Hey, this is my daughter's truck, '98 12 valve. Her fiancee was using it to pull a skid steer on a trailer and had to go through a soft spot in a driveway. He said he stopped and put it in 4wd (don't know if hi or low) and proceeded to go easy through the soft spot (or so he thought!)....... When the trailer was in the soft spot he said it almost ran out of power and almost stalled. He stopped, unloaded the skid steer and drove out. That is when he said there was no reverse. All he had was forward no matter where the shifter was even in park. Sometimes he said he could 'find' neutral, but reverse was forward and backward fighting each other. It doesn't seem to be a linkage issue since it will start in park or neutral. I am in Alabama and he is in Minnesota with the truck. I have been wracking my feeble brain trying to figure this one out. Any ideas? Fluid clean and no sparkles............

Edited October 16, 20186 yr by MnTom

Engine running backwards? Check the air filter for carbon that would be a sign of engine running backwards.

 

Other than that the transmission needs to be rebuilt most likely.

If it was running backwards it would be the first 12 valve I have ever heard of that did that. The guy driving it is a heavy truck mechanic/welder/fabricator so I believe he would have known if it was running funny. After he got the skid steer off he went to turn around and that was when he discovered no reverse. He did say that it shifted and ran like normal on his 10 mile drive home, but when in neutral or park it still wants to go forward. I am just trying to figure out what is the cause of this is. I know just enough about auto trannies to make it real expensive...........

I don't know where this info came from, but he was told the "forward clutches were welded"..........

I can't in any way address your stated problem.  I likely going to show my lack of knowledge on transmissions on the Gen II Cummins.  I have a build going on which is posted on this site; I am approaching the time I have to get serious about hooking up a wiring harness to my 2WD 47RE transmission.  I thought The 4x4  12V Cummins used 47RH transmissions, am I wrong?  I thought the big difference between the 47RE and 47RH (other than the output for the transfer case) was that the 47RH is vacuum controlled and the 47RE is electronic controlled; am I wrong?  MnTom, good luck on figuring out your problem, I'll be watching.

No vacuum controls on either. The 47RE has an electronic governor, and lockup + overdrive are electronic. 1st, 2nd and 3rd are hydraulically controlled.

 

The 47RH I believe has a mechanical governor and all shifts (excluding TCC lockup) are hydraulically controlled. I'm not sure if that's 100% accurate but it should be close. Overdrive might actually be electronic as well.

Edited March 24, 20196 yr by kzimmer

The 47rh has computer controlled lockup and overdrive. The governor controls the valve body hydraulicly.

 

MnTom. It sounds like internal clutch problems. How many miles are on the transmission and are they miles mainly hard miles, in town driving, towing heavy in town, etc....

From Wikipedia...

 

The A618, later renamed 47RE (electronically controlled governor pressure) is a heavier-duty version of A518 also known as the 46RE (which also has electronically controlled governor pressure, versus the earlier RH version, which was hydraulically controlled). It was used in trucks and vans starting in the mid-1990s. While currently used with some internal changes such as the move from aluminum to steel planetary carriers and an increase in the number of clutch plates when coupled to the 5.9 L Cummins Turbo-Diesel and the 8.0 L V-10 applications, it's still a 727 with overdrive and stronger internal parts. It has an input torque rating of 450 lb⋅ft (610 N⋅m). The 48RE is an electronically governed, ECU controlled, four-speed heavy-duty overdrive automatic transmission, that is stronger than its predecessor, the 47-series.

The base design from the original Torqueflite remains largely unchanged and the addition of a 2-speed output shaft (overdrive unit) that is bolted to the back of the 3-speed transmission has only two ratios: direct (1:1) and overdrive (.69:1). While lubrication to the overdrive unit was a challenge early on, this challenge was later overcome with factory improvements and/or aftermarket valve body kits. The overdrive planetary has six pinion gears (unlike the 5 pinion used with the A518 used with the Cummins turbodiesel) which is often used as an aftermarket replacement for the stock 4 pinion planetary used with the lighter duty transmissions.