AW4 hesitant shifting out of 1st, slipping 2-3rd

Like the title says, my AW4 is not wanting to shift out of first on its own (for about a week) and today it slipped going from 2 to 3rd.

a little background:
95 XJ, 4.0, AW4, 231, D30, 8.25 (both with 4.56s), 203,700 miles.

everything was working fine until memorial day weekend. on friday after work i noticed a large pool of coolant under my front pass side. after tearing the header pannel off, i discovered a 2 3/8" crack on the brass band that connects the cores to the plastic endcap on the radiator. she had been running slightly warm so i took the opportunity to upgrade to a CSF 3 core. it took till tuesday for my order to be processed and i finally got my new rad on monday following memorial day. i took advantage of the down time to get some projects done on her- rear disk brakes ZJ proportioning valve, KJ ebrake cables and a 39 tooth speedo gear. i finally got the radiator all installed, filled and ready to start it up to circulate the fluid (i also did a flush prior to installing the new rad). it didnt want to turn over. turns out that my alternator had siezed for some reason and wouldnt turn at all, in fact the pully sat asque and the battery was dead after sitting for two weeks. so i took advantage of the opportunity again to upgrade instead of going stock. i put in a 136 amp alt for a 97 zj and charged my batt.

the problem of not wanting to shift out of first started on my test drive following the above mods/repairs. it will not want to shift out of first gear on its own untill 25 MPH under extremely light acceleration (the kind where old granny would zoom by and flip me off). anything faster than that and it wont want to shift on its own without my help. if i momentarlily let off the gas when speed is between 20-25 MPH then gently reaply the throttle, it will shift to second then shift fine after that. except for hard accell- i tried to speed up where the lane adjacent to me ended and the car behind and to my left wanted to "pit" me. uppon applying aggressive throttle, RPMs shot into the red and the tranny felt like it downshifted back to first on the freeway on ramp! a temp release of the throttle and it behaved normal again.

today i was coming home from work and the temp on the overhead consol read 115*(a "warm" day here in AZ). i turned right from a side street to a residential street. the tranny stayed in 2nd through the turn but when i reapplyed the throttle, i had nothing except coasting for about 50-100 feet, then i had power again. now it barely feels like its slipping between 2nd and 3rd gears.

tranny fluid was a little low following the rad swap, so i added some more Dex III (NAPAs house brand). i ended up slightly overfilling it so when i went for a little trip with 45 min of freeway driving, it started to spew out leaving a white cloud behind me. the trans fluid is dark and in need of replacing, but i now have to drop my tnt belly pan to drain it (coming this weekend with AA SYE)

the xj is my DD, but i do have another vehicle. i just dont like to drive my truck at 12MPG. so the sooner i have the xj back up and running, the better

thanks
stewie

mine does the same thing once in a while, I just shut it off and give the throttle position sensor a good whack with the end of a skrewdriver and then everything goes back to normal, I replaced the tps twice but both new ones caused a very erratic idle so I went back to the original stock one.

Pull the NSS, clean the crud out, add dielectric grease, reassemble and re-install.

If I start up my 96 after having the battery disconnected and let it idle for very long. The shifts get strange. I've learned to connect the battery and drive off on my test drive and not let it idle for long.
If the other tips don't work out for you, try disconnecting the battery for awhile, then taking it for a drive, without the idling.
It's also possible you got coolant in a connector someplace, coolant conducts pretty well and will cause electrical leaks to ground and other gremlins.

i did let it idle up to operating temps prior to my test drive to make sure the new radiator was ok. tonight i disconnected the batt for about 30 minutes and reconnected it. the test drive that followed had no improvement. i then popped the hood and tapped the TPS with a screwdriver handle and did another test drive. no improvement. im trying to stay out of the heat as much as possible so im trying the easy stuff first.

im gonna disconnect the batt tonight and reconnect in the morning when i go to work.

if that doesnt work, ill try to clean the NSS. by the way, i tested the NSS by trying to start the xj in each gear and it passed by starting only in park and neutral.

the torque converter is functioning as i see a slight rise in rpms when the brake is applied just enough to trigger the lights when at cruising speed.

The range selector signal goes through the NSS. Not starting in gear only means the safety portion of the switch is working.

It sounds like a typical TPS problem. You didn't perhaps pressure wash the engine to get rid of the coolant leak did you?

Im sure you checked to make sure there are no pinches in the cooling line to the radiator. make sure you dont have any broken wires or rubbed wire that could be grounding out.

Adjust the throttle cable. Next, take off the hose above the throttle body and then depress the throttle to wide open throttle (WOT). Check to make sure that when you depress the throttle cable all the way you are at WOT. If not, then adjust the throttle cable again.

This is a simple five minute fix that saved me from wanting to rebuild my AW4.

i didnt know that the nss did so much. thanks for the info Frank. i just picked up some electric parts cleaner and dielectric grease and i will clean it after she cools off (perfect time to get some welding in)

i did wash some of the engine when i had her appart. i didnt pressure wash it though. i sprayed areas with simple green and used a toothbrush and rag and rinsed with a garden hose with no extra pressure completely avoiding the TPS area.

ill check the throttle cable for any extra slack too.

thanks for the imput everyone
stewie

I finally replaced the TPS yesterday with a Delphi (C#SS10482, IO#SS10482-11B1 listed on the package) sensor from NAPA. I took it for a test drive and I had the same issues. I did some searching and found a post by 5-90 describing how to test the TPS- new one tested good. I disconnected the battery for an hour and fourty-five minutes. Reconnected and took it for a test drive and same results.

