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 February 8Feb 8 by TCMagnum

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.

@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

 

 

 

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 .

Quick update, after replacing cable ends, cleaning grounds, no change. Replaced the APPS sensor and did the relearn procedure and i cleared the code and so far that P0122 code has not come back and he's driven it everyday, which to me seems a little odd as that code in the manual tends to point towards a wiring short. He also swapped trans relays, and it did better got up to 70 before it started dropping out of O/D. 

Would band adjustment have anything to do with this? 

Edited February 14Feb 14 by TCMagnum

Both bands should be adjusted as they probably have never been done unless the trans has been fully rebuilt.

 

I just adjusted both bands on my buddy's 48RE, and now it shifts correctly from 2nd to 3rd gear without having the shift delay it was having.

1 hour ago, 01_Cummins_4x4 said:

Both bands should be adjusted as they probably have never been done unless the trans has been fully rebuilt.

 

I just adjusted both bands on my buddy's 48RE, and now it shifts correctly from 2nd to 3rd gear without having the shift delay it was having.

It was rebuilt 10+ years ago

I bet both bands are too loose now after 10 years. For a couple hours of time, and a trans filter and some ATF, it would be a simple thing to adjust them to see if it helps your issue.

On 2/15/2025 at 11:51 AM, TCMagnum said:

It was rebuilt 10+ years ago

What kind of mileage since the rebuild? 

On 2/17/2025 at 1:16 PM, Mopar1973Man said:

What kind of mileage since the rebuild? 

I would say no more than 30K...and that's a little generous. It sat for a few years without being driven.

Yeah band adjust should be done every 30k with filter and fluid change. Grab a FSM is going to have the torque specs and slack

 

So at this point i'm thinking we should do the band adjustments and a solenoid upgrade. What do y'all think about this kit. https://www.oregonperformancetransmission.com/product/OPT-A518-A618-EL.html

 also want opinions on maybe doing a shift kit too?

https://superiortransmission.com/product/superior-k500-618-l/

Looks like a good little shift kit. Pay attention to the drill locations. 

Well I think the old man's truck is fixed...

I had a gut feeling before  tearing into the trans, something less invasive should be attempted first,  after some more reading about the 47re online, and noting some "weird" issues caused by the output speed sensor, we removed the OSS and found this. ,(see picture)

Installed a new speed sensor and he took it for a test drive, got it up to operating temperature and drove 30 miles round trip with NO issues,  and most important,no  random kicking out of overdrive. Which before you couldn't go 5 miles without it happening.

Edited March 11Mar 11 by TCMagnum
Add picture

Good thinking on your part!

 

- John

2 trips to town today due to working on another vehicle with 0 shift issues.

👍🏻

Only had one output speed sensor to replace in 22 years of doing this. Rare but yeah does happen.

I had the same problem on a 2001 I had for a short time OD would drop out randomly. It had a ton of problems. (Full of water) but the OD issue wound up being the APPS. I swapped the unit from my 2000 daily into into it and it drove perfectly.

1 month later and two 500 mile round trips in it and ZERO issues.

Glad to hear it's working right after 1k miles.