[gijohnson]

My Jatco seems to be using only 2nd and 3rd gear. I haven't had a chance to diagnose the electronics yet, but does anyone have any ideas if this is a limp mode?

 

[firemen122]

Did you ever fix this? I seem to have the same issue.

 

[coog]

I can only say that I've had this situation described by many of those who have had their transmissions go bad in their NPR's...one gear at a time until only reverse is left. Good luck.

 

[firemen122]

New tcm fixed mine...

 

[gijohnson]

TCM fixed mine too. However my OD isn't working. VSS sensor on transmission or OD cancel switch problem maybe? It never even attempts to shift into 4th

 

[astr]

There is a FSM for the JR403 here http://daemon4x4.org/portal/downloads.php?dcid=5&p=2 IIRC, it has extensive diagnostics. Also, I remember reading somewhere here that sometimes the TCM gets lost and need to be reset. It then goes through a learning and calibration process that takes some time/miles of driving.

 

[nexxussian]

ATCU (aka TCM) is worth a try.

Pull the ATCU fuse on the left side of the fuse panel in the cab (ATCU something or other, there is another in the group to the right, but that's not it) pull that, count to 10' put it back.

Climb into the driver's seat, turn the key to "run" (note: for this do not start the truck) with the
Trans still in "park" push the accelerator slowly to the floor, then release, repeat 2 or three times, twist key to off.

Make sure the "throttle advance is adjusted all the way off.


The last bit with the foot feed sets the range of the "TPS" so that the trans will not have to relearn that hole driving.

Your issue is notnwhatnI was having that caused me to reset mine.

Got the directions from BobPR, he's on the opposite end of the Pacific from me.

Good luck.

 

[Car buck]

Did anyone find a copy of the transmission manual elsewhere? This one isn’t there or the link is dead/changed. Is the TCU in the dash or ? I saw a bunch of fuses and stuff on the left mudflap.

 

[Michael Osoba]

Did anyone find a copy of the transmission manual elsewhere? This one isn’t there or the link is dead/changed. Is the TCU in the dash or ? I saw a bunch of fuses and stuff on the left mudflap.

It’s behind where the glove box is, passenger side, inside the dash.

 

[Car buck]

It’s behind where the glove box is, passenger side, inside the dash.

The box there looks like the AW4 box from my Jeep XJs