overheating AW4???

95XJ, 4.0L AW4, NP231, chry8.25(welded)/D30, 3" lift, 31's.

so yesterday i was at a snow run, and took my little cherokee through course that i probably had no business being in. it was one of the more difficult courses i've ever been around with rocks the size of my tires and bigger and 2 feet of snow. well after i finally made it out of that course my tranny was acting real weird.

in 2wd, it wouldn't move. in 4hi it wouldn't move. in 4low it would drive. in 2wd and 4hi, the engine would just rev and rev but it wouldn't move.

so i got it back down to the parking lot and started looking it over. the shift linkage was fine and going through all the t-case gears. then suddenly i noticed that if i was in 2wd or 4hi, it would start to roll if i reved it up to about 2,000rpm. so i started checking all the fluids and everything, and they were all full.........BUT.....the tranny fluid was FUBARED. i haven't seen tranny fluid that burned in a long time. so i let it sit and cool down for about 1 hour and then decided to try and drive it home. about 10 minutes after jumped on the highway, the tranny started seriously improving.

so here's my question............is it actually possible to overheat the transmission to where it almost quits working, but when it cools down it works fine again???
on the way home (2hour drive), i stoped at the in-laws and stayed there for about 3 hours, and then finished the drive. when i started up the cherokee and took off, it was acting completely normal again.

i'm gonna try to disconnect both lines on the tranny, and stick the output in a 5gallon bucket, and the input line in a 5gallon bucket with fresh tranny fluid, and try to run a few gallons of fresh fluid through the tranny and get it flushed really good.

PS: does anybody have any recommendations for a good quality tranny temp gauge, and additional cooling, or will any trans temp gauge from the parts store be sufficient???

Don't know about your tranny issue's but I know that the AW4 hates to get hot.

I'm running a B&M temp guage on a Autometer pillar pod. My cooler is the Hayden 30,000 gvw unit.

I have this same set-up on all 4 of my XJ's

i'll have to look into that.

any ideas on what the "normal/optimum" operating temp for the tranny is???

do you run your cooler in line with the radiator or by itself???

I run it in line with the radiator, my sensor is on the return line. My normal operating temp is 160. The best overall set-up is to run sensors on the return and output line and use a toggle switch to check both sides.

I really don't worry about what temp is comming out only that i'm putting cool oil back in.

You can find everything you will need at Summit racing. The pod is made for the 84-96 XJ's.

oh one more thing i forgot to mention. i replaced the tranny fluid yesterday, and struck gold. the container i used to catch the fluid in, had a perfect coating of "gold dust". sssssooooooooooo...............which part of the tranny turns into "gold dust" when you destroy it???

any ideas/suggestions as to what i should do with the tranny, or if it's even saveable??? i'm basically already in the market for a new tranny.

in addition to that, i'm going to add a seperate tranny cooler in order of tranny--cooler--radiator--tranny, and then i'm going to install a temp gauge with sending units in both the outgoing and ingoing side of the tranny.

i keep reading and hearing that AW4's are near bombproof from the factory. but aparently i make my jeep work for it's dinner, and it's not liking it. any future upgrades/improvements/changes i could do to the new tranny install/maintenance to help it stay alive???

Blow some air backwords through the tranny cooler. Double check your TV cable adjustment.
It would be be a bumber to install a new tranny with a partially plugged cooler line. Ask me how I know this.:doh:

The glitter in your fluid is the remnants of your clutch discs. You slipped the clutches in the tranny and that caused the overheating. You may get by on the road for a while with it, but you either need a replacement or a rebuild.

is there any way to prevent the clutches from slipping when doing a long uphill slippery obstacle???

drop it down into 1st gear, and try and be easy on the gas but if you have to give it a brake once your up let it sit for like 5-10mins
-keep jeepin

It's normally not a problem on a correctly functioning tranny. When they get old and tired, that is when this sets in. The same thing would have eventually happened on the street, you just stressed it more and quicker.

ok, so i got a "new" (to me) tranny getting delivered tomorrow, and i'll probably install it after work along with a secondary cooler and temp gauge with sending units on the inlet and outlet of the tranny.

i was thinking with going the tranny-cooler-radiator-tranny route, but had a couple questions about different setups.

