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Transmission refresh- which seals?

 
Old 01-22-2019, 03:36 PM
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SRaouf
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Default Transmission refresh- which seals?

As part of my restoration project Ive removed the TT and transmission and replaced the TT bearings (with super bearings & clamp). I'm following dwayne's guide and will be replacing the TC bearings as well, but does anyone have a list of the seals I should replace while I have the transmission out? I assume the front seal is a given, but are there any others that are prone to leak but can be replaced relatively easily? I would really rather not mess with the innards/bands if I can avoid it. One seal often mentioned is the front pump O ring. How easy is it to replace? this guide has some grate pics but does show the pump and rear piston (?) being removed http://jenniskens.livedsl.nl/Technic...8/MyTip876.htm

The car previously lay dormant for 15 years so Im not sure if the transmission leaks although I did manage to get it started and a gears seemed to work before I took it apart.

Sam 85 S2 Auto 100K miles
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Old 01-22-2019, 08:16 PM
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By the time you pull the pump out of the case you might as well also replace the B3 piston (likely damaged from the hard engagement inherent in the valve body design. See Greg Brown's posts), B3 clutches/steels, B3 piston seals, and B3 retainer and springs. This will prevent you losing reverse gear sometime in the future and having to drop the trans again to address it.
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Old 01-22-2019, 09:42 PM
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Originally Posted by SRaouf View Post
As part of my restoration project Ive removed the TT and transmission and replaced the TT bearings (with super bearings & clamp). I'm following dwayne's guide and will be replacing the TC bearings as well, but does anyone have a list of the seals I should replace while I have the transmission out? I assume the front seal is a given, but are there any others that are prone to leak but can be replaced relatively easily? I would really rather not mess with the innards/bands if I can avoid it. One seal often mentioned is the front pump O ring. How easy is it to replace? this guide has some grate pics but does show the pump and rear piston (?) being removed http://jenniskens.livedsl.nl/Technic...8/MyTip876.htm

The car previously lay dormant for 15 years so Im not sure if the transmission leaks although I did manage to get it started and a gears seemed to work before I took it apart.

Sam 85 S2 Auto 100K miles
Just taking the transmission in and out, you will want to replace the kickdown O-ring: 999 701 664 40
If the bellows for the shift cable is deteriorated (it will be) replace it, before the cable gets water inside and won't move: 922 424 103 00

The most common leak is from the front pump O-ring, which is fairly straight forward to fix. You will need to remove the front pump assembly from the front of the transmission, remove the B3 piston, and remove the pump assembly. I also always replace the torque converter seal. You will need:

1-016 997 14 48 Pump O-ring
1-126 271 12 80 Pump body gasket (although some people re-use this gasket, with some sealant on it....they are very time consuming to scrape off. (I never leave the old gasket in place....not my style.)
1-126 272 01 92 B3 outer piston seal
1-126 272 00 92 B3 inner piston seal
1-018 997 04 47 Converter seal

I generally also replace the two teflon seals that the B1 clutch rides on (these are located on the front pump assembly.)
2-126 272 09 55 Teflon Seals.

The most common mistake, with has ruined a bunch of people's days/weeks is to not lubricate the bushing for the torque converter (behind the torque converter seal.) Lubricate this bushing with Vasoline or transmission assembly lube.

Getting any further into the transmission (to replace the B3 reverse clutches, which are the first clutches to wear out on 99.9% of these transmissions) requires a bit more knowledge.....if you feel brave, you will need:
4- 126 272 09 25 Clutch plates

We stock and sell all of these pieces, if you decide to do this and need to order the parts.
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Old 01-23-2019, 05:13 AM
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Thank you. This is very helpful. Once I replace the TC bearings I'll see if I can get the pump out without making too much of a mess before I decide whether to risk doing the B3 clutches.
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Old 01-24-2019, 10:51 AM
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SRaouf, do it! I have just (well, reasonably recently) done all this. None of it is super difficult. There are threads on Rennlist that can help walk you through it, and the service manual is invaluable.
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Old 01-25-2019, 05:00 PM
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It's a slippery slope.

The one thing that you always need to keep in mind, as you take the front pump apart and chisel out the old O-ring, is that every O-ring and seal inside the transmission is now exactly as hard as that O-ring.

Thirty five year old rubber parts, which have been heated and cooled 10,000 times, have long passed their life expectancy.
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Old 04-14-2019, 01:41 PM
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Originally Posted by SRaouf View Post
As part of my restoration project Ive removed the TT and transmission and replaced the TT bearings (with super bearings & clamp). I'm following dwayne's guide and will be replacing the TC bearings as well, but does anyone have a list of the seals I should replace while I have the transmission out? I assume the front seal is a given, but are there any others that are prone to leak but can be replaced relatively easily? I would really rather not mess with the innards/bands if I can avoid it. One seal often mentioned is the front pump O ring. How easy is it to replace? this guide has some grate pics but does show the pump and rear piston (?) being removed http://jenniskens.livedsl.nl/Technic...8/MyTip876.htm

The car previously lay dormant for 15 years so Im not sure if the transmission leaks although I did manage to get it started and a gears seemed to work before I took it apart.

Sam 85 S2 Auto 100K miles
Hey SRaouf - looks like I am ~2m behind you doing exactly the same things to my 85 S2! Having done "everything at the front", "everything at the back" seemed like the obvious next step. Just about to jump into transmission world once it is cleaned up so it's really great you posted this thread and the link.
David
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Old 04-14-2019, 03:40 PM
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SRaouf
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Quite a learning experience! In the end I replaced most of the items mentioned by Greg above

1-016 997 14 48 Pump O-ring
1-126 272 01 92 B3 outer piston seal
1-126 272 00 92 B3 inner piston seal
1-018 997 04 47 Converter seal
2-126 272 09 55 Teflon Seals.
I left the thin pump body gasket on as it looked in good condition, wouldn't come off easily and I was worried I might damage the mating surfaces. I didn't go any further into the box as I found that it was a replacement transmission and the seals I took out were still soft.

I also replaced the kick down o ring and rebuilt the shifter cable as the hollow tube towards the transmission snapped off because of rust (I used a double nut and tapped a new tube into it). The vacuum modulator wasn't holding any vacuum so I replaced it with the newer green one. Finally I also replaced the K1 spring to reduce 2nd to 3rd flare as it was easy and cheap while I had the box out

Hope that gives you some pointers. it was all quite straightforward but one thing to really watch out for is when you fit the TC back on to the primary pump make sure it is seated proparly as the pump gear has two inner teeth that will snap off. I learned this the hard way and the replacement part wasn't cheap!





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