Transmission leak causes
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From: Sebastian,FL
Transmission leak causes
Have a 77 with auto trans, went to move it over the weekend and put in drive and no engagement, reverse as well. Looked under the car and see a decent puddle. Checked fluid and added some and it seemed to be fine. Are there any common spots that leak and are they changeable with trans in the car. Thanks
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Must be nice to live in Florida right now.
Can you roll it outside, hit it with degreaser, wash, and dry the transmission? Then roll it back, and place some cardboard under it?
The most likely cause of your grief is the lack of a clutch pedal. But the first spots to look for leaks are the speedometer cable and the transmission cooling lines. But once it's dry, hopefully something is obvious.
Can you roll it outside, hit it with degreaser, wash, and dry the transmission? Then roll it back, and place some cardboard under it?
The most likely cause of your grief is the lack of a clutch pedal. But the first spots to look for leaks are the speedometer cable and the transmission cooling lines. But once it's dry, hopefully something is obvious.
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Pan gasket is common. Change the filter too if that's it..
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From: New Or-leens Loo-z-anna
"The most likely cause of your grief is the lack of a clutch pedal."
You Guys!
As members said...give the trans a good bath....top off the fluid..remove trans dust cover....lay big piece of cardboard under the trans overnite...check cardboard for drips/puddles the next day.
IF there are no drips on the cardboard, start the car...warm up the engine...use E-Brake/block wheels from rolling...hold brake pedal down shift car thru gear range at 30 second intervals to give the trans time to drip in each gear/neutral/park/reverse/1-2-3
Put trans in PARK...look for fresh drips/puddles on cardboard and on fluid pan gasket/trans case/ on torque convertor seal/rear driveshaft seal/shift rod tiny seal/overflow tube at top of trans casegovernor cover seal//etc.
You Guys!
As members said...give the trans a good bath....top off the fluid..remove trans dust cover....lay big piece of cardboard under the trans overnite...check cardboard for drips/puddles the next day.
IF there are no drips on the cardboard, start the car...warm up the engine...use E-Brake/block wheels from rolling...hold brake pedal down shift car thru gear range at 30 second intervals to give the trans time to drip in each gear/neutral/park/reverse/1-2-3
Put trans in PARK...look for fresh drips/puddles on cardboard and on fluid pan gasket/trans case/ on torque convertor seal/rear driveshaft seal/shift rod tiny seal/overflow tube at top of trans casegovernor cover seal//etc.
Burning Brakes
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If it were me, I would definitely pump out the fluid before I removed (or loosened!) the pan, the mess trying to remove it full is appalling!😱 And that way you can get an idea how much has come out. I use a small hand pump when I do mine. Remember that there is a prescribed way to re fit the pan, a sequence of tightening etc, to ensure that the gasket does not leak in the future.
Before you do that, once you get the trans clean, you should see where the leak is coming from. I had an idea that the pan was leaking on mine, but once I cleaned it and was able to watch it over a day or so it was cleat that it was the shifter input shaft seal. That was a fairly easy fix and stopped the puddle forming! Another possible leak spot is the dipstick tube where it goes into the trans, and occasionally the vacuum modulator fittings. Right now I have a "weep" from the speedo drive, when the car has been standing for a couple of weeks. I've replaced the whole fitting gear etc, but it still weeps a bit. It's a real pain to change (the custom exhaust doesn't help!) and it's a tiny amount of fluid, so I confess it's staying as it is for a while!
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From: New Or-leens Loo-z-anna
I DO NOT recommend drilling, tapping, and putting a drain set screw in the torques converter.....
but I studied diagrams of internal Chevy torque converters and did it anyway,
Why drain only half of the old fluid and dilute it with new fluid, I asked
And No, the converter was not out of balance after the mod.
BUT...don't do it...unless you have PTSD.
but I studied diagrams of internal Chevy torque converters and did it anyway,
Why drain only half of the old fluid and dilute it with new fluid, I asked
And No, the converter was not out of balance after the mod.
BUT...don't do it...unless you have PTSD.
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Besides the front torque converter seal, my experience has been the dip stick tube "O" ring not seated, or the seal for the shift rod on the side of the tranny failing
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From: Sebastian,FL
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Here's the text of part of an article about changing the shifter seal:It seemed that fluid must have been escaping from a number of places as the pan and much of the bottom of the transmission was covered in fluid, and the underside of the car from the central cross-member back had a coating of “rust inhibitor”! I cleaned and dried as much as I could and after each run out in the car I examined the transmission. It soon became apparent that apart from anything else, there was fluid escaping from the shifter shaft seal on the driver’s side of the transmission. Initial enquiries implied that changing the seal with the transmission in situ was difficult and required a special tool, which appeared to be rather expensive and difficult to find. So I resigned myself to keeping the underneath of the car as free from transmission fluid as I could for some time.
Then by chance I read an article which mentioned changing the shifter shaft seal. Apparently, while care was needed, there was no need for special tools and it was a relatively easy fix. I had some seals sent over from the US (a spare or two just in case!) and rather pessimistically set aside a day for the work.
