Leaky transmission - What can I do?
02-26-2015, 03:22 PM
#1
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Leaky transmission - What can I do?
I have an 89 car with an 88 trani in it
Every 928 I've own seeps at the trani area. (3 cars now) It's a problem because if you don't check it and add more fluid every few months, the trani can burn up from being low on fluid.
I did remove the reservoir tank and replace the o-ring there, yet it seem to still be dripping every few days. Where else should I check? What are the common areas address?
Every 928 I've own seeps at the trani area. (3 cars now) It's a problem because if you don't check it and add more fluid every few months, the trani can burn up from being low on fluid.
I did remove the reservoir tank and replace the o-ring there, yet it seem to still be dripping every few days. Where else should I check? What are the common areas address?
02-26-2015, 03:24 PM
#2
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Torque converter seals are a good one too.
WHERE does it drip from?
When I bought my 88 years ago, it was a river of leaks, quart a day. Every "fill" was stop leak, and it stopped after a few weeks..until I could get a proper R&R, but it was TC seals for me.
WHERE does it drip from?
When I bought my 88 years ago, it was a river of leaks, quart a day. Every "fill" was stop leak, and it stopped after a few weeks..until I could get a proper R&R, but it was TC seals for me.
02-26-2015, 03:29 PM
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Torque converter seals are a good one too.
WHERE does it drip from?
When I bought my 88 years ago, it was a river of leaks, quart a day. Every "fill" was stop leak, and it stopped after a few weeks..until I could get a proper R&R, but it was TC seals for me.
WHERE does it drip from?
When I bought my 88 years ago, it was a river of leaks, quart a day. Every "fill" was stop leak, and it stopped after a few weeks..until I could get a proper R&R, but it was TC seals for me.
02-26-2015, 03:34 PM
#7
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There is the TC seal, but also the oil pump seals fail- there is an o-ring that gets brittle and smashed over time. Other seals in this areas well, but that one is common.
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02-26-2015, 03:37 PM
#8
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People (including me) take the transmissions out and reseal the front pump assembly. The "O-ring" that seals the cast iron pump into the aluminum housing gets hard as a rock and leaks.
The "problem" with that fix is that all of the other internal O-rings are also hard as rocks and leaking the same amount....you just can't see them leak.
I generally encourage people to rebuild the entire transmission, once it is out and you are chasing that leak. We were just discussing this on another thread. The "beauty" of rebuilding these units before they completely wear out and damage the "hard parts" is that the cost of rebuilding is reasonable.
One of the absolute worst "value for what you receive" are the "flat price" automatic transmission rebuilders. Getting something rebuilt for a "fixed price" is like asking the rebuilder to put as few pieces as possible into something, to maximize the profit.
These transmissions are tough. You could virtually put $400 worth of parts into each and every one of these things and make it not leak and work for 20,000 miles. The pieces needed to make them last another 150,000 miles are way, way different!
The "problem" with that fix is that all of the other internal O-rings are also hard as rocks and leaking the same amount....you just can't see them leak.
I generally encourage people to rebuild the entire transmission, once it is out and you are chasing that leak. We were just discussing this on another thread. The "beauty" of rebuilding these units before they completely wear out and damage the "hard parts" is that the cost of rebuilding is reasonable.
One of the absolute worst "value for what you receive" are the "flat price" automatic transmission rebuilders. Getting something rebuilt for a "fixed price" is like asking the rebuilder to put as few pieces as possible into something, to maximize the profit.
These transmissions are tough. You could virtually put $400 worth of parts into each and every one of these things and make it not leak and work for 20,000 miles. The pieces needed to make them last another 150,000 miles are way, way different!
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greg brown
714 879 9072
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Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
greg brown
714 879 9072
GregBBRD@aol.com
Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
02-26-2015, 04:01 PM
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People (including me) take the transmissions out and reseal the front pump assembly. The "O-ring" that seals the cast iron pump into the aluminum housing gets hard as a rock and leaks.
The "problem" with that fix is that all of the other internal O-rings are also hard as rocks and leaking the same amount....you just can't see them leak.
I generally encourage people to rebuild the entire transmission, once it is out and you are chasing that leak. We were just discussing this on another thread. The "beauty" of rebuilding these units before they completely wear out and damage the "hard parts" is that the cost of rebuilding is reasonable.
One of the absolute worst "value for what you receive" are the "flat price" automatic transmission rebuilders. Getting something rebuilt for a "fixed price" is like asking the rebuilder to put as few pieces as possible into something, to maximize the profit.
These transmissions are tough. You could virtually put $400 worth of parts into each and every one of these things and make it not leak and work for 20,000 miles. The pieces needed to make them last another 150,000 miles are way, way different!
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greg brown
The "problem" with that fix is that all of the other internal O-rings are also hard as rocks and leaking the same amount....you just can't see them leak.
I generally encourage people to rebuild the entire transmission, once it is out and you are chasing that leak. We were just discussing this on another thread. The "beauty" of rebuilding these units before they completely wear out and damage the "hard parts" is that the cost of rebuilding is reasonable.
One of the absolute worst "value for what you receive" are the "flat price" automatic transmission rebuilders. Getting something rebuilt for a "fixed price" is like asking the rebuilder to put as few pieces as possible into something, to maximize the profit.
These transmissions are tough. You could virtually put $400 worth of parts into each and every one of these things and make it not leak and work for 20,000 miles. The pieces needed to make them last another 150,000 miles are way, way different!
__________________
greg brown
02-26-2015, 08:24 PM
#11
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When I bought my 88 S4 automatic last year, it was leaking transmission fluid. It ended up being the rubber vent hose that runs from the top of the plastic reservoir to the transmission case. It's hard to see and a little bit of a pain to replace, at least for my fat hands, but was an easy fix. Now, it's nice and dry.
02-27-2015, 05:58 AM
#12
Rennlist Member
I recently repaired reverse on my GTS automatic. Translated my post from the german forum for you guys. Took a couple of pictures. This should help to get you an idea where the leak could come from... https://rennlist.com/forums/928-foru...ement-diy.html
If you go to youtube look up a "mercedessource" he has very good tutorials on the typical leaks of 722.3 transmissions.
If you go to youtube look up a "mercedessource" he has very good tutorials on the typical leaks of 722.3 transmissions.
02-27-2015, 06:54 PM
#13
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thought my TC seal was leaking so recently had all the external seals replaced, including the pump seals (the culprit).
it was a quarter-sized drip 15 years ago, lately it was about the size of a baking sheet.
enough is enough.
it was a quarter-sized drip 15 years ago, lately it was about the size of a baking sheet.
enough is enough.
03-02-2015, 04:47 PM
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How does being closer to LA help?
It'll take him a few weeks to do it right.
It's not a weekend thing.
It'll take him a few weeks to do it right.
It's not a weekend thing.
The oil is dripping every few days from the reservoir area. I'll take a closer look at the cap, hose and ban gasket.