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AW4 died

jeepme

jeepme

NAXJA Forum User
NAXJA Member
Location
Dublin California
Ok so driving back from the store last night I noticed the tranny shifting late, then a lot of smoke, and the engine temp shot up to the red. Luckly I was only a few blocks from home so I limped it to the driveway to find fluid speuing from the breather hose but it looked like a strawberry milkshake. So what could of caused this and is the tranny shot. I replace my fluid and filter once a year and thought this would make it last but I did just turn 150,000 miles last weekend. The Jeep is a 95 and most of the info is in the sig. If the trans is shot can I replace it with a newer year trans without any modifications.

Thanks
 
Engine temp shot up, tranny shifting not normally, and fluid that looked like a strawberry milkshake......sounds as if somehow your coolant got in with the tranny fluid (causing the milkshake color). Not sure if it's toast, but i'd be willing to bet so.

Is there any fluid left in the tranny at all? How about engine coolant, any of that left? If so, what color is it?

I have to wonder if something malfunctioned with the tranny cooler...
 
I have run mine out fluid more then once from overheating and it is still going strong. I am betting you have to fix only what caused the overheating. Of course, that could be something in transmission it self and require a rebuild or replacement. If the over heating problem is external to transmission, replacing the fluid should get you back up shifting gears so to speak. Basically, my answer is similar to the others, until you find the reason you overheated then it is hard to make a educated guess. AW4 is robust and can take a good bit of abuse. Just the fact it ran out fluid from overheating, will not normally kill one.

Bill
 
I ll check the coolant tonight. So I could also need a new radiator then if there is fliud in the coolant? With 150,000 on the tranny I am thinking just replacing it would probably be the safest bet?
 
I'd also get some cans of tranny flush and use excess. Use the cooler hose disconnect way to have it pump out fluid, put in the flush and new fluid, then run it in the drive, going through the gears. No driving, just a long time circulating. Then pump out again and fill with fresh. Probably the best, non-invasive, procedure to clean it. Don't run it again until you verify the radiator.

For the fluid changes:
If you run it till the cooler line sputters (you disconnected it), then it takes a gallon back in, it will push out new fluid towards the end of the next run before it sputters, and it'll all be replaced after you top off with just under another gallon (maybe 7 qts in all - it can't get everywhere...). That's ONE fluid swap.

-Skip
 
Yeah, if you have coolant in your transmission fluid the radiator is probably toast and it mixed with the coolant.

That's the only way I could think of why your transmission was acting funny when your engine overheated.....
 
Well looks like the radiater was the culprit. I opened the cap and sure enough pink milky fluid on the cap. So my next question, how strong are the AW4's and is it worth seeing if my tranny can be rebiult or just buying a rebiuld and slap it in. Sorry for the crappy questions I just never had to deal with replacing a tranny.

Jeff
 
Disco the cooler lines from radiator to trans. Do the flush I recommended (a relatively cheap prescription). Connect them together directly (no cooler or radiator) after the flushes and new fluid and take it around the block. Does it shift OK? Then you're good. Now hook it to a cooler.

If it has problems, you go from there. Chances are a good cleaner flush or two will do magic, but get to it FAST! The longer that crap sits in there the worse it'll get! Even just sitting. Maybe run the cleaner into it (double the recommended dosage) with fresh fluid and let it sit until you get to it...

If it doesn't work, you're only out some fluid and cleaner and you won't be wondering if it could have been saved as you shell out the big $$ for an overhaul... ;)

Skip
 
Don't forget to change your thermostat (they never seem to work right after an overheating session) and flush your entire cooling system as well, to make sure all of the trans fluid is out of it!

I've never heard of a problem like this on the forums before. Anybody else? This is quite rare to have the fluids mix in the radiator - I guess you were just so lucky to experience this rare event :) Be proud.

Also replace your radiator before driving around, even with the trans cooler lines disconnected. You'll be loosing coolant still and well, will overheat again.
 
Yes, there's work to be done once the tranny state is confirmed, but this sort of thing happens. This one was kinda dramatic - they usually start slow and go on for a while until the trans is trashed and it's too late, with no real symptoms first... Recently had it happen to my father in law in his new GMC truck. They determined it must have started while under warranty, but it finally killed the trans out of warranty. They worked a deal, but it wasn't free.

And don't drive much, just test, without a cooler in. No highway or rush hour. ;) You could even close off the upper and lower hoses with pvc pipe caps inserted and clamped for the test. Just fill it up through the upper hose first. Getting a new radiator will be required, but I know I'd want to know how the trans is even before that... just the way I am... ;)
 
Ok new radiator is on its way. Just a thought here but could I fill the tranny with fresh fluid ( I have allready poured in 4 quarts at a time and flushed it through until the fluid looked clean with nothing running) then disconnect the cooler lines and have the suction side going to a clean bucket of fluid and the discharge side going to an emty bucket, pull the rear driveshaft, put the tranny in gear and flush it that way. Basically pumping fresh fluid through the tranny until the discharge side is discharging the fresh clean fluid. ????
 
Last edited:
That's probably how they do it at a transmission shop, if they are honest.....Just lift the rear end and let the tires spin. In theory that should work, but you really want to make sure any coolant is out for sure......
 
No no no....:nono:

The 'suction' side doesn't suck... It just dumps the return into the trans. Flush machines PUMP it back in. You also dont' lift the wheels or put it in drive...

Disco the pressure side and point into a bucket.

Start engine, leave in park.

After about a gallon it'll sputter. Turn it off right away.

Fill via the filler neck.

Repeat once, then top off.


EVEN IF it did suck, just laying the hose in a bucket of fresh ATF would contaminate it!!!


And the speed sensor is the one on the flywheel, it has nothing to do with the speedometer... In fact, illegal parking is the only offense you could commit with it disconnected..

-Skip
 
ok thanks for the info
 
skipc said:
And the speed sensor is the one on the flywheel, it has nothing to do with the speedometer... In fact, illegal parking is the only offense you could commit with it disconnected..

-Skip
Click to expand...

What were you reffering to when you mentioned speed sensor?
 
Very interesting. So, how exactly are the radiator, engine coolant, and transmission fluid inter-related?

I know some XJ's came with transmission fluid coolers that were mounted in front of the radiator. I just assumed those without the tranny coolers had no method of cooling the transmission.

Fill me in, here, where am I mistaken?
 
The radiator has a built in transmission cooler....The cooler mounted infront of the radiator just is an "extra" cooler.......aka, both are used and it just cools it better having both.

His coolant was mixing with the transmission fluid inside the radiator due to a crack or leak
 
Blaine B. said:
What were you reffering to when you mentioned speed sensor?
Click to expand...

For some reason, it takes many refreshes at certain times to get a page loaded from this site. So, I started doing multiple threads at the same time. I incorrectly added that while thinking about another thread...

I've been trying to edit it out, but it just won't load. Maybe when 'conditions' are better I will, however now that you pointed it out, this will look odd! :dunno:
 
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