Chevy and GMC Duramax Diesel Forum banner
  • Hey Everyone! Enter your ride HERE to be a part of this months Ride of the Month Challenge!

1 - 5 of 5 Posts

·
Registered
Joined
·
114 Posts
Discussion Starter · #1 ·
I got my truck about a month ago and love it!! I have done several full throttle launches (racing people) and the torque converter has never shown it slipping when locked up (on my edge gauge). Today I was towing a trailer back from our cabin, going downhill in T/H mode about 35 MPH. I Hit the brakes to slow down for a corner and my truck downshifted from 3rd to 2nd and showed a slip of 27%, I continued to show it slipping until I kicked it out of T/H mode and gave it some throttle, it unlocked and shifted up a gear. The rest of the way home I stepped on it a few times and it never showed a slip again??? It has only done this one other time, again when it was downshifting in T/H mode. So what the heck, Is my edge gauge just getting a bad reading or was it really slipping?? It never heats up and has never thrown a code.. Do I need to worry about it at all?? Any help on this issue would be great. Thanks!!
 

·
Registered
Joined
·
3,642 Posts
I got my truck about a month ago and love it!! I have done several full throttle launches (racing people) and the torque converter has never shown it slipping when locked up (on my edge gauge). Today I was towing a trailer back from our cabin, going downhill in T/H mode about 35 MPH. I Hit the brakes to slow down for a corner and my truck downshifted from 3rd to 2nd and showed a slip of 27%, I continued to show it slipping until I kicked it out of T/H mode and gave it some throttle, it unlocked and shifted up a gear. The rest of the way home I stepped on it a few times and it never showed a slip again??? It has only done this one other time, again when it was downshifting in T/H mode. So what the heck, Is my edge gauge just getting a bad reading or was it really slipping?? It never heats up and has never thrown a code.. Do I need to worry about it at all?? Any help on this issue would be great. Thanks!!
If it was a steep road and there was sand or gravel or something, the ABS was probably kicked in slightly, or was right on the threshold. Anytime the ABS kicks in, or the wheel speed drops rapidly (like if the wheels are in danger of locking up), the TCM will immediately unlock the TC as a safety feature to allow the ABS to work properly...if the wheels locked up or ABS engaged with the converter still locked, it would also most likely stall the engine.

Once an ABS event or near-ABS event has occurred and forced a TC unlock, the TCM will wait a couple seconds for wheel speeds and turbine/input shaft speeds in the trans to stabilize before allowing the converter to re-lock. Thats why you had to play with the throttle a bit and there was a delay in the re-lock.

So basically....skipping over all the techno mumbo-jumbo, what you saw was perfectly normal operation and nothing broken/nothing to worry about...

ben
 

·
Registered
Joined
·
114 Posts
Discussion Starter · #3 ·
Thanks for the response. Just so we are clear this was on a paved road and i'm sure the tires were not slipping at all. Also everything felt normal i just have never seen any other number besides 0% on the trans slip gauge so I started to worry. Sounds like I don't have anything to worry about. If anyone else has had experience with this I would love to hear from you. Thanks again Ben
 

·
Registered
Joined
·
3,642 Posts
Thanks for the response. Just so we are clear this was on a paved road and i'm sure the tires were not slipping at all. Also everything felt normal i just have never seen any other number besides 0% on the trans slip gauge so I started to worry. Sounds like I don't have anything to worry about. If anyone else has had experience with this I would love to hear from you. Thanks again Ben
Its pretty sensitive as to what sort of wheel decel speed/difference it will take to force a TC unlock...even if a downshift happens too quickly it can freak out and unlock.
 
1 - 5 of 5 Posts
Top