I have a couple of torque converter/tranny problems that I hope someone can help with. It's an AW4 with 134K. Just bought it 2 months ago and the tranny fluid was possibly original. I've done 3 drain and fills driving it a couple hundred miles between each one. Also have a new TPS which didn't help at all.

First problem is constant. When upshifting from 3rd to 4th, it goes straight into OD. The only way I can get it to use 4th without OD is to give it a lot of throttle right as it's shifting and even then it will only hang in for a second before going into OD. Then on the flip side, when applying throttle to downshift, it goes straight from OD down to 3rd, again skipping normal 4th gear altogether. This happened before and after I did any of the drain and fills.

Second, just for one day only, it decided to start popping out of OD going down the highway. When moderate to heavy throttle was applied it would go back to OD. Weird. This went away and hasn't returned, but at least from that I know that 4th gear can work without OD.

I searched this site and googled and can't find any experiences that match exactly, but lots of potential problem parts that I just don't understand enough about and would like to learn. Any ideas?

 

The AW4 transmissions are controlled with an ECU/ECT using electronic sensors & solenoids, you get the idea. If you have a bad connection to any of the many sensors used to control shifting that could cause problems. Check all of the wiring connections for the trans. control. You didn't say if you were getting any ECU fault codes.

 

I'm not getting a CEL, so haven't bothered to have codes read. Could I have fault codes without a CEL? Any hunch on a specific sensor failure that could give these kinds of symptoms? I can take it to a mechanic if I must, but would like to DIY if I can since it's still driveable.

 

Get a digital camera and camp out near your XJ. You need to get a pic of the gremlins.
They HATE that.
Almost as much as the GFM's

I hate GFM's more than gremlins. Gremlins give up, GFM's stick around especially if they find a viable habitat

GFM- Garage Floor Monster (n) Latin: Fixitus Annoyinutus. A creature that makes it home on the floors of unsuspecting mechanics floor. Feasts upon tools and hardware that mistakingly are dropped onto the floor within its reach. Playful but not harmless, the GFM's favorite pasttime is maliciously re-arranging the mechanics workplace, placing normally out of the way items within the traffic patterns of the garage it inhabits.

 

Caught one!!!! They appear harmless, but oh they find ways to screw with your XJ that you never could have dreamed of!!!

 

Seriously, I may be onto something that could lead me to the real gremlin. I just noticed that my reverse lights aren't working which I've read could be the neutral safety switch. Can the NSS cause shifting problems?

 

Well the switch you are refering to actually tells the computer what gear you have placed the shifter in, not just neutral and reverse.

 

I took out the NSS tonight, cleaned it, greased it and reinstalled. It definitely made a difference. For one, I have reverse lights now. And the upshifting from 3rd to 4th now works as expected meaning that it will actually hang in 4th with moderate throttle before going into OD.

However, when using throttle to downshift, it still goes straight from OD to 3rd. Anyone have other ideas now that I think I've successfully ruled out the NSS for this remaining problem?

 

Dang it! On the way to work this morning it popped out of OD again! It will go back into OD when accelerating, but when cruising at constant speed it stays out of OD. It's like the exact opposite of what it should do. Again, the NSS is freshly cleaned and adjusted properly (starts in park and neutral only.

Is there anything else that can be cleaned or adjusted? I'm going to be towing a trailer next week, so I really need to get this thing working right.

 

I have the same exact problem with my XJ it only has 119,000 mi. on it so i assuming it can be to major, any help or ideas would be appreciated.

 

Just a little fact here......4th is OD and OD is 4th, you don't have a 5 speed trans

 

sounds like you need to adjust your TV cable...



To adjust the TV cable you:
1: Push in and hold the release button
2: While holding in release button, push "conduit" in as far as it will go
3: Release button
4: Rotate throttle to WOT, some people do this with the gas pedal. Others do it from the engine compartment.
5: Hold at WOT for a few seconds, cable should ratchet out a click or two.
6: Your TV cable should now be properly adjusted, take it for a test ride.

Here is another post about it on NAXJA
http://www.naxja.org/forum/showthread.php?t=1015963


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See if that helps...

 

I never said anything about having 5 gears...but, there is a difference between 4th gear with the torque converter unlocked and 4th gear with the torque converter locked, which is what I was trying to describe by using the terms 4th and OD.

Definitely adjust the TV cable as described above (I call it the kickdown cable). That stopped my torque converter from locking too soon because now it senses more pressure at a given throttle position.

If you're also having the problem I was having where the torque converter comes unlocked just riding down the highway, that's probably a TCU on the fritz. Replaced mine with a junkyard unit which appears to have fixed it for now.