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Going Through a Beater XJ 4.0.

Interesting info on the switch for the torque converter, Mike. Since you said yours appeared to be out of adjustment, do you think this is an indication that it'd been replaced at some point and not set up correctly, or that it may have "drifted" out of adjustment?

Since the 'threads' on the switch were not damaged that I could see, it seems to me that the switch was just not adjusted correctly. The 2 clicks I heard were well defined, so I don't think the threads were worn. Previous owner wasn't mechanically inclined. So I doubt it was replaced.

The rpm drop at 1700 is 500 rpm. The tc will stay locked clear down to about 1100 rpm at steady throttle. That could amount to some serious fuel savings. The tc stays locked in 4th and 3rd gear. Learned a lot from the online fsm on the aw4.

On the first start in the morning, the trans won't go into reverse. So we'll see if this relates to that at all. Also found out that the trans can throw a trouble code unlike the engine computer. The mt2500 can read it. Saw that on a video from nickintime on youtube.
 
The biggest clue I had was that the mt2500 kept showing the that the brake pedal was pressed. No it's showing it's not pressed, until I press it.

Also learned from the fsm for the aw4 how to test it mechanically only by disconnecting the trans computer. Reverse worked in the morning then. Then the entire trans only shifts manually. So the issue appears to be electronic. I'll see after several more morning tests if any of this holds true. The mt2500 really helped !!
 
Sounds like that was PRESS-ing problem you solved.:D

I think (but my memory is foggy on it) that reverse is purely mechanical.

The 4 forward gears are controlled electrically (TCU) by switching 2 electric solenoid valves, 1-0, 0-1, 1-1, and 0-0 or something like that and the third electric solenoid locks and unlocks the TC. So there is no electric control for the reverse gear. I fixed my cold morning no-reverse for 2-3 minutes issues with a 1/4 pint of trans-X, and several transfusions of fresh fluid for 10 years.
 
So far just fixing the lockup switch on the brake pedal made all of the difference! Each morning it goes into reverse normally and the torque converter locks up !!
 
Where is the Like button? LOL :laugh:
 
One new ac hose and a new ac pressure switch made the ac ready for leak test, evacuation and new R12 freon. Aux fan comes on with the ac. Temp gauge stayed far below 210 even bombing around the dry wash!! Seems all is well after the test drive on an 80 degree day. Monday the xj will climb the pass into town to see if the highway speed overheating is better. 80-88 degrees forecasted all week.
 
Re: Going Through a Beater XJ 4.0. Cooling Issue Cured !!!

The cooling issue is now cured on our '88 xj 4.0, thanks to the new fan clutch. Pulled the same pass at full throttle much of the time, with a passenger, 120lbs worth of batteries, and the AC was running full blast. Don't forget the new over sized fan clutch. Outside temp was 85F, which is 25 degrees higher than the last time I charged this pass, with the temp gauge hitting the red. The temp gauge this time hit about one needle tip width past 210. Didn't have the mt2500 along for an exact number. Cooled right down on the other side of the pass. The old girl did great under full load !!!
 
Refurbed the NSS this morning. Hopefully starting in park will be fixed, and reverse will engage when cold more reliably.
 
Re: Going Through a Beater XJ 4.0. NSS refurb worked !!

The NSS refurb sure paid off !! Reverse works every time and so does starting in park after 17 days !!!
 
Re: Going Through a Beater XJ 4.0. NSS refurb worked !!

The NSS issue was keeping it from going into reverse?

I never thought was possible. I was under the impression Reverse was purely mechanical/hydraulic, bypassing all the electronics? Or do you mean reverse lights?

I always got my reverse working in cold weather by adding a 1/2 pint of trans-X to the Dex III, until the o'rings on the accumulators failed from age and wear.

The NSS refurb sure paid off !! Reverse works every time and so does starting in park after 17 days !!!
 
Re: Going Through a Beater XJ 4.0. NSS refurb worked !!

The NSS issue was keeping it from going into reverse?

I never thought was possible. I was under the impression Reverse was purely mechanical/hydraulic, bypassing all the electronics? Or do you mean reverse lights?

I always got my reverse working in cold weather by adding a 1/2 pint of trans-X to the Dex III, until the o'rings on the accumulators failed from age and wear.

That is correct. Reverse gear has now worked perfectly, every day since the nss refurb.
 
Re: Going Through a Beater XJ 4.0. NSS refurb worked !!

That is correct. Reverse gear has now worked perfectly, every day since the nss refurb.

I wonder if it was linkage or the NSS electrical that caused it. Could it just be that the weather is no longer cold enough for now? Mine was always coldest winter morning start up issues till the Tranny fluid warmed up on the reverse issues. TRans-X always fixed mine, plus transfusions to fresh fluid to clean out traces of varnish in the valve body....

What is there in the NSS operation that even cause a reverse issue, I was under the impression you cut power/fuse to the NSS (once the rig was running), or disconnect the NSS and still get reverse gear?
 
Re: Going Through a Beater XJ 4.0. NSS refurb worked !!

I wonder if it was linkage or the NSS electrical that caused it. Could it just be that the weather is no longer cold enough for now? Mine was always coldest winter morning start up issues till the Tranny fluid warmed up on the reverse issues. TRans-X always fixed mine, plus transfusions to fresh fluid to clean out traces of varnish in the valve body....

What is there in the NSS operation that even cause a reverse issue, I was under the impression you cut power/fuse to the NSS (once the rig was running), or disconnect the NSS and still get reverse gear?

No matter where the shifter was carefully moved to, reverse didn't work on the first start of the morning. Same with starting in park.

I did remove the fuse and got reverse back to mostly normal a few times.

With 7 wires on the NSS, I can imagine it's heavily interconnected.
 
I read today that old power steering fluid can foam, and thus damage power steering pumps. A light went off when I read it.

"All my experience tells me it is cold morning Tranny fluid that needs to warm up for reverse to kick in. Problem is varnish forming. Dex-III has a short life. Needs 3 quart transfusion frequently and a 1/3 pint every winter of Trans-X to solve the problem. About 15 years with two AW4s with that problem taught me this"
 
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