It is a built 47re, all new everything, billet single disk tc, valve body is stock but has been gone through.

Ok guys so here is the problem. This transmission has about 1400 miles on it, it has been doing great problem free for all of those miles, fluid is not burnt but turning a dark red but wasnt a burnt smell. A couple days ago i got in it and took off down the road to town, it shifted into o/d and everything was fine, i got to town and drove to another town up the road, got there and pulled into the post office to ship something, came back out, got in my truck and it wouldnt shift into o/d. Flipped my manual tc switch and the tc locked but still no o/d.

Well i ignored the problem figured it may be where i took the relay out for the manual tc switch.I put the relay back in still no o/d. Hmmm bad governor pressure solenoid maybe, so i broke down and spent $250 on a new governor pressure solenoid, sensor, o/d lock up harness, filter and new fluid. Went to pick up the parts a day later and it stopped locking the tc, the manual tc switch wouldnt lock it either.

Went home put the new parts in the transmission filled it full of brand new fluid and took it for a drive still no tc lock up or o/d. Pulled the dash apart and checked the o/d switch, it was working fine. Got a tps delete (pot) from a buddy, put it in, no matter where i put the pot it would not go into o/d or lock the tc. Checked the voltage on my tps and everything checked out perfect. Double checked my fluid levels and they were where they should be. Did a pcm reset today for the heck of it, and the tc started locking in third but would unlock about 2200 rpm (it locks at 1800) and STILL NO O/D. It only did it twice because thats all i really gave it a chance to do but i parked the truck for now till i can find out more. Checked all my wires in the pcm, everything is plugged up good like it should be.

I really need help! This is my daily driver and work on the weekends and cant get it to a transmission shop until probably wednesday. I was almost positive a new governor pressure solenoid, sensor, and lock up harness would have fixed it. I really need help and im whilling to try or test anything to help get this problem fixed, im fairly confident its not the o/d unit because the fluid wasnt burnt, no crazy amount of shavings on the magnet, and the o/d unit doesnt have anything to do with tc lock up as far as i know. Im afraid its a bad pcm but i have no way of getting it to a obd2 scanner until wednesday. Someone please help im so lost on what this problem could be?

 

1400 miles sounds like something in a hyd circuit

erratic or no OD shift is considered limp mode so its pretty much a important piece to talk to the pcm and see what going on and if dtc's are set

the smallest ammount of anthing that gets into a valvebody can make a mess of things
had a allison on a meduim duty, had 8 ft cooler lines there was a very small piece of shipping peanut, about the size of a small fingernail clipping get sucked into valve body
trashed the entire trans wich is pretty tough to do on a allison, in a nutshell it destroyed itself
limp mode is a way of preventing self destruction, gotta read those codes

good luck
scott

 

Its not throwing any codes except for battery unplugged in the last 50 cycles, and a break in the tc lock up solenoid wire(most likely my manual tc lock switch)....

So i decided to do a little testing. Its late but ive got to get this figured out, using my volt meter i ran a wire into the cab and spliced it into the brown wire(b21) on my pcm, witch my manual told me was the 3/4 solenoid control. Well ive got some weird things going on.

With the o/d off switch on(light on) the tc will lock in third, with the o/d off switch off(light off) the tc tries to lock in third but is very very weak or does not lock at all. Also as the pictures show (sorry they are blurry) with the o/d off switch on(light on) my volt meter reads 0.26 and with the o/d off switch off(light off) my volt meter reads 13.92 and 14.00 at some times. Now at no time did the voltage change on my volt meter (with switch on or off) around 45-50 where o/d should lock.

I read in a thread on diesel truck resource that my volt meter should read 12v at 45-50 where o/d should lock and if it doesnt then its an electrical problem. Does this help you guys narrow it down any? I believe my findings are kinda weird in my opinion and tells me that something electrical is defiantly wrong or is what im seeing correct?

Switch off (0.26)



Switch on (13.92)