Atomic

iTrader: (42)

Correct.

Bumpers

iTrader: (10)

Ok well its not in the tuning I'm hoping its the maf

Atomic

iTrader: (42)

Why do you keep thinking its the MAF?

04Silverado5.3

For the trans to be in 4th gear with the TCC locked at 25 mph the PCM thinks the truck is in 4 LOW. I remember there was either at Technical Service Bulletin or Preliminary Information from GM about this, but I am not able to find it. You need to check with a scan tool to see what the PCM see for 4 LOW switch status.

oldred95

I didn't feel like reading three pages so I will just tell you what the problem is. Your encoder motor position sensor is junk. My dads 2005 did this, I've seen a 99 even do this but on it the transfer case control module had died. Basically what is happening in your case is the encoder sensor is sending the wrong signal to the transfer case control module. Its saying that its in 4wd low when its not. When this happens the transfer case control module tells the PCM that its in 4wd and the PCM in turn changes up the shift routines thinking its in 4wd low. It shifts through the gears very quickly and by about 25 mph you will be in OD and trying to lock the converter at like 500 rpms and you end up getting spark knock and bucking because the engine is being lugged to death. Fix your service 4wd issue and your tranny issue will be fixed to. Really its nothing wrong with the tranny, just the PCM not knowing whether its in 2 high or 4wd low.

Your welcome.

Bumpers

iTrader: (10)

I have been riding for 3 days now with the maf unhooked and it hasn't had a single hiccup.. The transfercase and the pcm think that the case is in nuetral and its lit up on the dash that its in neutral... I think I have two sperate problems here

Bumpers

iTrader: (10)

Oh and did I mention it only does the fast shifting and tq locking when its warm?

Tootall

iTrader: (79)

replace your dash switch,
If it keeps happening, then it's the 4wd actuator

It's not the MAF

oldred95

The switch issue is really more of a 99-02 issue. Not saying it can't happen on the 03+ trucks but its not nearly as common. If you have a C0327 fix it first. Thats the encoder sensor.


I agree its not a MAF issue. Why does it only do it when the engine is warm? Thats anyones guess. Probably because it wants to.

Bumpers

iTrader: (10)

already changed the switch

because if its what i think it is the maf has lost its calibration and causes the truck to think its moving more than it is and shift really fast and then trys locking the converter thinking its over 50mph wich is my lockup speed. the reason it would do it when its warm is because thats when the sensor starts working. when you first crank the truck up its either in a closed loop or open loop ( cant rember wich is wich) but it isnt until the truck heat up alittle that the maf start adjusting. i could be wrong but im thinking this is my problem and only time will tell but for 3 days so far with the maf unplugged no issue and with the new maf no an issue yet and ive prolly put 100 miles on it.