happened 3 or 4 times with almost 8K miles on it. My truck (Emily) is in the dealer today getting a cracked flex plate replaced (she makes very loud ticking noise at idle all the time - and it's not csk or piston slap) and I told them about the tranny slip issue also. They asked me if the RPMs move when this happens, but I haven't noticed - it happens so unexpectedly and for a short time only that I haven't thought about looking at the RPMs when it does happen.

You're not alone, Beer Belly.

Beer Belly · December 29, 2004

My baby is also in the dealer today, put it in 4WD for the second time since I've owned it and it's making a God awful Grinding/Clunking noise, like a combination of Brakes being Metal to Metal and really dry bearing.

COSilver · December 29, 2004

Ouch, sounds nasty. Thank goodness I don't have that, I've put mine in 4wd several times, and all sounds/feels well with it, feels very solid.

Mighty HD · December 29, 2004

Mine has done it 2-3 times as well. I haven't taken it to the stealership yet though.

COSilver · December 30, 2004

According to Mr. Goodwrench at the dealer...

The cracked flex plate/Fly wheel that was replaced was "Causing signal to crank to vary slightly", thus causing the slippage we are describing here.

They replaced the flex plate, and I have to admit that it seems to run and shift smoother (but maybe it's just me), and the loud ticking noise it was making is definitely gone.

So, hopefully this issue of slipping will also be resolved. We'll see.

The cracked flex plate/fly wheel is actually a recall item with GM, so this may be a somewhat common problem. If you guys have any kind of a ticking noise coming from under the truck, you also may have a defective flex plate.