blue01xj

Ok guys here is what i have:

1998 4.0L AW4 NP242 Limited 150K miles

Was throwing PO700/PO751 trouble codes and not shifting into OD.
Shifts fine 1,2,3 manually and by computer. Swapped TCU's and same thing.

Drain plug was leaking / stripped so I was going to replace the pan so Replaced all three Solenoids at the same time even though the old ones ohm ed out at 13-14.

All back together and fluid good I test drove it and still no OD.
Swapped TCU's once more and still no OD.
Adjusted the TV cable, no OD.

When I manually shift in 1-2 it will shift into 2 at 4K+, then I manually put it in 3rd and it shifts, but when I run 3rd out some and shift into OD the rpm needle bounces like it wants to shift but does not go into 4th or OD

Decided Im done trying to figure it out so had the jeep put on a computer to tell me what is wrong with the trans. They said the jeeps trans will not communicate with the shop computer. Got the jeep back home and looked over all fuses with nothing found.

Bought out of ideas and not wanting to swap trans/torque converter with out knowing for sure that is the problem.

Any Ideas or help is appreciated.....

SG Mason

What year TCM did you use in the swap? apparently the 97 TCM only works with 97 AW4.

Before spending more money on the problem test the TCM as outlined by CCKen in this post

My problem was a P1694 but using CCKen's test I was able to find the problem before spending a cent. It turned out to be the TCM in the long run for me. Now I am chasing a P0705, but I think it is the command start causing the problem since everything checks out.

CCKen

Did you the manual shift test with the TCM disconnected?

Here's some ofthe FSM manual shift procedure:

AW4 MANUAL SHIFTING TEST (FSM Procedures)

(1) This test determines if problem is related to mechanical or electrical component.

(2) Stop engine and disconnect transmission control module.

(3) Road test vehicle. Shift transmission into each gear range. Transmission should operate as follows:

• lock in Park
• back up in Reverse
• not move in Neutral
• provide first gear only with shift lever in 1–2 position
• operate in third gear only with shift lever in 3 position
• operate in overdrive fourth gear in D position

(4) If transmission operates as described, proceed to next step. However, if forward gear ranges were difficult to distinguish (all feel the same), or vehicle would not back up, refer to diagnosis charts. Do not perform stall or time lag tests.

CAUTION: Do not over speed the engine during the next test step. Ease off the throttle and allow the vehicle to slow before downshifting.

(5) Continue road test. Manually downshift transmission from D to 3, and from 3 to 1–2 position. Then manually upshift transmission through forward ranges again.

blue01xj

TCM was from another 98 and one from my 2000 just to be sure so I assume I can rule out TCM.
Thought maybe brake light switch but the 98 only has one, not two as shown in alot of pics about this issue but guess I could ohm out the brake light switch and TPS then volt read the brake light switch to rule those out.

blue01xj

CCKen, Yes tested it with it unplugged at the TCM not at the firewall.
Did everything as it does plugged in...... still no OD.

That was before the solenoids were swapped so will go do it again now and report back.
I read somewhere there was a fuse for the TCU inline but did not see anything. Wondering if that was bad info or for the older xj's.



Thanks guys for the help and ideas so far.

blue01xj

unplugged the TCM under the dash and road tested

• lock in Park - Correct
  
• back up in Reverse - Correct
  
• not move in Neutral - Correct
  
• provide first gear only with shift lever in 1–2 position - Correct
  
• operate in third gear only with shift lever in 3 position - Correct
  
• operate in overdrive fourth gear in D position - NO

Will down shift from 3rd to 1st as required
Don't do anything in 4th so no change when down shifting into 3rd.