2019 L5P clunk

SBISHOP370

New member
May 24, 2008
22
0
1
BEAUMONT CA
When towing or when it's cold the truck has a real hard clunk when coming to a stop. Is there any fix for it or is that just the way it is? Took it into the dealership they told me it's the programming of the transmission are they right? Thanks for the help
 
Last edited:

Chavez91

People Go Outside?
May 30, 2012
139
2
18
Heh. Wouldn't you like to know
If its a stock trans, I would get your TCM calibrations updated to the latest and greatest. There was a 2-1, 1-2 tie up issue in the early cals that was supposedly fixed mid to end last year in a calibration update. It would be your best and easiest start.
 

SBISHOP370

New member
May 24, 2008
22
0
1
BEAUMONT CA
I did that in February. The dealer upload the new programs when I was telling them about my problems. The dealer said that should fix it. Well guess what it's still doing it. Took the trailer down to the lake last week and when coming to a stop it made a clunk the wife even noticed. Took off from the stop and all seams to be well. Just makes chunks when coming to a stop when towing or when it's cold.
 

TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
15,611
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Mid Michigan
Granted, there's probably not enough mileage on these newer trucks to know for sure, but could the L5Ps have the same issue with the driveshaft yokes binding at the rear of the Tcase that the older trucks did?
 

NC-smokinlmm

<<<Future tuna killer
May 29, 2011
5,201
363
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At Da Beach
Just about every l5p I've driven has wierd up shift and down shifts, I think it's to keep the emmisions down. Drives me nuts but probally bc I still own an LML that's smooth as silk. Lol.
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
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Just about every l5p I've driven has wierd up shift and down shifts, I think it's to keep the emmisions down. Drives me nuts but probally bc I still own an LML that's smooth as silk. Lol.

stock LML's are no better.

When towing or when it's cold the truck has a real hard clunk when coming to a stop. Is there any fix for it or is that just the way it is? Took it into the dealership they told me it's the programming of the transmission are they right? Thanks for the help

Anything else done besides the derringer and throttle booster? have you tried removing the booster to see if it stops? how many miles on the truck?
 

SBISHOP370

New member
May 24, 2008
22
0
1
BEAUMONT CA
thing else done besides the derringer and throttle booster? have you tried removing the booster to see if it stops? how many miles on the truck?
S&B cold air intake and I've got about 23500 miles on the truck. When I took the truck to the dealership I removed the Derringer, the throttle booster and the cold air intake. It still did the same coming to a stop it would clunk. This just seems weird.
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,681
5,833
113
Phoenix Az
leave the throttle adjustment out for a hundred or so miles, see if the clunk starts to go away. stop and go with a few key cycles (1 min + wait time between off and back on) in between there within that 100 miles is best
 

SBISHOP370

New member
May 24, 2008
22
0
1
BEAUMONT CA
I talked to a guy on the phone today from Redlands truck and RV . He told me the the clunking is from the programming of the transmission. The guy told me it's pressure unloading. Now I know zero about Transmissions and how they work. Was the guy trying to sell me $400 in part/labor or was he blowing smoke up my ass. Kept calling it a solenoid kit. Told me it would maintain pressure and not clunk.
 

Chavez91

People Go Outside?
May 30, 2012
139
2
18
Heh. Wouldn't you like to know
I talked to a guy on the phone today from Redlands truck and RV . He told me the the clunking is from the programming of the transmission. The guy told me it's pressure unloading. Now I know zero about Transmissions and how they work. Was the guy trying to sell me $400 in part/labor or was he blowing smoke up my ass. Kept calling it a solenoid kit. Told me it would maintain pressure and not clunk.

Lol Dummy Solenoid. xD