Hello Everyone. First post here. Hope its in the right spot.

I have a '96 XJ, base model, AW4 (no gauges). The transmission will do quick up/down shifts sometimes. Sometimes it will go into limp mode, stuck in 3rd. Sometimes the torque converter does weird things. I have replaced the TPS, all three solenoids (twice), filter, fluid, etc. I put a transmission cooler on it also. TV cable adjustment also done. I feel like its either heat related, or electrical. It runs fine and shifts fine cold. When it gets hot, it misbehaves. After a short drive today the pan was 170F, the in/out tubes were more like 200F+. I have also replaced the radiator, and flushed it. I believe the water pump is fresh too.

I recently (still in break in period) re-geared the Dana 30/35s with 4.56 because I thought the trans was working too hard with the new 33" tires I put on it. Still acting goofy. But man, love the gears.

Control unit problem (TCU)? The only thing I haven't done is the switch on the gear selector (NSS?) that bolts to the side of the transmission.

Thoughts? Suggestions?

 

Quick up/down shifts like the torque converter is locking and unlocking? If that's the case, look at the switch on the brake pedal. You've already done the TPS, otherwise I'd suggest starting there, although it wouldn't hurt to check it with a meter and make sure the voltages look reasonable.

 

What fluid are you using?

 

Try CCKen's quick screening test for pump and/or converter issues:

 

Valvoline Max Life Multi-Vehicle ATF. Full synthetic. Not ATF4

 

The quick up/down feels almost like it slips out of gear, but I think its downshifting for a split second then going back to proper gear. Only between 1 and 2. The torque converter issue seems to be in 3rd. It just goes straight to lock/low rpm lugging.

 

IMO you're going to have to get rid of all of that and go (back) to Dex/Merc.

 

Which is fine....But its compatible with dex/merc. What would be the issue with this fluid?

 

Thanks. I'll do this in the morning.

 

Just because it says it is compatible with Dex/Merc doesn't mean it's compatible with an AW4 transmission. Do yourself a favor and do a fluid exchange with Dex/Merc before you go chasing anything else. See my sig, #3.

 

Given you've already changed the solenoids and the symptoms seem like solenoid issues, I would recommend cleaning the connectors in the wiring harness. Besides the one on the trans computer itself, there are two in the engine bay on the passenger side up against the firewall. I don't recall, but I think some years also have a 2-pin connector in the wiring on the drivers side of the transmission that leads to the output speed sensor (which hides under the bracket that hold the xfer cae linkage).

If cruiser54 is in earshot, he'll yell at you to check all your ground points too. Especially the ground for the TPS.

 

I did see the bit about checking grounds when I joined earlier. I haven't taken the grounds apart yet, but visual inspection found the whole stud/terminal completely covered in oil and dirt. I cleaned it, but it was too hot in there to get into it. To be continued.

I'll get that fluid out of there as soon as I can.

 

It's possible your TCM doesn't like your 4.56 gears in that the trans output speed doesn't coincide with vehicle speed. When the TCM thinks the vehicle is at a certain speed, the trans shifts up, then the engine lugs so the trans downshifts.

 

The trans computer actually has no idea how fast the vehicle is going. It only measures it's output rpm (and input rpm for 98+) and shifts based on the output speed and throttle position.

 

Yeah. The problem existed pre-4.56 gearing. I've gotten some goods suggestions here and I need to explore those before anything else. I'll check back in once I've taken apart the grounds at dipstick and re-assembled, pumped out all the fluid and replaced with dex/merc and cleaned the harness connectors in the engine bay.