The shifter mechanism is located on the left (drivers side) of the transmission. The shifter cable attaches to a “quadrant” which is “indexed” to the shifter shaft by flats on the shaft. The shaft seal is pressed into the casing of the transmission and is exposed by releasing the shifter “quadrant”, which is held by just a single nut. The aforementioned special tool screws into the seal then tool and seal are removed. However, I had been told that it was possible to carefully prise out the seal with a small “pick”. I released the shifter cable from the quadrant, held by a split-pin, the nut from the shaft and carefully removed the quadrant. The seal is fairly deeply set in the casing, but I could see that I should be able to carefully prise the seal out. I confess that a small screwdriver was sacrificed before I found a more suitable tool! I now have a very nifty set of Draper “Mini Picks” which do the job admirably. Thanks Chris! It is important not to damage either the shaft or the seal housing during the removal of the seal. The new seal is simply pressed back into place, but great care must be taken not to damage the new seal on the sharp edges of the shaft “flats”. I wrapped the shaft in some plastic insulting tape, applied Vaseline to the shaft and seal and ensuring that the “dust cap” of the seal was outward, .gently “screwed” the seal down the shaft and seated it squarely in the housing. Then, using a suitably sized socket I gently tapped the seal down into the casing,.
Thankfully, it’s not necessary to drain the transmission beforehand. Because the shaft is a snug fit in the transmission casing only a tiny amount of fluid escapes while the seal is out, virtually no more than was leaking past the seal in fact!
The quadrant was located on the shaft and bolted back, the cable re-attached and the transmission given another thorough clean before we took a brief test run.
And this is the best part. Not only did the shifter seal not leak, but all that fluid going everywhere was apparently coming from that one tiny seal, as the ‘box was and has remained leak free!
For the work I supported the car on axle stands but in retrospect running the front of the car up on ramps would allow better access to the transmission. If you can use a pit or a lift, even better! Early cars may have a second cable attached to the quadrant related to the neutral/ignition lockout system. Take care not to disturb any cable adjustment bolts that may be present on the quadrant and of course use a new split pin when refitting the cable. The seal is AC Delco number 8657163 and is available from the usual UK Corvette parts suppliers, or can be bought for “pennies” from US stores like Pep Boys if you’re there! I took my time but accomplished the entire job in a couple of hours.
Then by chance I read an article which mentioned changing the shifter shaft seal. Apparently, while care was needed, there was no need for special tools and it was a relatively easy fix. I had some seals sent over from the US (a spare or two just in case!) and rather pessimistically set aside a day for the work.
The shifter mechanism is located on the left (drivers side) of the transmission. The shifter cable attaches to a “quadrant” which is “indexed” to the shifter shaft by flats on the shaft. The shaft seal is pressed into the casing of the transmission and is exposed by releasing the shifter “quadrant”, which is held by just a single nut. The aforementioned special tool screws into the seal then tool and seal are removed. However, I had been told that it was possible to carefully prise out the seal with a small “pick”. I released the shifter cable from the quadrant, held by a split-pin, the nut from the shaft and carefully removed the quadrant. The seal is fairly deeply set in the casing, but I could see that I should be able to carefully prise the seal out. I confess that a small screwdriver was sacrificed before I found a more suitable tool! I now have a very nifty set of Draper “Mini Picks” which do the job admirably. Thanks Chris! It is important not to damage either the shaft or the seal housing during the removal of the seal. The new seal is simply pressed back into place, but great care must be taken not to damage the new seal on the sharp edges of the shaft “flats”. I wrapped the shaft in some plastic insulting tape, applied Vaseline to the shaft and seal and ensuring that the “dust cap” of the seal was outward, .gently “screwed” the seal down the shaft and seated it squarely in the housing. Then, using a suitably sized socket I gently tapped the seal down into the casing,.
Thankfully, it’s not necessary to drain the transmission beforehand. Because the shaft is a snug fit in the transmission casing only a tiny amount of fluid escapes while the seal is out, virtually no more than was leaking past the seal in fact!
The quadrant was located on the shaft and bolted back, the cable re-attached and the transmission given another thorough clean before we took a brief test run.
And this is the best part. Not only did the shifter seal not leak, but all that fluid going everywhere was apparently coming from that one tiny seal, as the ‘box was and has remained leak free!
For the work I supported the car on axle stands but in retrospect running the front of the car up on ramps would allow better access to the transmission. If you can use a pit or a lift, even better! Early cars may have a second cable attached to the quadrant related to the neutral/ignition lockout system. Take care not to disturb any cable adjustment bolts that may be present on the quadrant and of course use a new split pin when refitting the cable. The seal is AC Delco number 8657163 and is available from the usual UK Corvette parts suppliers, or can be bought for “pennies” from US stores like Pep Boys if you’re there! I took my time but accomplished the entire job in a couple of hours.
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Pro
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From: Sebastian,FL
Ok so got to the weekend and had a chance to clean it up, I don’t see any drips after it sitting a while. Went thru all gears and engaged as should. i dont see any glaring drips but im thinking I’ll change the filter and gasket as the gasket appears to be cork and it looks saturated at the edges.
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I'd stick with cork. My last filter came with a rubber gasket that leaked like a sieve....had to drop the pan & change it..
