lawsoncl

That would be my next step. There is a pressure port on the side of the trans (metric thread as I recall), and the specs for pressure are in the factory service manual.

robsjeep

Today we did the stall test, and lag time test. Both tests passed. No reoccurrence of the slip nor burnt smell. Still dont know what was wrong, why it slipped so much on the trail.
Would not passing these two tests indicate all is ok? The stall test means clutches are good, correct? (at least in drive and reverse anyways)
Can the stall test be performed in 1, 2 and 3 gears?

cruiser54

Are either of your cooler lines smashed or damaged at all?

robsjeep

I believe they are ok, Ill give them a once over tomorrow. Been under there several times since, nothing obvious damaged. Didnt notice any problems, but didnt specifically closely examine every inch of them.

cruiser54

I wonder if there is good flow through the cooler in the radiator.
Any kind of restriction will bring heat, and heat will cause slippage.

robsjeep

I ran my AW4 Transmission stall test, per the factory manual on my 1990 XJ.* My test passed at 2200 rpm, limits are 2100 to 2400 rpm.

The Stall Test is ran in Drive, and in Reverse gears. Among components tested with the stall test are the clutch(es) in the AW4. My question is...
Which clutches are tested when in Drive part of the test? Do all of the forward chutches get tested as the engine revs up? Or is only one of the gear's clutch in play, the only one tested?
I am trying to gain an understanding of how these parts come into play in the AW4. Any insight is greatly appreciated in how this operates, and what components the Stall Test is testing.
Is a passing Stall Test a positive indicator that all the clutches are working, or just some of them?
Can the stall test be ran in 3rd, or 1/2 in addition to Drive and Reverse? Will that test other components not tested when performing Drive or Reverse Stall Tests?


Thanks!

* Interesting side note... my friends 2002 XJ factory manual has no stall test procedure nor limits listed.

cruiser54

I believe that is only testing the converter. It's stall speed. In D at a stop, you're in 1st gear.

robsjeep

Transmission Temperature gage is planned to be added. I will do a pressure test too.

So far issue has not reoccured, i.e. the slipping and burnt smell in cab, but I havent been in low climbing a steep dirt road since, just freeways and around town and it has been fine. We have a few steep city streets up long hills, and it performs ok so far on that too. Maybe I can do those city hills in 2 Low rather than 2 High, to closer replicate the condition when the slipping and smell occured ( was in 4Low when it slipped and smelled, oh and it did shudder once earlier that day for several seconds, never ever did that before, nor since)

Got super hot? The gage will tell that if there is a next time of slip.





Frustrating that I havent found a problem, and it has not reared its ugly head again. I want to know I fixed it so it wont likely happen on a week long overland trip in the middle of nowhere over long rock crawling routes.

Saudade

The stall test is only done in D and R. As Cruiser says, the trans never shifts since you're not moving. You can review the Stall Speed analysis and find out what "passes". There's also a pressure test and a time-lag test.

Section 21 p134 has a good diagram of the clutches, brakes and planetary gears, what they do and how they respond to shifts.

cruiser54

How old was the fluid in the trans when this event occured?

cruiser54

I've merged and retitled the 2 threads on this subject to keep some continuity. AND:

THIS is an excellent write-up by BlueRidgeMark. https://www.cherokeeforum.com/f2/tra...2/#post3203079

robsjeep

Few years old, under 6000 miles. nice bright red color.

cruiser54

Well, they're robust transmissions and do recover.
Did you read BlueRidgeMark's link?
Is it possible the Jeep got the incorrect trans fluid 6000 miles previous? It happens.
The AW4 does NOT use Chrysler fluid. Dex/Merc is what it uses. About 4 quarts per fluid change.

robsjeep

That is the stuff I use, Valvoline dex/merc.

cruiser54

That's great.