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Caught Fire- Now what?


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Hello all,


I have a 1991 Legacy Non-Turbo with an Automatic transmission that has done something I don't understand......


Some time ago my wife tried to go to the store; she started the car, drove down our 1/2 mile long driveway, and turned onto the road.

As soon as she got on the road she says the car started sounding strange.... She said it did not knock, ping, bang, or anything, only that it sounded like it was "breathing" differently than normal if you know what I mean.

As she started to drive down the street, the car did not shift out of 1st gear, it simply went into higher and higher RPMs (up to like 4K) and wouldn't speed up past about 10-15 MPH.....


At this point she heard someone behind her yell out "FIRE" and she pulled over and cut off the car to find a small fire occuring right below/beside the transmission on top of the catalytic converter that is closer to the front of the car.........

The fire was easy to put out and didn't seem to damage anything (it was a VERY small fire which was burning on top of the catalytic converter... it seemed to be occurring as if a small amount of liquid was leaked onto this hot piece of the exhaust system.........


Now the car starts but will not shift into anything above 1st gear and it barely has enough power to drive up onto ramps.....


All fluid levels are fine, none of the fluids seem burnt or have flecks etc, the car has never had any kind of trouble aside from normal maintenance issues before..............


Any Ideas as to what happened and how I can go about diagnosing the issue/ repairing it????


My theory (I have only a very basic knowledge of mechanics however) is that something developed a small leak and a little fluid fell onto the top of the cat thus catching fire......Grandma tells me that the fancy transmission takes pressure in order to work and that a leak in the transmission line would prevent the transmission from being able to shift into a higher gear.......


I'd appreciate anyone's thoughts on this as I want to learn more about how to deal with car repairs and while I have access to tools and super cheap parts, I don't have access to a cheap mechanic to diagnose this problem.... Even if it's something really serious, I can afford to get a new transmission or something if it's needed.


Thanks a lot,

And By the Way- Badass Forum!



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So your transmission fluid level is OK?


Are you able to look under the car and see where the fluid was leaking from or what residue is ontop of the cat? Maybe it was just a plastic bag?


I'd check around the transmission to see if there were any wires burned up in the small fire.


Maybe the wife was driving around with the parking brake up and overheated the tranny and caused a small fire?

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I was in the car at the time, and I'm sure the parking brake was disengaged.....

I have only a limited view of the top of the cat without moving some major things around.... However, it does seem to have a dampish greasy residue on top at the location where the fire occurred. It has become pretty burnt up residue however; I can't identify it as a fluid, It could be anything from tranny fluid to grease to who knows what.


I'll put it up on ramps in the next day or two and try to get a better look at stuff from the bottom (not enough ground clearance to have a peek from underneath otherwise)


The transmission fluid level is fine, it was the first thing I checked....


OH YEAH, one more detail.... When it had the fire a LOT of funky smelling white smoke was issuing from the fire, FAR FAR more than could likely be coming from a foreign object which had found it's way into there.


Also, there was no object or evidence of an object apparent when I put out the fire.

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Hmmm The CV boots seem to be fine, the cvjoint assembly was replaced about a year ago,


No wires seem to have been damaged, In fact, nothing seems to have been hurt by the small fire.


Is there some way that a gauge can be attached off of a T connecting to one of the transmission lines? Is this something that only the kind of fellow who would not need to ask any of these questions could really expect to be able to handle? Oh well- I guess you have to start learning somewhere!


Also; Does anyone know where I might find info as to what model/production year Legacy transmissions will be compatible to just drop right in to this car? Some guy that I talked to from the local scrapyard told me (I think that I'm remembering this right, I'll certainly double check somehow before moving forward) that a 5 Sp Auto Tranny from a 1990,1991,or 1992 only would fit.


If it ends up being critical, I'd rather go with a salvage tranny than rebuilt simply because of the cost (~$280 around here as opposed to 1500-1800 for a rebuild)


Thanks again for the advice yall

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If you can find an AT transmission from a 90-94 Legacy, and even some imprezas will work.

Your trick is to find out what the Final Drive ratio (number of teeth) is on the replacement transmission. The Legacy N/A AT is 4.111.

That way, you won't fry or have to replace the rear differential as well.

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Was the drip on the Y pipe or farther back? If it was on the Y pipe, there's a possibility of it being something else, but I've never ever seen oil get farther back than that and drip/burn. If it's as far back as the cats, the only thing I can see it being is a line that runs past (fuel, brakes) or the tranny fluid. If a lot of transmission fluid is gone, that would explain you getting little power to the wheels.
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I'm sorry, but I don't know what a y-pipe is....The fire occurred on the front cat (I think It's a cat anyway, it looks like one and it's in-line with the exhaust)

I believe this model has two cats, on right at the back, almost at the end of the exhaust pipe and another which is below/behind/beside the tranny.

If it's not a cat, then I have no idea what that thing is; it doesn't seem to have any wires or tubing of any kind going to it, from the outside it simply appears to be a metal casing with exhaust pipe sticking out from either end


Based on the nature of the fire I don't think this extremely smoky fire was caused by gas(VERY smoky, a strange hydrocarbon smell, somewhat bitter, not quite like exhaust fumes but not totally unlike it either)


It was a 'lazy' flame, unlike fuel... and it left a gooey carbonized residue, I'm pretty sure it wasn't fuel because it didn't seem to burn like it and in addition, I can't see how a compromised fuel/brake line could cause the issue(won't shift into higher gear, just goes high RPM with very little power going to the wheels)



I would easily call this as some kind of leak in the transmission or a transmission line/pan/etc if the tranny fluid level was noticeably lower at all, especially considering the nature of the driving issue.....


Does anyone know (sorry for my ignorance here.... I don't really know how to research the answers to questions like this so well yet)

If the tranny works under pressure; Is it under pressure when the engine isn't running(like the tires etc), or is it not under pressure if it is not being used(currently shifting /etc)?


I guess some kind of test of the pressure of the tranny would go a long way toward the diagnosis here..... I know they also make this extremely bright blacklight reactive dye that is engine/tranny/brakeline/etc safe that is specifically for adding to these systems and then trying to more easily identify small leaks. This may be the best option if a leak is detected by a pressure test, assuming such a test is possible anyway.


The car hasn't made a puddle since it's been parked, and I can't seem to identify anywhere where a liquid leaked out..... I guess a pinhole, or maybe some kind of seal/connection which has become deformed could cause a failure to shift in addition to a small leak, but only leak when it's under pressure......

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Your transmission is not under pressure when the car is off. The flywheel turns a torque converter which acts like a pump pumping fluid throughout the trans. A rather likely culprit is a thing called the kick down valve. When your car comes to a stop this valve literally kicks the transmission down into first gear so it's ready to start driving again. It's a vacuum controlled valve and if the seal in it is gone, it will atually start sucking transmission fluid into the intake side of the engine, which would cause a rather large white cloud coming out of the exhaust pipe. I don't know where it would be on your legacy as mine is a MT and the only other car to do this to me was a late eighties chevy celebrity. But it is a possibility and it may not allow the car to shift either way. Just my .02
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I wish I knew more about auto trans to help more here, but all I've ever driven and worked on has been standard 5 speeds :(.


I'm still leaning towards the fire being from tranny or gear oil (does the center diff on the 4EAT have gear oil?) but how that can be related to not shifting up from first I do not know. A dead speed sensor would cause it, it could be just a coincidence that you got the fire at the same time. You could get it on stands, grab a multimeter and a haynes manual, and find out how to test for a bad speed sensor.

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