2000 XJ won't shift into OD

I've had my Cherokee for about 9 years now and have recently developed a shifting problem. It take off fine and shifts up thru 3rd without any problems. Sometimes it'll go on into OD, but mostly it won't. A friend suggested putting it in neutral and turning it off once I was going 50 or so. Then restart and shift into D. This seems to work. What's up? OD is obviously functional so why won't it shift up the way it should? Is this a cable adjustment issue, faulty solenoid or what. I'm stumped.:helpme:

CEL on? What does your tranny fluid look like and when's the last time it was changed? Start with the simple stuff then go from there.

Yeah, the check engine light is on. I'm taking it in Monday to get code read. I got about 800 miles on the last fluid/filter change and the fluid still looks/smells like new. No overheating or slippage issues that I can tell. Problem started suddenly. It was working fine when I stopped for gas and shut it down. When I hit the highway again it wouldn't go into OD. 3000+ RPM on the highway kills the gas mileage.

Any P700 code will be a tranny code. Report back if it throws one of those codes. That will narrow it down.

Check the adjustment of the TV cable. It runs between the throttle body and the transmission. If it is out of adjustment, this can happen. There are tons of threads on how the adjustment is made.

O-Gauge Steamer said:

Check the adjustment of the TV cable. It runs between the throttle body and the transmission. If it is out of adjustment, this can happen. There are tons of threads on how the adjustment is made.

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OK - tried that. The cable was already adjusted w/no extra slack. I'll get the cods read in the AM and see if that sheds any light on the subject.

I believe the TPS and NSS are also inputs into shifting behavior. When I had the same issue, it was one of those that fixed the problem...just cannot recall which.

the_weirdo said:

I believe the TPS and NSS are also inputs into shifting behavior. When I had the same issue, it was one of those that fixed the problem...just cannot recall which.

Click to expand...

Ok 'm getting codes PO 132 and 141 which both relate to the o2 sensors. I'm also getting a PO122 which is a TPS fault and a PO705. According to the guy ay O'Reilly's that's a "Transmission Range Sensor." My Chilton's doesn't even mention such a beast - in fact it doesn't even list that code. Any thoughts?:wierd:

Ah yes... The dreaded P0700 P0705 error codes. Those, my friend, say that it is time to remove, clean, repack with dielectric grease, reinstall and adjust your NSS.

It took me all of maybe 45 minutes (I'm old..) to do mine. There is no reason other than the NSS has exploded that a new needs be purchased.

What happens is that over time, the dielectric grease in the switch cooks by the heat of the transmission. It hardens and the small moving contact no linger makes the circuit. When you take it apart, I recommend that a "Scotch Brite" pad be used to polish the contacts. and the Solvent of your choice to completely degrease the unit I will give you a fair warning here, the teeny tiny little spring that holds the moving contact against the non-moving ones like to jump out and run away.

Tons of threads here on that details how to perform this task. Personally, I like to put witness marks on the switch and the transmission to aid the reassembly.

But, here is a way to adjust the switch.
With the transmission in neutral, install the switch so that the neutral standard line (on the case of the switch) is vertical. Make sure the hardware is only finger tight at this point.

There is a vertical groove in the Manual Valve Shaft that will be vertical also provided the transmission is in neutral. Note that some years have a flat instead of the groove. Tighten the switch adjusting bolt to 13 Nm (9 ftlbs). Bend at least two washer lock tabs over switch attaching nut to secure it. Reconnect the shift linkage rod. Reconnect switch wires. Check operation. Engine should only start in Park and Neutral.

Of all of the repairs on our Heeps, this one is about the easiest and it most assuredly saves the most money over purchasing a new part.

Cheers.

Thanks O-Gauge - As it happens, been there/done that. Switch is clean as a whistle & looks brand new inside. The odd thing is, since I was also getting a TPS code I backprobed that and it checked good. Since I was a little dubious about how experienced the kid was who ran the check yesterday & I had to go into town today anyway I had the check run again. Here's the weird thing. All the way to town the darn thing ran in 3rd. When the guy checked the codes, the only thing showing was the one for the rear O2 sensor (bad heat element). I had him clear that. The CEL stayed on, but now the computer is showing "no stored codes" according to their scanner. On the way home and the trip to work & back later in the day, the darn thing goes into OD just like its supposed to but the CEL is STILL on. WTH?? What will cause the CEL to be on with no stored codes?

trans codes are stored in the TCU.

TPS Is the Throttle Position Sensor. It will most definitely cause shifting/ no overdrive issues.