transmission issues 98 aw4

Hi everyone,
I've been a member on here for a while and never had any problems with my jeep, believe it or not! My jeeps is a 98 4dr AW4/231 with 4.88s and 33's. I noticed the other day i drove with my a/c on(always run my aux fan with a switch) all day and my trans fluid started to foam out of the filler/dip stick tube. I thought this is abnormal because i do have an inline trans cooler on the outside of my radiator; the trans shouldnt be heating up for no reason... Anyway i dropped the pan and noticed my fluid was a chocolate milk/mocha brown. when dropping the pan i noticed a dark film on the bottom of the pan and the magnets had some shavings on them. i cleaned everything up, sealed up the trans and put fresh dexmerc in it and ran with no problems. Few days later CEL comes on flashing a p0700 and a p0740. Checked the codes and p0700 was tran control system malfuntion and p0740 is torque converter clutch malfunction. So I did SEARCH on here and found a few threads but no relative information.

I erased the code and drove and the CEL with the same 2 codes keeps appearing. I asked a few people and they said it sounds like the trans torque converter solenoid went out. Easy fix. They second time i pulled the pan(maybe 60 miles on the fluid) i checked the fluids and it was a dark red. swaped the solenoids, new trans filter and fluid. Drove for a mile and BAM! the CEL comes on and no change. I checked the trans wiring and everything checksout fine.

Symptoms: NO overdrive. 4th gear does not work. Cruise control does not work neither.
1
Can someone point me into the right direction? HELP! SOS! thanks

:gonnablow:explosion:explosion

Unplug the TCU and drive it shifting manually. You should get 1st in 1-2; 3rd in 3; 4th in D; reverse, neutral, and park. If all is Ok, then your problem is electrical in nature; if not, then the problem is hydraulic/mechanical.

If the problem is electrical in nature do the basics: test the TPS, if out of spec replace. Adjust the throttle pressure cable. Check the fuse to the TCU, should be a 10 amp I think on your year it is in the PDC, not sure. If still no go, then you need to pin out the harness to the TCU to make sure there is continuity.

I agree with Joe's strategy for isolating.

From what I can see by GOOGLING those two codes, (try it, lots of hits on these two codes) you might have an internal problem.

If you can't shake it, I'd consider getting a couple of opinions from tranny shops to see what they say.

birchlakeXJ said:

I agree with Joe's strategy for isolating.

From what I can see by GOOGLING those two codes, (try it, lots of hits on these two codes) you might have an internal problem.

If you can't shake it, I'd consider getting a couple of opinions from tranny shops to see what they say.

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called a trans shop and the guy said the mocha color fluid sounds like water in ur trans. "Basically kiss it good bye because all of the internals are ruined" :smsoap:

The shavings do not sound good to me at all. Use Joe's method to see if you can isolate it down to one subsystem or another.

If it turns out to be broken, don't pay thousands for a rebuild, get a low mileage AW-4 out of the scrapyard (with the torque converter if possible), throw all new seals on it, and jam it on in. You can use an AW-4 from a 98 to 01 and it will bolt up perfectly. I'd bet you can do the whole replacement, with all new fluids and seals and everything, for less than 300 dollars in two days.

So I unplugged the tran computer, drove and manually shifted....1st gear and 3rd gear shifted fine. I shifted to fourth and it felt as those it shifted but didn't drop the rpms down. I'm thinking that maybe the torque converters clogged with a bunch of deposits from the old mocha burnt fluid?

kastein said:

The shavings do not sound good to me at all. Use Joe's method to see if you can isolate it down to one subsystem or another.

If it turns out to be broken, don't pay thousands for a rebuild, get a low mileage AW-4 out of the scrapyard (with the torque converter if possible), throw all new seals on it, and jam it on in. You can use an AW-4 from a 98 to 01 and it will bolt up perfectly. I'd bet you can do the whole replacement, with all new fluids and seals and everything, for less than 300 dollars in two days.

Click to expand...

Going to the scrap yard is the next step if I can't find the problem.

ProjectJeepXJ said:

So I unplugged the tran computer, drove and manually shifted....1st gear and 3rd gear shifted fine. I shifted to fourth and it felt as those it shifted but didn't drop the rpms down. I'm thinking that maybe the torque converters clogged with a bunch of deposits from the old mocha burnt fluid?

Click to expand...

You won't have tc lockup with the TCU unplugged.

mocha as in brown burnt fluid or mocha as in frothy latte fluid?

As the auto trans has clutches there will always be some debris in the pan. Metal filings sounds bad, but that pan may have never been off before in its lifetime.

If it has antifreeze mixed in w/ the ATF, you can kiss the clutches goodbye. Antifreeze eats the adhesive off of the friction discs. And gunks up all the itty bitty passages in the solenoids, and spacer plate between the case and the valve bank.

joe_peters said:

You won't have tc lockup with the TCU unplugged.

mocha as in brown burnt fluid or mocha as in frothy latte fluid?

As the auto trans has clutches there will always be some debris in the pan. Metal filings sounds bad, but that pan may have never been off before in its lifetime.

Click to expand...

mocha as in burnt. i've pulled the pan before replacing the pan gasket. is there a possibility the torque converter clutches are maybe stuck? or sticking?

I dropped the pan on the 99 aw-4 I'll be putting in my 96 soon and it had almost no residue of any kind in the pan. It had 158ish thousand miles on it.

lilredxj99 said:

If it has antifreeze mixed in w/ the ATF, you can kiss the clutches goodbye. Antifreeze eats the adhesive off of the friction discs.

Click to expand...

thats exactly what the trans guy told me.

kastein said:

I dropped the pan on the 99 aw-4 I'll be putting in my 96 soon and it had almost no residue of any kind in the pan. It had 158ish thousand miles on it.

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mine was once like that :hang: it had a dark gray residue (thinking metal). i have bout 165k on the drivetrain

so is this looking more like an electical issue versus a torque converter issue?

Mine was doing that and I replaced the syncros and it worked fine for a while but it eventually bit the dust. Also messing with the NSS cleaning readjusting etc helped out too.

ive got a use torque converter from an 89, will it work with my 98 xj?

ProjectJeepXJ said:

ive got a use torque converter from an 89, will it work with my 98 xj?

Click to expand...

Don't know for sure, the part number 87-90 changed 91+ but it might have been just that--a change in the numbering.

I would check with a local trans shop or dealership.