1)for the guys that completely bypassed the radiator, do you ever have any problems with undercooling the tranny during the winter???

2)what is the problem with undercooling the tranny??? pros/cons???

3)is there any benefit to bypassing the radiator and using a stand alone cooler???


i kinda like the cooler then radiator idea, because that way the cooler can do it's job, and the radiator can either bring it down a little more, or "pre-heat" it a little if it's to cold. does that line of thinking make sense???

update...........toasted new tranny yesterday at the insane cliffs terrain. not as bad as the last one, but i did.

this time i'm completely bypassing the radiator, and using an almost radiator size tranny cooler as a standalone with brand new lines relocated about 1.5" in front of the radiator with some possible fan options.

i'd like to convert to a manual, but i got spoiled not having to worry about the clutch.

I bypassed my radiator last year. Installed a 33kGVW cooler. 17"x11"x1.5"
Installed a filter with sensor port on the return line. Trans temp only hit 190 once when in drive on a fire road for an extended period of time.

Don't drive the rig on the street, so can't comment about under cooling the AW4.

If you wheel the AW4, you need an external cooler and gauge. especially if one is running short or near stock gears. My Opinion.

well i did install a cooler and gauge with the new tranny, but apparently that wasn't enough. so on to try number 2.

i'm sure my wife is loving me right now. 2nd tranny in 3 weeks. and the next event is 2 weeks away. LOL

When you run a cooler in conjunction with the cooler in the radiator you should run trans to radiator to cooler back to trans. This way the radiator starts to cool the fluid before it goes into the cooler rather than heat it after going through the cooler.

Ok, so i've made some changes, and i'm still having problems. i was hoping i could re-use this thread instead of starting another "overheating" threads.

95XJ, 4.0L, AW4, NP231, D30/chry 8.25 with 3.55gears, 31/33" tires (depends what size i wanna run at the time)

BRAND NEW LINES, dual temp sending units (in/out), moved tranny cooler forward 1.5", seperated tranny and engine cooling (tranny DOES NOT run through radiator anymore).

now the tranny temps are better, but not good. on the highway it runs a nice 180-190HOT, and 130-150 on the return line. in the city or pulling off the highway, it'll hit around 210 for a while and then slowly come back down.

on light offroading, it stays around 210 with peaks around 250+.

i'm so running out of ideas. there is nothing else i can do other than add a bigger and bigger and bigger tranny cooler. but that doesn't make sense. i'm not the only one running the AW4, so why am i having nothing but problems with this, and see other cherokee's running around me like it's nothing.

Re-gear or reduce tire size.

currently in the works. building a rear D44 for it, and re-gear the front when it goes in.

really think that's the only problem though??? i mean the 31's shouldn't be that hard on it should they???

Going to commit some serious thread necromancy here as I searched and this thread pretty much spot on describes my transmission's behavior... Drove for about 45 minutes on the highway at normal traffic speeds, got off the highway, first stop light I had the same lack of forward movement except if I hit the gas pedal way too hard. Limped it out of the intersection, parked it for about 5 minutes on the side of the road idling while I scratched my head and poked around under the hood, limped it further down the road till I got to an auto parts store, parked for 5 minutes idling. Checked the fluid level (about a quart or two high :scared: and extremely burnt :scared:, just like scorpio_vette's), shut it off, went inside to see if the techs had any idea what was up... came back outside, started it back up, and it was back to almost-normal. TC lockup doesn't seem to be happening when I expect it to. Went to look at a house I am considering buying, drove home, was acting almost normal... I'm just hoping I don't have worn out clutch plates.

I'm thinking I should probably drop the pan, flush the transmission (Dextron III/Mercon right? not ATF+4?), and hope I don't see gold colored clutch dust anywhere. Anything else I should do?

No CEL was indicated, I didn't feel any rough shifts either. It maintained 75mph just fine on i190 coming home, temps weren't too far out of control, I don't think it went above 210 or 220.

EDIT: further possibly-relevant information - I've been having extremely occasional TPS and/or IAC issues, I haven't had them in quite some time (they only show up right after start, and disappear after 10-20 seconds). I also just finished installing my 2-3" lift and this was the first trip over 30 miles or so that I've done. I suspect this pushed the transmission over the edge into overheating, but I'm not sure.