Since then I drove to work and home (totalling 10 miles each way, engine was at normal operating temps/ key cycle) and she's still doing it.

oh, and about 3 weeks ago I drained and filled the AW4. Fluid was dark red, and had no distinct odor (unlike fresh tranny fluid). I did not notice any particles in the fluid. I refilled it with NAPA brand dex/merc III fluid.

I did some searching last night (where I learned to test the TPS. searched 'tps test, transmission and throttle position sensor) and Im still a little lost. I have a pretty good understanding of mechanical things, yet electrical escapes me.

I want to get this taken care of so that I wont have to worry about it anymore. I have lost confidence in my xj durring hard acceleration, and I hate it reving up in first gear until 20+ MPH. Plus I get some dirty looks even from cops.

Thanks
stewie

ok, after some more searching, i seen to unplug the TCU and shift the tranny manually to check if its electrical or mechanical problem. when starting forward movement with the gear selector in 1-2, it will stay in first. i took it all the way up to red lining at the first mark above 5000 RPM. once started i can shift into 3rd, but i think its totally skipping 2nd. I can downshift from 3 to 2 and get second gear.

after that test drive i plugged the tcu back in and went for another test drive to make sure i could still have a halfway reliable way to work in the morning. Im still having the stuck in first issue and can get it to shift into 2nd by briefly letting off the gas and then back on. after getting in 2nd it seems fine unless i have to rapidly accelerate such as on a freeway onramp.

I had a golly-gee-wiz moment. I had it in D and started from a stop. it still wanted to stay in first. i wondered what downshifting would do so i put in into 3rd. it took about 5-10 seconds and after much hesitating and feeling like it was slipping, it went into second and then third a couple seconds later. I intermitantly get the same responce when starting out in 1-2 and then upshifting to 3rd, and others it will shift right into 3rd, or so it seems.

I then went on a side street and was able to shift in and out of 2nd by alternately shifting between 1-2 and 3rd. and the shifts have only a slight hesitation.

Trans fluid is light and full. also no unusual odor- smells mildly less pungent than the new stuff.

so im thinking that its mechanical at this point. it realy sucks too cause i have the tnt y-link and I had to drop the belly pan to drain the old trans fluid out. so i would have to drop it again to drain/fill again or drop the trans pan.

any thoughts or ideas?

TIA
stewie

You could try a valve body before ripping out the trans, But it sounds like an internal seal issue.

Unless I missed reading it somewheres in any post in this thread....
Did you check the trans fuse in the fusebox under the drivers side and then the one that is near the TCU?
I had some of the same issues when I bought mine and the fuse in the fuse block was missing. That's where I started on the road to fix my problem.

Draining and refilling the tranny only replaces about half of the bad fluid. Short of pulling the valve body or tranny for repairs, you could try this. Add a can of TransX, drive it about 10 to 20 miles before draining and changing the fluid again. The when you change the fluid, this time use a quart (or pint?) of the real thick Lucas Transmission leaks sealer additive to see if it will help the internal seals seal batter, so it can shift normally. If that fails I'd say its time for mechanical repairs.

Did you ohm test the three electric shift solenoids yet?

FordGuy said:

You could try a valve body before ripping out the trans, But it sounds like an internal seal issue.

Click to expand...

didnt think of the valve body... wait, im not too familiar with transmissions. i will have to do some searching.

B.RAIDER said:

Unless I missed reading it somewheres in any post in this thread....
Did you check the trans fuse in the fusebox under the drivers side and then the one that is near the TCU?
I had some of the same issues when I bought mine and the fuse in the fuse block was missing. That's where I started on the road to fix my problem.

Click to expand...

i did not check the trans fuse in the fuse box under the drivers side dash. i have no referance chart as none is posted arround it and i dont have the owners manual. and for the fuse near the TCU goes, i traced the wire bundel from the TCU as far as i could until it disapeared into the dash innards and i did not find a fuse. i presume it would then be under the hood in the PDC box. i will have to see if i can dig up my old cover for it. it broke and i replaced it a while ago off of a slightly older xj- cant remember if its on there or not.

Ecomike said:

Draining and refilling the tranny only replaces about half of the bad fluid. Short of pulling the valve body or tranny for repairs, you could try this. Add a can of TransX, drive it about 10 to 20 miles before draining and changing the fluid again. The when you change the fluid, this time use a quart (or pint?) of the real thick Lucas Transmission leaks sealer additive to see if it will help the internal seals seal batter, so it can shift normally. If that fails I'd say its time for mechanical repairs.

Did you ohm test the three electric shift solenoids yet?

Click to expand...

I will have to run out and get some TransX and the Lucas Transmission leak sealer at NAPA tomorrow. its worth a shot. and it looks like i will have to search about ohm testing the shift solenoids.

Thanks for the imput thus far. I will have to work on it this weekend. I will keep posted.

See post # 5 at

http:///www.naxja.org/forum/showtread.php?t=910434

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