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Old 05-11-2020, 03:31 PM   #1
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Input and Output Shaft Seals -- grease or not?

My input shaft seal was leaking on my 99 Box 5 spd trans so I'm replacing the input shaft seal and o-ring. As long as the trans is out, figured I'd replace the output shaft seals as well since they're 21 years old.

Question: When installing the new shafts do they go in dry or do you lubricate the inside shaft seal with trans fluid or grease? If grease is recommended, what type?

Assuming "dry" since I searched the forum and the 101 projects book didn't specify as far as I could tell...

However, appreciate the input from experts here. Pls advise.

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Old 05-11-2020, 03:48 PM   #2
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You need to lubricate the sealing surface with clean oil after installing the seals and before you push the shafts in..
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Old 05-12-2020, 06:59 AM   #3
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See #17 from the manual.


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Old 05-12-2020, 08:14 AM   #4
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I'm guessing as you say "shafts" you are talking about the splined shaft that passes through the hub and the axle nut torques onto? Based on my experience that every axle I've removed had it (4 cars and counting) this should be lightly coated with a COPPER anti-seize.
all the seals and rings are lightly oiled when replacing and voids are filled with bearing grease.
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Old 05-12-2020, 02:11 PM   #5
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Tony, I believe that he was referring to the shaft that goes through a seal, like the driveshafts into the sides of the transaxle or the input drive shaft.
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Old 05-12-2020, 02:32 PM   #6
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Thanks for the feedback. tonythetiger: I think you're referring to the drive shafts at the wheel hub?

I'm referring to the input shaft seal which surrounds the transmission input shaft (that connects to the engine flywheel) and keeps the transmission fluid from leaking out of the shaft bearings into the bell housing -- which is what I think mine was doing. Here's a pic of it:https://cdn4.pelicanparts.com/techarticles/Boxster_Tech/44-TRANS-Clutch/images_med/Pic05.jpg

....and here is a photo of the output shaft seals. These are the seals that surround the splined drive shafts on either side of the transmission: https://cdn4.pelicanparts.com/techarticles/Boxster_Tech/39-TRANS-LSD/images_med/Pic03.jpg

Based on what 911monty shared, it sounds like the inside of the hollow seal should be filled with grease(bearing?). Doesn't mention the inside surface which seals the shaft and sits on the shaft surface that is spinning. Gilles recommends clean (trans) oil on this surface which makes sense to me but the manual shared by 911monty doesn't mention it.
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Old 05-12-2020, 03:28 PM   #7
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Quote:
Originally Posted by geekdaddy View Post

Based on what 911monty shared, it sounds like the inside of the hollow seal should be filled with grease(bearing?). Doesn't mention the inside surface which seals the shaft and sits on the shaft surface that is spinning. Gilles recommends clean (trans) oil on this surface which makes sense to me but the manual shared by 911monty doesn't mention it.
I thought that was pretty clear, but let's try this. The output shaft seal is driven into the transaxle housing dry 5.5 mm below the surface. The 2 lips of the seal that contact the output flange shaft get grease in the small void between the inner(seal) and the outer (dust) lips that are in contact with the axle hub shaft. This provides lubrication as the hub is driven into the transaxle and I believe creates a dam that helps prevent the abrasive clutch friction disk dust from getting to the inner seal lip. I lightly coated the hub shaft with gear oil before driving it on the output shaft.
The input shaft seal (towards the flywheel) gets greased the same (that's the same as 17 remark). On the diagram 17 is the input shaft seal and 25 is the output shaft seal.
Hopefully this will clear up the confusion.

Last edited by 911monty; 05-12-2020 at 03:49 PM.
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Old 05-12-2020, 04:24 PM   #8
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so, now I understand you are referring to the transmission main seal that sits behind the release bearing guide tube. Gotcha. It looks like these have dust shields and the sealing surface.
I have 3.2L 6 speeds, so the setup there is a little different. I have a single seal (no dust shield) that sits back on the shaft 5mm or so. I oil the shaft and drop it in and replace the tube.
carry on.
:+)
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Old 05-13-2020, 09:09 AM   #9
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OK -- NOW I get it -- thanks for clarifying!

Quote:
Originally Posted by tonythetiger View Post
so, now I understand you are referring to the transmission main seal that sits behind the release bearing guide tube. Gotcha. It looks like these have dust shields and the sealing surface.
I have 3.2L 6 speeds, so the setup there is a little different. I have a single seal (no dust shield) that sits back on the shaft 5mm or so. I oil the shaft and drop it in and replace the tube.
carry on.
:+)

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