I just picked up a '98 Cherokee Classic with the 4.0 and AW4. The previous owner ran the transmission out of fluid because a cooler line had a hole in it. It sat for 2 years until I got it. I fixed the hole and filled it up and got it driving again.

The problem I'm having is that when the Jeep is first started the transmission shifts fine when it is in D. When it warms up, if I stop and take off it is like I'm starting out in 3rd gear. I can drop it down to 2 and it will take of like normal, then I upshift into D and all is fine until I stop again.

I don't know if it is related, but the back up lights don't come on when in R. The bulbs are new.

 

Sitting for 2 years is a long time might need a little time to get all the stickness worked out of it. At very least id install a new filter and clean out tranny pan then drive more.

 

Check your fluid level.
Check if fluid is now nice and red after that previous abuse.

Check manual shifting: if it shifts fine 'manually', than the problem is in the electrical part of things. You need to now, because the mechanical side of things in your case (with the trans running dry which is bad bad) could still have taken a kick in the n#ts.

If manually shifting gives no issues, next think to check would be solenoids.

 

http://www.pirate4x4.com/tech/billav...AW4_manual.PDF

 

The fluid is clean and red. I just installed all new fluid to get it driving again.

Manually shifting works perfectly. Once I manually shift it out of "2", I shift directly into D and it shifts fine from there (skip the 3 selector).

I've disconnected the TCM and it shifts through each gear manually fine. The transmission does exactly what the link above says it should do with the TCM disconnected.

I've also noticed the backup lights don't function.

My PCM is also showing a P0700 code. Is there any way to read that code without a DRBII?

 

The reverse lights are controlled by the NSS. The grease in them gets thick and the contacts don't touch. Eventually you might also get a 'no start' in park or neutral. They're easy to rebuild. Here's a good 'how to'.

http://www.bc4x4.com/tech/2010/jeep-...ty-switch-nss/

 

TPS sensor or fuse under the dash passenger foot area. Most likely TPS

 

Works fine until it warms up? That's likely a solenoid that's bad, binding when they warm up is a fairly common failure mode. Sitting dry probably didn't help.
The comments about the grease in the NSS and cleaning it are dead-on.

 

So, if you want, you could test them. Or replace straight up.

 

I've checked all the fuses in the footwell fuse box and they are all good.

Is there any way to pull the transmission code without the fancy reader?

I'll most likely replace the NSS if that is the issue. Would the TCM code tell me it wasn't making contact? Every now and then it won't start in P. I have to shift it down to N to get it to start.

 

Most auto parts stores will read a code for you at no charge.


NSS ain't cheap, which is why some folks prefer to rebuild them.

 

I've got the same code reader as the auto parts stores. It won't pull the TCM code. All it will show is the P0700. I'll have to have someone with a DRBII reader pull it.

I'd rather replace the NSS. For the $100 the part will cost, I'd trust that more (already priced it through my account at O'Reilly).

 

It sure sounds like your 1-2 shift solenoid is out of range. If it shifts OK when cold but not when it's warmed up it may mean that the increased resistance caused by increased heat is putting the resistance into the fail range. The solenoids have a narrow acceptable range of 11-15 ohms.

There are other methods to check the resistance of the solenoids but the most accurate way is to pull the pan, unplug the connector and measure the resistance from the solenoid to the bracket.

Be careful removing/adjusting the NSS, they're expensive.

 

There are tests you can perform at the TCM connector to see if the Transmission Range Sensor (NSS) contacts are defective and to see if a solenoid is bad.

You'll need a digital Volt/Ohmmeter.

Refer to the TCM pinout below.

Turn the ignition to RUN, without cranking the engine.

Test the NSS contacts:

Use a Voltmeter.

Shift the trans to 1-2.

Read between pin cavity 21 and pin cav 24, you should see battery voltage.

Repeat voltage tests at pin cav 9 in shift select 3, pin cav 22 in shift select D, and pin cav 18 in shift select R.

If any one of these tests shows a low voltage or no voltage, suspect that the NSS needs to be rebuilt.

Test the Solenoids:

Use an Ohmmeter.

Ignition OFF/LOCK, disconnect battery negative post connector.

Read between pin cav 12 and pin cav 24 as ground. You should see between 11 and 15 Ohms. 1-2 and 3-4 solenoid (A).

Repeat tests at pin cav 13. 2-3 solenoid (B), and pin cav 11. Lock-Up solenoid (C).

If any one of these tests shows a solenoid with out of range resistance, suspect the respective solenoid is bad.

Note that pin cav 24 is the TCM ground at ground G101 on the engine. It's located at the ignition coil attach bracket studs.

 

Thanks! I will take a look at this tomorrow when I get home from work. I will report back what the readings I got are.


I ordered a NSS (I can send it back) that way if it is that I can change it out quick.