Downshift Clunking in Transmission

[H2Norcal]

Anyone out there experiencing an annoying drive train clunk when the H2 is slowing (15-25mph) and then accelerating (like you are slowing for a red light and it turns green).

I have driven at least 3 during my selection process and all of them seem to have it. Some worse than others. I had the same problems with a '99 Dodge 3/4 truck and it could not be resolved.

It appears to be some type of drivetrain lash when the transmission gets confused as it is down shifting and then suddenly must accelerate.

My 2500HD Sierra 6.0 Vortec truck with the same basic transmission internals does not do this.

[H2Norcal]

Anyone out there experiencing an annoying drive train clunk when the H2 is slowing (15-25mph) and then accelerating (like you are slowing for a red light and it turns green).

I have driven at least 3 during my selection process and all of them seem to have it. Some worse than others. I had the same problems with a '99 Dodge 3/4 truck and it could not be resolved.

It appears to be some type of drivetrain lash when the transmission gets confused as it is down shifting and then suddenly must accelerate.

My 2500HD Sierra 6.0 Vortec truck with the same basic transmission internals does not do this.

[Steve R]

hmmm....low tranny fluid can sometimes cause hesitant shifting. Hate to say it, but sounds like it's a visit to the dealer. No such problem/observation with my rig.

[H2Norcal]

Thanks. I thought it may be an isolated situation but it has reared its ugly head in three test drives, all different vehicles.

Last week the dealer let me take an H2 out for a three hour test drive. I used it good (politely) but good. It had 200mi. and had the worst clunk of all of them. Happens around town a lot.

I recall reading a tech bulletin about something similar to this problem on the forum. The fix was mostly try this, try that and if the customer isn't happy, call the H2 dealer tech center.

[Texas Red]

Haven't noticed anything like that on my rig either.

Jim
Red H2 in Texas

[H2Norcal]

Thx Jim. Maybe I am too picky for an automatic transmission. I never seem to be happy with how the manufacturer choses to shift for me.

The tech bulletin worries me that there is something going on though. We'll see.

Cheers.

[MAC]

No such noise.

[JJ]

No issue here, 1800+ miles

JJ