TheSamba.com :: View topic - Oil Slinger-What It Is, What Can Happen, and How To Fix It.

Fri Feb 13, 2009 6:34 pm

A "soapbox" I've been preaching from for a while now is "always check the oil slinger before installing a tranny". After coming across another premature failure, this one less than 18 months after a very prominent, and expensive shop "fixed" the whole clutch system (after a seemingly catastrophic failure), I feel like perhaps a pictorial would be helpful. It is a seemingly inconsequential part and yet can cause an incredible amount of expense in both labor and materials and often does.

The awl in the following picture is pointing to the slinger:

The input shaft oil slinger is a metal sleeve that resides behind the input shaft seal in the transmission. It has a spiral flute or thread on it's inner surface. It should be a press fit into the bell housing. It's purpose is to "sling" tranny fluid away from the input shaft seal and extend it's life. It does so in the following manner. The input shaft, while spinning, gets the tranny fluid to spin around it. The flute of the slinger is oriented so that with the clockwise rotation of engine and input shaft, the spinning motion of the tranny fluid, forces the fluid away from the seal. Quite ingenious really.

What goes wrong is that on occasion the slinger becomes loosened from it's press fit in the bell housing. This is most often caused by a failure of the pilot bearing in the end of the crankshaft. The failure of the pilot bearing allows the input shaft to flop around excessively. In turn, the flopping input shaft hits the slinger and in short order frees it from it's press fit. As an aside, I feel the premature failure of pilot bearings is quite frequently caused by the removal of the felt ring in the flywheel which prevents the clutch dust from ruining the pilot bearing rollers. Although, the pilot bearing might be fine, I always check the slinger as the last mechanic to install the pilot bearing might not have.

Once the slinger is no longer a press fit in the bell housing, it is no longer a help, but rather a cause of destruction. The flute of the slinger is oriented such that once it is no longer held in the bell housing, the tranny fluid, instead of being slug away from the seal, now actually spins the slinger and throws it AT the seal, chewing up the back of it. Once the input shaft seal is sufficiently chewed, it will leak tranny lube, often significantly. I have actually seen where it got on the clutch and actually caused (coupled with stupid driving techniques) the explosion of the clutch disc.

I ALWAYS CHECK THE SLINGER IN THE BELL HOUSING PRIOR TO INSTALLING A TRANSMISSION!! YOU SHOULD TOO!!

That's worth repeating.

I ALWAYS CHECK THE SLINGER IN THE BELL HOUSING PRIOR TO INSTALLING A TRANSMISSION!! YOU SHOULD TOO!!

The check is simple. Remove the input shaft seal (a seal puller or sheet metal screws and a couple pry bars are good methods, IMO) and use a small pic or eyeglasses screwdriver to pry on the slinger. If it moves, IT MUST BE ADDRESSED to avoid significant costs in parts and labor in the very near future.

To address the failure, I remove the bell housing from the transmission (6 bolts in the clutch housing area and 4 below m8 - 13mm heads), I remove the slinger, peen the surface that should hold it so that the press fit is restored, clean the various surfaces with brake cleaner and JBWeld it in place. I feel that the combination of the JBWeld and peens is a permanent fix.

Here is the surface that needs to be peened:

Use a punch to make dimples. Although the dimples depress the metal further, the edges of the dimples cause the metal to raise and will grip the slinger.

Here is a picture of the surface after being peened:

After I'm convinced the press fit is restored, I mix up some JBWeld, slather it on the peened surface and the face that is in the direction of the flywheel and hammer in the slinger. Once the gasket surface is cleaned thoroughly and the JBWeld has set up, then the bell housing can be installed on the transmission. I use a very thin coating of Permatex on both the tranny and bell housing mating surfaces and torque them together.

Here's one shot on the tranny side:

And here's one on the clutch side:

I would add that this is a VERY COMMON failure. Probably half of the transmissions I've removed have had a flopping slinger accompanied with a leaky input shaft seal.

Once more just for good measure:

I ALWAYS CHECK THE SLINGER IN THE BELL HOUSING PRIOR TO INSTALLING A TRANSMISSION!! YOU SHOULD TOO!!

Andrew

Fri Feb 13, 2009 6:41 pm

sticky time =D>

Sat Feb 14, 2009 7:39 am

Wow! Very nice! Thank you Andrew. This one will go in my Bookmark's next to the Libby Bong.

Tue Feb 24, 2009 2:18 pm

fantastic writeup, thank you for this!

Tue Feb 24, 2009 3:14 pm

Great example of an "unseen" part that could be overlooked. Possibly something typically not looked at in spite of the fact that these are aging vehicle some with high km's.

i.e. One of my first forays into Vanagon wrenching was to rebuild the clutch housing. Did everything. Bushings, tube, arm, but, uh, didn't know to check that slinger. :roll: But then I'm just a muso with a few wrenches ;)

Very thoughtful of you to post the text/pics.

Thanks!

Neil.

Fri Mar 12, 2010 1:46 pm

I just pulled my trans to replace a bad pilot bearing, and discovered several tablespoons worth of hypoid in the bottom of the clutch case. Looks like at least a bad input shaft seal and after reading this thread maybe a slinger too.

