Transmission making Hissing Noise

[85 Cutlass Brougham]

I have a Th200 4r transmission and it seems to be making a noise like a giant vacuum leak. It can be heard when in park or when in drive, and the volume varies with throttle application. I thought it was just a vacuum leak, but I could not find the noise under the hood, nor could I hear it under the hood when checking. It appears to be coming from under the car. As this transmission does not use a vacuum modulator, I have ruled it out as a possible culprit. Any suggestions are welcome, but I would prefer to not have to have it gone through as I have no money whatsoever to pay for it right now.

 

[pontiacgp]

are you sure it isn't coming from your exhaust?

 

[Bonnewagon]

Get a short piece of garden hose, hold it by your ear, and snoop around. You'll find it.

 

[monte olrac]

you could have a angry snake stuck somewhere...but if possible cap off all your vacuum lines and see if the noise goes away, i've heard brake booster make a hissing noise too.

 

[85 Cutlass Brougham]

are you sure it isn't coming from your exhaust?

I have wondered that too. I have a wasted and rattling catalytic converter and I have to wonder if the melted ball of what was the catalyst is plugging the outlet and causing backpressure to do it? It's almost like a whistling sound, maybe it is forcing air out a small leak between pipes in the front of the car? I dunno... I wish I had money to replace it so I didn't have to hear it, but I am in a VERY bad spot financially right now because I am forced to use the Cutlass to deliver pizza right now, and my whole financial world fell apart in the last 5 days.

 

[85 Cutlass Brougham]

Went underneath it today and had someone rev it, and it seems to be the catalytic converter. It has too much backpressure due to being melted, and is pushing the gases out the front of it. So, tomorrow morning I will try to deal with it the best I can before I go to work for a 12 hour shift.

 

[Blake442]

Just make a quick test-pipe to bypass the converter for now.
Since you don't have a welder (neither do I), here's how to improvise...

Use a pipe cutter or hack saw to remove the converter.
Get a chunk of scrap pipe that's the same length and diameter as the converter.
Go buy 2 cans of Spaghetti O's, four hose clamps, and a tube of muffler cement.

I say Spaghetti O's, because not many other canned food makers still use the old style cans that you can cut both ends off of.
Most now use the new stackable kind that don't allow it.

Eat and enjoy the Spaghetti O's, then wash out the cans and remove the labels.
Cut both ends off the cans, and use a tin-snips to make a cut down the can.
Fit your test pipe in place, and put a heavy bead of muffler cement around the ends of both the test pipe, and the remaining stock exhaust pipes.
Wrap the can around where they meet, and secure it with the hose clamps.
Run the car for a little bit, the heat will help cure the cement.

I have done this before, and I sh*t you not, it works... It's nothing to be proud of, but it'll get you by.

 

[85 Cutlass Brougham]

Thanks for the suggestion, but I kinda know what I plan on trying first. One end is flanged and held together with stainless steel nuts and bolts, so that side comes off easy. The other side is a slip fit and the cat is the outer pipe, and just barely will not come off. My plan is to slit the bottom of the outer pipe to give it enough extra space to come off. I will then pound the stuff out of it and put it back on, clamping it with a normal pipe clamp. The hole left before the clamp should be small and not leak enough to cause a lot of trouble. I am hoping that the car will not be needed for more than one more week as I think I can pay to fix the truck's transmission via some creative accounting. I really need to get it back because the rear suspension issues the Cutlass has make it impossible to drive it over 50 mph, and make it very unstable at speeds below that. Once the truck is stabilized, the Cutlass will be repaired to the point that it can see main service again without the problems that make it so hard to use right now (rear suspension, new gas tank, maybe a transmission, etc.). I figure I should be able to get a new car by late fall, but I need to stabilize both the cars I have now so that I can work until then.

 

[carmangary]

Spaghetti-O cans! LOL. I can't really laugh, though. I onced fixed a broken seat adjuster using a piece of a Cambell's soup can.

 

[Bonnewagon]

Wow, Blake, I thought only I used shade-tree fixes like that. Good show!