47RE kicking out of O/D

[TCMagnum]

I said i'd have some questions about my dads truck so here goes...

2001 Ram 2500 24 valve, 47RE automatic. Transmission was rebuilt years ago before he had the truck. not sure what all was done to it specifically.

It will randomly kick out of Overdrive sometimes cruising around 55mph, sometimes cruising at 60/65mph. It will kick in and out of overdrive 2 or 3 times in a row and then go back in and hold.

When he first described the problem to me i wasn't sure if it was O/D or Lock up giving an issue.. So i did the first test in the Alternator noise thread about isolating the alternator by removing the field wires and removing the 140 amp fuse in the box, went for a drive and the problem persisted and i was able to see that when it drops out it goes from cruising at around 18-1900 rpm at 55mph to 23-2400rpm at 55mph, so at this point i was certain it was Overdrive dropping out and not TC lockup.

Now my next question is he has a P0122 'A' code for APPS sensor, could this have an affect like that? We've done that APPS reset procedure for the heck of it and it had no change on the problem. I'm not sure if the APPS has any play into transmission shift control or not.

 

Edited 10 hours ago by TCMagnum

[Mace]

WT mod should be done in full first. I don’t have much troubleshooting experience with autos as I have the 6 spd but from what I understand a lot of issues are solved when the mod is done. At least you can rule that out.

[Tractorman]

@TCMagnum, Good job determining that that it is actually downshifting to 3rd gear.

 

I don't think you have an AC noise issue, although performing the W-T ground reference mod would be a good idea, if you haven't done that already.  Usually, AC noise affects torque converter lockup stability which is the problem most people have.

 

When the transmission does an unwanted downshift, does the torque converter lock up, or does it stay unlocked?

 

What about the code - P0122 Accelerator Position Sensor (APPS)
Signal Voltage Too Low, is it still there?  If it is, I would get that cleared up first.

 

- John

 

 

 

[TCMagnum]

I don't know if he did the WT mod fully, he rerouted a ground wire that runs with the alternator wire that runs across the front of the engine and behind the alternator and ran it across the top of the front radiator support .