kicks in to tow mode while running on highway

goinonforty · 07-29-2008, 04:46 PM

when im running down the highway my 2001 3500 crew cab 4x4 will be revving at 1900 rpm then kick down and be revving at 3000 rpm its like it kicks into tow mode if i pull over and shut off it stops can run for 12 hours at 65 mph without happening then boom just happens had it scanned and 2 codes came up p0571 and p0700 any ideas

**BigRedChevy** · 07-29-2008, 05:14 PM

P0751 Shift Solenoid A Perf/Stuck Off

Are you running any power adders? It sounds like it may be a valve body problem. I have a cousin that was having the same problem with his 02 duramax allison and 01 8.1L/allison. They had to replace the valve body on both of his.

goinonforty · 07-29-2008, 05:30 PM

bone stock just 4 inch exhaust i put 2200 miles on it this weekend and it happened twice as soon as i shut it down and restart it is fine

**ob_1jr** · 07-30-2008, 05:54 AM

when is the last time you changed your tranny spin-on filter? or the tranny fluid? It is a sticky solenoid. It is your tranny going into limp mode...it is locking out 5th gear. So, did you buy this truck used? someone could have had a programmer on it. Also, is the T/H mode light coming on when this happens or just a check engine light?

goinonforty · 07-30-2008, 02:15 PM

just bought it so i dont know when the filter was changed and no the t/m light does not come on just the service engine light i actually bought the truck last weekend and drove it home the 2200 miles i will change the trnny fluid and both filters this week and see how it is

**ob_1jr** · 07-30-2008, 02:51 PM

yeah, that is limp mode for the tranny. Hopefully someone didn't abuse that tranny with a programmer before you bought the truck. If the fluid/filter change doesn't solve the problem, you will have to pull the valve body and possibly do a rebuild or get it worked on to stop the sticky solenoid. I think that if your truck was abused, you would be getting different DTCs for the tranny, like incorrect 5th gear ratio...so, maybe they never changed the fluid and filter out..also, there should be a magnet on top of the old spin-on filter....make sure to clean and reuse it if it is there...if not, it is like a $10 part from the dealer.

goinonforty · 07-31-2008, 11:06 AM

thanks for all your help i will let you know how it goes after the oil change