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AW4 problem

C

Colonel Panik

NAXJA Forum User
Location
New Mexico
Could not find the huge transmission write up so here goes, please move to
the right place.

At highway speed the transmission just goes to something like a neutral mode,
Stopping and shifting to any other gear does nothing.
If I turn off the engine and restart everything is great, for days sometimes.

Friends, I am 8 hours from home, I have my tools. Please tell me what to do.
 
Check your fluid. When was the last time you serviced the tranny and replaced the filter/fluid?
 
For starters here is the thread you are looking for.

http://www.naxja.org/forum/showthread.php?t=1053970

Pull the power fuse to the TCM transmission computer and drive it manually in a pinch and to test the hydraulics with out the e-solenoids and computer control powered up. If it does the same thing, there is something wrong with the AW4 itself. Is it under warranty?

If it drives fine, then there is something very odd going on electrically.
 
Ecomike #10 fuse pulled, Now we wait. This problem may occur the next time I get on the
highway or in 400 miles or some other thing.

Thanks for the link and thanks for the quick reply.
 
LOL.
 
Labotomy results

Thanks to Ecomike the now auto-manual AW4 is just fine.

I pulled the fuse that powers the "computer" that talks with the
transmission. After around 1000 miles of driving, 800 at highway
speeds, all is perfect. THANKS Ecomike :thumbup:

The biggest upside to this is 5 more MPG.
 
Re: AW4 Labotomy results

That "The biggest upside to this is 5 more MPG. " is shocking and even hard to believe (or understand). Any clues as to why?

But great news.

Congrats.

So now you know the problem is electrical ......wiring or grounds, or the TCU computer or the solenoids / contacts inside the transmission (easy to reach just drop the pan, but can be tested at the TCU computer wiring area....There is a Transmission bulkhead connector as I recall that could need cleaning and checking for bent pins.....

Colonel Panik said:
Thanks to Ecomike the now auto-manual AW4 is just fine.

I pulled the fuse that powers the "computer" that talks with the
transmission. After around 1000 miles of driving, 800 at highway
speeds, all is perfect. THANKS Ecomike :thumbup:

The biggest upside to this is 5 more MPG.
Click to expand...
 
Last edited:
Well, it went from 20 MPG to 24.8 MPG. My best guess is that I
am hitting better shift points than the AW4 computer? That is just
a wild @ss guess. Everything just seems so much stronger. My
trips involve some serious big hills, really serious and the Cherokee
just goes up real nice.

The next trip will be with little trailer (4X6) and a few hundred pounds
of STUFF. That may tell us more.

Anyone have a chart showing RPMs and MPH?
 
Too many variables, rear end gearing, tire diameter, tire pressure, road conditions, wind, gas quality, and AW4 gear.... versus RPMs/MPHs.
 
I was getting 6 mpg with a defective TPS and O2 sensor. Half of that loss in MPGs, (5 MPGs) was the TPS, 87 Renix, the AW4 side of the TPS was bad, the engine side was fine. The other 5 MPG loss was the bad O2 sensor.
 
Colonel Panik said:
Ecomike What I watch is the highway speed/RPM but it is not all that important.
The XJ is working just great as is and I have to fix some electric stuff and some of
the plumbing.

What kind of performance did you get with the diesel? Was is okay for a daily
driver?

Here is a fun link: http://www.lunghd.com/Downloads_and_Links/Downloads.htm
Click to expand...

Great site, helped me a lot 15 years ago.

I get 34 MPG and use the diesel as a DD only. Not much good around Austin hills with AC on and 4 people in it trying to go from 0 mph up a hill from a red light at the bottom of the hill. Only 64 HP. Lots of low end torque. No good for trailer towing. I bought it for long Houston DD trips to cut my $500/month gas bill.
 
Another 400+ mile trip with about 800/1000 pounds of trailer and stuff.
Transmission works great.

I will get to the elec trouble shooting some day but I love what I have.

Ecomike is the man. NAXJA rocks.
 
That is interesting. Are there any longterm issues with running it that way? I don't know why there would be, but just curious.
 
So your are not using second gear right ? Just bypassing? And getting better MPG??? Interesting.

Colonel Panik said:
Well, it went from 20 MPG to 24.8 MPG. My best guess is that I
am hitting better shift points than the AW4 computer? That is just
a wild @ss guess. Everything just seems so much stronger. My
trips involve some serious big hills, really serious and the Cherokee
just goes up real nice.

The next trip will be with little trailer (4X6) and a few hundred pounds
of STUFF. That may tell us more.

Anyone have a chart showing RPMs and MPH?
Click to expand...
 
I am still curious if anyone else has done this without any long-term issues. I don't DD my XJ much, but if I could just pull a fuse and get some better performance out of it when off-roading, I would love it.
 
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