48re not shifting

The trans will go in reverse, neutral and drive but I feel like I only have 2 gears. Since this is a cummins is in the ford, the indicator is different from the actual gears and I am new to the truck. I feel like it stays in 3rd like its in limp mode. I can gear down once to take off, and manually shift up once.

Tranny is - 2003 2wd 48re Built by Darren Morrison with DPC Converter, Billet Input and Intermediate and Suncoast VB.

I am getting these codes and was uncertain if any of these came with the swap into the F-250? I never have done a swap and didn't know if any of these were because of the swap and I can just move to the next. We have went through and checked all the fuses and found some wires that were loose connections. We fixed any loose connections we found and replaced some fuses.

These all were read with my Smarty.
P2769
P0973
P0480
P0500
P0628

Any info or guidance on where to start would be greatly appreciated!

I got in the truck yesterday morning and it shifted fine and ran through all the gears like normal. drove it a couple times and it was good. Got in it to go home for the day and It wouldn't shift again. This morning it is still not shifting. Can anyone give me some info on where I should start?

Sounds like gov transducer or sensor. Maybe somebody else will chime in, your description is kinda vague other than it's not shifting

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It's fairly common for the wiring harness to fail in these 48re's from what I gather.

Depending on the age of your trans build, a new harness might be in order. They can be purchased from Transtar. Easy to swap out once the valvebody is removed.

I would also check resistance from old to new harness. You might find the culprit that way. Process of elimination.

I really don't know what to say besides it isn't shifting. The selector on the ford doesn't match the 48re gears so I am uncertain about what gear it is stuck in. I feel like it is in 3rd gear acting like it is in limp mode, but I am not positive. I am putting it on the lift after work and we are going to take the valve body out. I have had a couple guys say it sounds like trash also. I like the idea of the wiring harness and testing the resistance. Thank you guys.

I owned this truck. Traded it in August to a guy named tommy. I dropped the pan on the trans changed fluid and filter. Adjusted front band at that time as well. Didn't pull gov press solenoid and transducer at the time. Trans filter had 100 miles on it when tommy received the truck. Not sure how much he drove it but he said he was daily driving it. Trans shifted like a dream when I had it. Clicked off gears hard and quick. Took this pic to show him verification of at least the valve body.




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Oh and about the shifter lever thing "N" on your cluster is actually "D" for the 48re. "D" is 3rd and 4th. So all the way down with lever is 1st. Click up once is 2nd and up one more to where it shows "N" is 3rd and 4th. Hope you get it figured out bud. Any questions about it just shoot me a message.


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I talked with Darren Morrison who built the transmission he told me to replace the solenoid and wiring in the tranny. I just did all that and it still wasn’t shifting. Went down the road and when I got back in the truck it was shifting perfectly fine. It has to be wiring somewhere shifting out or bad connection.


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sideways76 said:

I talked with Darren Morrison who built the transmission he told me to replace the solenoid and wiring in the tranny. I just did all that and it still wasn’t shifting. Went down the road and when I got back in the truck it was shifting perfectly fine. It has to be wiring somewhere shifting out or bad connection.


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Click to expand...

I would have ohm'd out the old and new harness on the bench to compare readings. This would have told you if the old harness had a problem.

So all is shifting good now?

One minute it is and the next it isn’t. I seen a new code P1652 short to ground. Along with all the low voltage. Someone asked if I checked my alternator. They said that stopped a vehicle they had from shifting.


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Do an ac voltage test on the alternator. Im not saying thats not it but thats normally a late 2nd gen early 3rd gen problem with trucks that have apps

AC sign test, tuck running all accessories off...anything over .03 Vac indicates bad diodes, and that will slowly start to eat other electronics. it is also know for causing lockup hunt issues, not necessarily a no shift issue.

what device is controlling the trans ?