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Transmission/Torque Converter Issues

sean882

NAXJA Forum User
Recently, after driving for about 10-15 minutes at or above 45 mph, my AW4 transmission will downshift a gear (or maybe its the torque converter unlocking - whichever typically engages at 40-45 mph when driving smoothly). If driving at highway speeds, this is accompanied by a sporadic clouds of smoke behind my jeep, very thick. At Advanced Auto, a guy found a little transmission fluid under it, but after checking the levels, it still is in the good range. It does not smell or appear to be burnt. After cooling down for 2+ hours, I can get another 10-15 minutes with the transmission acting normal. Any ideas to what this could be/things to check (and how)? Does it sound like something electronic(TPS, other sensor), Torque Converter, Transmission itself? I thought low fluid might be the cause, but the fluid is not low. Thanks for any assistance, -Sean
 
If you have sporadic clouds of smoke coming out when this happens, I would suspect that the engine is cutting out a cylinder or two. I would pull out the spark plugs and take a look. All off them should be whitish tan. If one or two are darker or a little oily, that cylinder may have problems.
 
Year? TPS could also be suspect. That might explain a downshift, and perhaps the cloud if the engine computer thinks you just floored it.
 
If you found transmission fluid undrerneath the bottom side of the jeep then it is doing what mine did when it downshifts alot at highway speeds and that is the trans fluid is getting so hot it is expanding and bubbling out the transmission dipstick tube which is on the same side of the that the exhaust runs down and as soon as it hits the exhaust it burns up and creates the clouds of white smoke you speak of. If you solve your constant down shifting problem then you will get rid of the clouds of smoke.
 
You need to find out what is smoking, excess oil or fuel, tranny fluid on exhaust, or coolant head gasket leak.

Pull the plugs, see what they look like.
 
Its a 96 AW4.

Ben: That would explain why the tube seemed to be coated in tranny fluid, making it difficult to get a good reading on the stick, and the fluid on the outside of the tube. What did you do to cure your problem?


EcoMike: I know I'm leaking oil out of my valve cover gasket, possibly someplace else? I did find some tranny fluid on the dipstick tube, and on the bell housing. I found something on the transmission cross-member, but it was very dirty and I couldn't ID it. I've been either leaking/evaporating a little coolant fluid since I purchased it a year and a half ago, about 3 quarts per year (15,000 miles). How would I go about figuring out which one is burning? Is there a distinctive color to look for in the smoke?

I'll check the plugs tomorrow.

Thanks for your help!
 
May be time for some careful cleaning with soap and water, but keep the sensors dry!

I am not sure what to tell you on the smoke colors
 
May be time for some careful cleaning with soap and water, but keep the sensors dry!

I am not sure what to tell you on the smoke colors

I like Simple Green cut with water, mix it in a new/clean garden sprayer and got at it top and bottom, then use a garden hose with LOW pressure to rinse it off, trying not to soak the harness where it connects to sensors and joins other sections of harness.

Black--way too rich.

Dark Gray--too rich.

White--head gasket (congratulations, you are driving a Stanley Steamer).

Green--Naw, just kidding, you only get green from a Prius. LMAO!
 
I like Simple Green cut with water, mix it in a new/clean garden sprayer and got at it top and bottom, then use a garden hose with LOW pressure to rinse it off, trying not to soak the harness where it connects to sensors and joins other sections of harness.

That's what I normally do, or use engine degreaser. Last time though I killed the tranny side of the TPS with the simple green and hose. Pretty obvious as it would downshift as I let off the gas. The engine side of the sensor tested shorted, but I think that had been that way for a while and was the reason for the recent crappy mileage.
 
I drained the tranny fluid and replaced the gasket because it was leaking and I refilled it with tranny fluid and it hasn't done it since but since the first time I had it happen I figured out that it would only do it if it was downshifting alot while at highway speeds so I just don't push it to downshift much. So for you I would guess that if you solve your downshifting issue then you solve the problem of clouds of smoke behind the Jeep.
 
Don't forget that the full mark is for hot tranny fluid. I drove mine for 3 years with a bad TPS, and never had tranny fluid overflow, and dips stick showed full when hot. New TPS and it starting shifting at the right speeds, which also got the tranny fluid hotter, and it starting overflowing out the dip stick. :bawl:

I withdrew about a pint. Now it is full, by the dip stick reading, when hot (hotter than before), and does not overflow, and runs fine.
 
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