Viscous clutch
 

Please Help. Now My car has been shuddering on the right front under mild acceleration, mainly from a dead stop. I replaced the right front axle and when I did, fluid drained out from the viscous clutch. Do I need to add fluid to the clutch or does is get from the transmission? The shuddering was there before I changed the axle but not quite as bad.

99 S80 T6

Hi Bill,

I see that you didn't get any response. How did you sort this out?

I'm about to try and replace the viscous clutch seal and I'm also wondering how the gearbox oil is supplied to the viscous clutch.

Thanks,
Oscar

What is this mysterious "viscous clutch" that you think is part of a 99 s80 2wd Volvo? (what you probably have is a bad/slipping transmission)

1998 to 2002 AWD Volvos have a viscous clutch - that when the front wheels turn faster than the rears - the clutch fluid heats up and sorta engages Rwd

oscarvolvo, you commented on a 12 year old thread so its likely the OP is no longer active. Post up your year and model and which seal you are looking to replace. As noted, FWDs only have a transmission to service. AWDs have three components - the transmission (which takes the appropriate fluid type such as Dex III or JWS3309), the bevel gear (aka angle gear) which takes GL5 gear oil) and some have a haldex coupler which takes its own fluid type specific to the model. Volvo friendly web stores like IPD, FCP and dealers sell haldex service kits which include seals, filters, fluid etc specific to your year/model.

The car is a Volvo S80 T6 '99 2WD. It is one of the few ones from the years 99 and 00 that has a viscous clutch. There is no problem with the car (no shudder nor slip) except that it leaks a bit of transmission fluid. I plan to replace the seal marked with #2 in the attached picture. I believe it is Volvo part # 8636206. What I'm not sure about is how to separate the viscous clutch (the black thing in the picture) from the driveshaft. Moreover it is not clear to me how it is lubricated. It leaks transmission fluid so my guess would be that it is supplied with ATF from the transmission via the driveshaft somehow.

Anyone with experience of such a job?





https://cimg3.ibsrv.net/gimg/volvofo...615a1d4730.jpg

If you google Volvo Visco Clutch" you'll see some threads on Matthews and other boards. see https://www.matthewsvolvosite.com/fo...ic.php?t=94508

It looks like its a self contained unit (with an expensive replacement cost :-( You can Google Part Number: 9480805, Supersession(s): 9181543 ) on a dealer store to see what the replacment axle looks like.

Have you been able to remove the axle to do the seals yet?

I've seen articles that talk to silicone fluid being used in viscous couplers so I don't think its standard ATF. https://www.s1built.com/ sells viscous axles that use 60k cst fluid so they may be worth calling and see if they offer a rebuild service.

Post up how you make out.

Never done one but it looks like it's simply splined onto the axle. Here's how Volvo says to replace that seal.
https://cimg5.ibsrv.net/gimg/volvofo...85984bdec6.jpg
https://cimg6.ibsrv.net/gimg/volvofo...f56a1a5f92.jpg
https://cimg8.ibsrv.net/gimg/volvofo...4029817a5d.jpg

Thanks a lot for your help guys. I learned that the driveshaft can be tapped out from the visocous coupling in the link that you posted to the other forum. Thanks also for the good instruction on how to replace the seal. I will attempt it without the special tool referenced in the instruction. I think I will wait until the spring to do this job as I don't have a garage to work in. The leak is minor so I can manage until then by topping up the transmission fluid. I will update you once I have a go at this.

So I finally had a go at this job. Some notes that may help others:
The Volvo dealer (at least in Sweden) couldn't say which of the two sealing rings was the right one for my car. They blamed their data system and that it only goes back to the year 2000 and my car is a 1999. In my case the early 42 mm version (part 8636206) was the correct part. I suspect that they quite early changed the design because it was inherently bad and typically leaked. Unfortunately this older part is no longer supplied by Volvo. Luckily I was able to source an original part from a third party.

The removal and replacement went well thanks to you guys and hoonk's excellent instruction in particular. The vicous clutch is just held with a retaining ring and can easily be separated from the drive shaft by tapping it out (small amount of force needed). The seal itself was a bit of a pain to get out but could be done according to hoonk's guide (careful not to pry against the needle bearings and damage them). I did not have the Volvo seal installation tool but I found that a 30 mm socket was a perfect fit to tap in the new seal.

A picture of the viscous clutch with the original seal:

https://cimg1.ibsrv.net/gimg/volvofo...f70cf845cf.jpg
Viscous clutch with original seal (42 mm)

I have now driven some 1000 km since the seal replacement. No more oil leaks. Thanks Volvo forums!