[Tina]

I just purchased a 1990 Pontiac Transport on July 15/03, I test drove it and didn't like how the brakes felt so the salesman got the mechanics to put new brakes and rotors in the front but actually, it was new brakes and calipers. I have had the vehicle checked by three different mechanics in town and they are stumped and I am out of ideas & $$$. Heres my dilemma, It started making this noise like a belt needed to be replaced (been there done it!) Brand new belt and the mechanic said it made the noise even with the belt off? He can't figure it out and believed it to be my Transmission but I did that too.The Transmission seems fine according to the Transmission specialist in town. He thinks it's the Tension Pully but again with the belt off the mechanic says no way. Any ideas it continues to squeal, when you first start the car and when you give it gas and sometimes it will disapate and you think it fixed itself but no luck?

Now another strange thing with this vehicle that no mechanic in town can figure out ( I know, I know, where the hell do I live!) but seriously, I had a pedestrian run out on the road, while I was driving to work and had to quickly slam on my brakes. Well the next thing I saw was the biggest cloud of white/grey smoke I have ever seen, Like I couldn't even see the car behind me. I think it came out of my exhaust and it smelled of old catalytic converter.It's not oil as there is no traces of any oil in the hoses or engine leaks or underneath and the converter is 13 years old. Now when I go to show the mechanic(s) I just quick brake and sure enough like a genie, theres the smoke. The mechanics are stumped on that one too. They say they never seen anything like it, so I told them I was going to start hanging out with the guys who do those smoke shows in town and bet money, that I could out smoke em!@ sincerely frustrated Tina

[87442lover]

Since I seem to be the only forum dweller here at the moment.

So your saying your car starts smoking when you slam on the brakes? Right? Get someone to check and make sure its coming out of the tail pipe (dont know where else any massive plooms of smoke would come from) It's is NOT the tranny, the transmission can not blow out smoke from the exhaust, there is no physical connection anywhere for that to take place. Have you tried using some RXP gas kicker, or other de-carbonizer? Some more details please.

[Indian]

The tranny can blow smoke out of the tail pipes. A faulty modulator valve can burn the tranny fluid up making a dense white cloud.

[woodz428]

I'm gonna take a stab at what it may be, could be a few ,but with the provided info it leads me to one thing (if that's not it and you post again with some other variables we'll work from there. You started with poor feeling brakes, and then a squeal (whine) and now when you hit the brakes it smokes. I would suspect a few things,all right at the master cylinder vacuum booster area. With it is as old as it is when the calipers were replaced it probably put a load on the aging master cylinder, when the brake pedal was low (I believe probably what you weren't happy with) it was over extending the booster diaphragm, the combination of a leaky master cylinder (being sucked into the booster) probably ruptured the booster diaphragm and causes the squeal and also the smoke (brake fluid). Check to see if your master cylinder is losing fluid and if there is any trace of it running down between the master cylinder/booster. But I suspect it is in that area.Keep us posted.

[jimfulco]

I think Woodz is on the right track. For another check, pull off the vacuum hose from the brake booster & see if the inside of the hose has any brake fluid in it. It shouldn't.

[roys63]

I agree with the brake booster , i have seen them fill to the check valve, someone run a leaking master cyl for a long time and just kept adding fluid?

[87442lover]

Originally posted by Indian
The tranny can blow smoke out of the tail pipes. A faulty modulator valve can burn the tranny fluid up making a dense white cloud.

Please explain how? The modulator valve is not connected to the exhaust system. If you see gray smoke coming from the tranny than its coming out from a gasket somewhere, NOT the tail pipe. It's just not possible.

Please think of HOW it would be possible for it to do that first.

I am NOT mocking you or anything, but I do have a 200-4r (R4, which ever you like to say) sitting right next to me and I would be more than happy to take a pic of it to show the modulator valve.
Mechanics always seem to use the tranny for an excuse, but then can't explain HOW the smoke gets in the exhaust system. It just Looks like it does.

[Indian]

Id be lying if i said i knew how this would occur. A couple of years ago i went out and started my car and had a big cloud push out the back. It wouldnt engage into gear after only a little while after putting fluid in so i had it taken down to the tranny shop.
I guess he changed the modulator. He only charged me a couple of bucks if he wanted to rip me he could have ripped me at that time.

[jimfulco]

Many automatics (Turbo 350 & 400, etc.) have a vacuum modulator that has a rubber diaphragm in it. If the diaphragm breaks, rots, or whatever, engine vacuum will pull ATF through the broken diaphragm and into the intake manifold, causing smoke in the exhaust. T700R4's & 200-4R's don't have modulators, so they won't smoke like that.

[87442lover]

Originally posted by Indian
Id be lying if i said i knew how this would occur. A couple of years ago i went out and started my car and had a big cloud push out the back. It wouldnt engage into gear after only a little while after putting fluid in so i had it taken down to the tranny shop.
I guess he changed the modulator. He only charged me a couple of bucks if he wanted to rip me he could have ripped me at that time.

Well as I said I'm NOT mocking you or anyhting like that. I have seen tranny's blow out smoke(on the beltway a few times) when they go, or a bad shift, but it comes form the tranny, not the exhaust system.

As for the TH200's, they dont have a vacuum line to them, except for the 200-4r (4 speed version) that is longer, they do and I never thought of that. See I can be wrong

[Tina]

Thank you so much for responding to my transporter dilemma. I am so glad I joined hotrodders.com and for all your ideas. I have copied them and will once again get these things looked at and I will keep you posted. The new girl

[johnsongrass1]

Transport's are front wheel drive and are electronic shifted. Now I'm no automatic expert, Never even owned one in the last ten years I've been driving but the noise seems to be coming from the booster as well as it blowing fluid through the check valve. I seen this happen a few times on the transport's. I'm guessing you were complianing about a really touchy pedel, Mine was the same way.