I did notice about 1/8th of an inch of side to side play in the shaft.

Any help finding a vendor that sells just the output shaft seal. Gowesty has it as part of the whole transmission gasket set for just under $50, and napa sells one that looks substantially less meaty for $8. Id like to get a better one than the napa version but I don't want to pay for all the gaskets.

Fri Mar 12, 2010 2:21 pm

These seals are readily available from virtually any place that specializes in VW parts. Don't know what NAPA sells, never thought of buying that seal from them.

Remember to ask for the input shaft seal and not the output shaft seal as you mention in your post. Some movement of the input shaft is normal.

Fri Mar 12, 2010 3:55 pm

It is normal to see that amount of play in the input shaft. The tip of it is held by the pilot bearing in the crank, so once installed it is stabilized.

www.autohausaz.com has a much better seal than the NAPA version and for 1/3rd the price...

http://www.autohausaz.com/search/product.aspx?sid=...Oil%20Seal

Fri Mar 12, 2010 4:39 pm

Andrew A. Libby wrote: It is normal to see that amount of play in the input shaft. The tip of it is held by the pilot bearing in the crank, so once installed it is stabilized.

www.autohausaz.com has a much better seal than the NAPA version and for 1/3rd the price...

http://www.autohausaz.com/search/product.aspx?sid=...Oil%20Seal

Boy, I opened the page you linked to and saw the list price and almost choked, then saw the actual price and could breath again.

$2.35 actual verses $23.83 list.

!!!Sigh!!!

Fri Mar 12, 2010 6:25 pm

What an incredibly timely post to stumble across. I'm in the middle of removing my transmission to look for a massive leak in the bell housing!

Thanks for the awesome write-up!

Tue Mar 16, 2010 2:48 pm

OK, so I got my bellhousing off and the oil slinger was loose!

Man, what a life-saver this thread is! Without it I might have just replaced the main seal & re-installed everything...

So I have a question. On the inside of the slinger is the spiral groove, and it's a little worn out where it was pressed against the input shaft. The high points on either side of the groove are worn down just barely to the groove's level, for about a centimeter of arc, way out on the outer end of the slinger. Like about a half-turn of the spiral would bring you to the end of the slinger.

Can I re-use this slinger, or is it toast?

Tue Mar 16, 2010 4:12 pm

That's a judgment call. I would at least use a dremel tool to re-create the spiral if there is enough meat left. I don't think you'll find the slinger outside of the whole bell-housing so the other option is replacing the bell-housing.

Tue Mar 16, 2010 4:22 pm

Thanks, I was leaning in that direction.
Actually, at this point I am leaning very strongly in the direction of putting the camper bits on the carat and parting out the damned-by-every-religion's-god(s) syncro, but that's a rant for another day.

Wed Mar 17, 2010 10:47 am

Just another "thanks". Am in the middle of swapping trannys and input shafts, (I use a shorter shaft for Jetta engine) so have a chance to check the slinger etc. Wouln't have done this were it for your post.

Andrew. Do you know if there's a felt seal for a "Vanagon" KEP flywheel?

I didn't install one but did install a slightly longer pilot bearing. I understood it to be a "sealed" item.

Maybe use a WBX felt seal?

Much appreciated,

Neil.

Wed Mar 17, 2010 12:12 pm

I would just use the diesel pilot bearing which has the rubber seal and forget the felt ring. Be sure to orient the pilot bearing with the seal to the exterior of the crank.

Andrew

Wed Mar 17, 2010 7:08 pm

Andrew A. Libby wrote: I would just use the diesel pilot bearing ....
Andrew

Thanks Andrew. Good idea. Just got the tranny/input shaft out and all looks good though there is a very faint ring near end of input shaft. Didn't feel any difference in OD so should be ok. I figure ring appeared because this portion of shaft was "new" (shortened the shaft) and just normal wear/tear.

That's the theory anyway. ;)

I'll do the PB changeover when the clutch is due.

Thu Mar 18, 2010 11:00 am

So to be clear...

Can the slinger be checked for play with input shaft seal installed?

Cheap part, but input shaft seal appears to be fine.

Thanks,

Neil.

Thu Mar 18, 2010 11:09 am

I don't think it can be checked without pulling the seal. Then with a very small screwdriver or awl you can try to move the slinger.

Thu Mar 18, 2010 11:16 am

Thanks for the speedy reply Andrew.

Was just heading out for parts. They have a DV PB too. I'll be curious about the price. (not dealership) ;)

Neil.

Wed Jun 16, 2010 7:07 pm

Hey Andrew,

This thread is right on. When replacing my pilot bearing I checked the slinger and just as you said it was loose as a goose. You said you apply permatex to the surfaces of both the transmission and the cover when reassembling. Does that allow you to not use a gasket. I cant seem to find one without buying the whole set and don't want to lay out $50 for one gasket. The one that was on there came out in one piece so I guess I could cut a new one if needed. Also the end of my input shaft has some wear form the bad pilot bearing. I can feel a groove there. Is that going to trash teh new pilot bearing?

Thanks
Max