Recall 15304 Transfer Case Reprogram and Set Up

[Tattooo]

My clunking reduced to hardly never

[Newell33]

 

It does nothing for driveability as it does not do anything to the TCM (Transmission control module), the TCCM (Transfer Case Control Module) is what is reprogrammed, the recall is so that the transfer case doesn't get hosed during cold weather when left in auto or 4wd as some were doing last winter.

 

Absolutely incorrect on the driveability comment. My truck drives completely different after the recall. I actually enjoy it now. From the other thread, it seems like about 65% of folks that had problems before are experiencing a completely different truck, and about 35% state no change. I have no explanation as to why, but all I can say is that it was night and day for me.

[Badass69]

Yeah I don't get this thing... it's just the tccm being reprogrammed which has nothing to do with the transmission or the engine. Maybe it's just the fact they reset the adaptives that everyone somehow feels a difference. Reprogramming the tccm and reprogramming let's say the intellilink screens software will have about the same effect on drivability lol.

 

Mine drives different but they cleared the adaptives and changed a harness in the transmission. All it changed was my tranny was clunky and stupid when it's cold... and now it's not. Otherwise the truck drives just like it did before. That's a problem specific to the 8L90E though and nothing else....

 

Sent from a potato

[Newell33]

Yeah I don't get this thing... it's just the tccm being reprogrammed which has nothing to do with the transmission or the engine. Maybe it's just the fact they reset the adaptives that everyone somehow feels a difference. Reprogramming the tccm and reprogramming let's say the intellilink screens software will have about the same effect on drivability lol.

 

Mine drives different but they cleared the adaptives and changed a harness in the transmission. All it changed was my tranny was clunky and stupid when it's cold... and now it's not. Otherwise the truck drives just like it did before. That's a problem specific to the 8L90E though and nothing else....

 

Sent from a potato

 

I believe I read that the harness replacement addresses a resistor issue (don't quote me on the resistor part) that was causing the poor performance in cold weather. The new harness had an updated resistor that was unaffected by the temperature, thus fixing that part of the problem.

[Badass69]

 

I believe I read that the harness replacement addresses a resistor issue (don't quote me on the resistor part) that was causing the poor performance in cold weather. The new harness had an updated resistor that was unaffected by the temperature, thus fixing that part of the problem.

Thermistor.... it's a type of rtd. It's what the tcm uses to measure Trans temp. Supposedly the supplier for the harnesses started using a different one than the original spec so the resistance value at low temp was off and made the transmission stumble and clunk. The new harness improved mine when it's cold for sure.

 

Sent from a potato

[TJay74]

I had mine done yesterday, still drives the same. I could maybe see GM resetting the trans adapts during the TCCM update, but as of this morning everything was driving like it was before.

[Tattooo]

Its weird how it works for some but not others

[CounterMeasure]

I had mine done yesterday, still drives the same. I could maybe see GM resetting the trans adapts during the TCCM update, but as of this morning everything was driving like it was before.

 

I think you are on to something here. I had the update done, and it shifted much better for the first 100 miles or so. Then became more rough and bangy, and has since settled down to about where it was before, if not a bit better. My paperwork clearly starts they reset the shift data.

 

As I don't think the transmission is hunting as much as it did before, I'll take it!

[ChipEric]

My experience with an inTune showed that the transmission relearns back to crappy behavior after a tune, after some time (hundreds of miles).

[Jordan18]

Mine felt more responsive after a service and this transfer case update was done. Still makes me smile to have gotten a 6.2L.

[Ventilator]

Just had this done Thursday, and I wish now I had left well enough alone.

 

I haven't heard the dreaded clunk in quite some time now, and the truck was getting great gas mileage. There was a touch of shift flare between the early gears, but just barely.

 

Thursday's driving was not really much different. Then last night I was slowing down to make a turn and the dreaded clunk reared its ugly head. Immediately after, I was driving slow in a parking lot and I was getting some kind of ticking noise at very low speed. Never once have I heard that noise before. So now I think I killed my good gas mileage again until some learning gets done, and now I have the dreaded clunk back and a new ticking noise.

 

I live 2-1/2 miles off the beaten path (pavement), so it might be next week some time before I can try and diagnose where the ticking is coming from.

 

I've already been through two cold Michigan winters with the truck, so I wasn't worried about the TC sticking in 4x4, as I've never had a problem with that. I got this done to see if I could get rid of the flare, as small as it was. There might be some slight improvement in that, but to early to tell for sure.

[Ventilator]

 

I think you are on to something here. I had the update done, and it shifted much better for the first 100 miles or so. Then became more rough and bangy, and has since settled down to about where it was before, if not a bit better. My paperwork clearly starts they reset the shift data.

 

As I don't think the transmission is hunting as much as it did before, I'll take it!

This sounds real close to my experience. I had it done Thursday, and drove it for about 90 miles later that day. Yesterday I put an additional 28 miles on it, parked for 8.5 hours. After work I drove to a gas station about 1.5 miles away, filled up, then drove a half mile down the road to stop at a store. When slowing down, the dreaded clunk, then something totally new, a low speed clicking/ticking noise. Sounds like either from the drive line or suspension. Didn't have time to try and diagnose it right then, but will the next time I hit the pavement. The 30 mile drive back home was clunkless,

 

We have had warm weather all week, then it cooled down quite a bit yesterday, and all the components were not up to NOT at the time of the clunk. I usually don't do much city driving when the truck is cold, as that is the last place I want to be after work. I put that in the rear view mirror as soon as possible.

 

I'll let you know how it goes when I head to the concrete jungle again next week.

[glcbn]

I had my truck inspected today, and they did the transfer case update. Right out of the dealership, I noticed it shifted different. A good different. My truck has 31,000 on it, and I am very "used" to the way it drives. It is definitely different.

 

About mid week, when I've put around 250 more miles on 'er, I'll post again.

[rshad]

I have a 2015 SLT Sierra 1500 5.3ltr. that I picked up last week. How can I find out if this updates has been done to my truck or not?

[tainoxl]

Just had mine in for oil change yesterday and they did the update and rear brake line bracket recall. I will say the difference is there. Definitely shifts smoother. Feels more responsive. Maybe just the TCM relearn because they reset power to all electronics?