Wabatuckian

Hello,

I have codes

P0731 - Gear 1 Incorrect Ratio
P0846 - Transmission Fluid Pressure Sensor / Switch "B" Circuit Circuit Range/Performance

Previously, the Jeep would die when I'd shift it into Drive or 1.

Pulled the TCM relay to force limp mode. It drove in 2 and 3 (manually shifted.)

Added tranny fluid because it was low, at about the same time I pulled the TCM relay.

After driving it a while to test a couple of unrelated repairs (TPS and MAP) I checked the fluid level again, in case it had settled.

Bone dry stick again. No leaks -- someone just didn't fill it up it seems.

Added another quart.

Reinstalled TCM relay. Was able to drive it by shifting transfer case and tranny to N before shifting transfer case back to high and selecting gear.Someone, somewhere, asked me about this.

Will be checking tranny fluid again shortly, but was able to get the codes above.

Items:

1. I most definitely switched to 1st gear at least ONCE while cycling through the gears. However, this didn't happen during driving evaluation.

2. I ordered a junkyard TCM. No guarantee it's good, I guess, but don't want to blow money on a rebuilt if that's not it. Is there a way to test these? Can Chrysler?

3. Is there any way this might be the speed sensors?

I can diagnose all day long. However, I've been out of the Jeep game since the early '00s and don't know the drivability symptoms associated with the codes. You folks are the experts.

Any help would be appreciated.

Regards,
Josh