Syncro stripped viscous coupler splines

tim_ha · Last edited by tim_ha on Tue Oct 08, 2013 8:02 am; edited 1 time in total

Today, while I had both of my rear axles out for some CV maintenance, I decided it would be a good chance to test my viscous coupler.

reeee reeee reeee (horror movie sound effect)...

I gently let the clutch out and get
grrrrrrrrrrrrrrrrrrrrr (roll the rrrrr as in Spanish) Mad

I was planning on pulling the front axles and doing the front CV maintenance, but I guess that I will be rebuilding the front differential too.

I bought this van just over a year ago, am essentially the second owner but got no maintenance history from the original owner. This is the first time I have done a controlled test of the viscous coupler Embarassed

and now have some questions for all of the experts out there.

First off, does anyone have any diagnoses from my very limited knowledge/description of the problem at this stage?

Recommendations for doing the rebuild, sourcing parts, etc?

What else should I do while I am doing this? Seals to replace, upgrades to perform, check front wheel bearings, etc?

I have used the google driven samba search as well as looked in FAQs, but didn't find much on front diff rebuild.

Thanks for the help!
_________________
1986 Syncro Sunroof EJ22
www.subagonsouth.com

kbeefy · Posted: Tue Oct 01, 2013 10:39 pm Post subject:

I think you can rebuild/replace the VC without a full front end teardown.

Any further front end diagnosis? Jack one wheel up and turn it w/ van in and out of gear?
_________________
86 syncro CHC, NorthWesty subbie 2.5, decoupler, locker, custom interior, 225/75r16 Duratrack's on CLK's, Toyo cabin heater, ARB fridge, 300w Zamp Solar, Gowesty bumpers/skid/rails, Fiama awning

'86 Syncro Westy. Stock for now.

2000 F350 7.3 CC LB 11' Northland Cabover

2006 Subbie OBXT

2002 Tacoma DoubleCab 4x4

1969 Mustang Basket Case 351c/FMX/9

http://kbeefy.blogspot.com/

IdahoDoug · Posted: Wed Oct 02, 2013 12:02 am Post subject:

If you want to refill your VC, I have the fluid available for sale in the amount for a VC. I also have one seal kit, which you will need and will be selling the kit and fluid as a package. After that, I will have just the fluid for sale.

PM me.

DougM
_________________
1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader

tim_ha · Posted: Wed Oct 02, 2013 8:04 am Post subject:

Thanks, IdahoDoug, I will let you know when I know more.

kbeefy, I did your recommended test this morning before work and as I suspected, in gear/out of gear makes no difference. Spinning the wheel by hand results in clak clak clak with no movement of the drive shaft. Does this mean that the ring and pinion are shot? I fear the worst.

My plan was to pull the front axles on Thursday and rip into the front diff over the weekend, but we may get some snow here in Colorado which may slow me down a bit.
_________________
1986 Syncro Sunroof EJ22
www.subagonsouth.com

IdahoDoug · Posted: Wed Oct 02, 2013 10:18 am Post subject:

You might drain the diff oil n see if the magnet on the drain has metal bit that will answer your question in 5 minutes.

DougM
_________________
1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader

insyncro · Posted: Wed Oct 02, 2013 11:04 am Post subject:

Send it to Daryl and get it rebuilt:

Image may have been reduced in size. Click image to view fullscreen.

I just received an upgraded locker front diff from him.

tim_ha · Posted: Sat Oct 05, 2013 7:29 pm Post subject:

I drained the oil and pulled the front differential off today. The oil didn't look too metallic and there was no christmas tree growing on the drain plug. In fact, there was hardly any buildup on it. Once it was out, I was able to feel/hear that the bad sound that it is making seems to be on the drive shaft side of the viscous coupler. By holding one output flange and spinning the other, I could feel that the ring and pinion are nice and smooth Cool

I will be opening it up tomorrow to see what I find on the VC side.
_________________
1986 Syncro Sunroof EJ22
www.subagonsouth.com

tim_ha · Posted: Mon Oct 07, 2013 10:29 pm Post subject:

Well, I finally cracked the front diff to see what the damage is. I found stripped splines on the VC input side and flattened splines on the flange shaft to match. Additionally, the grooved lock ring on the pinion side is all jacked up from. I assume it is from someone without the proper tools working on it.

Stripped viscous coupler splines.

Closeup stripped VC splines.

Flattened flange shaft splines

Good VC pinion side splines

Pinion splines

Bent star spacer

Did someone use a punch to tighten this?

Seriously?

I will pull the diff front cover to inspect the ring and pinion. Beyond that, advice on what to do? Any sources for a flange shaft? Can I replace the star spacer and grooved lock ring without having to adjust the pinion? May be time to call in a professional.
_________________
1986 Syncro Sunroof EJ22
www.subagonsouth.com

D Clymer · Posted: Mon Oct 07, 2013 11:50 pm Post subject:

I would just buy a complete used front differential assembly. There are several for sale in the classified section and they aren't usually a high-failure part.

D

tim_ha · Posted: Tue Oct 08, 2013 9:25 am Post subject:

Yeah, I have looked at those front diff in the classifieds. I guess that my only hang up there is that the condition of the VC will be unknown. My guess is that they will be fairly high milage and thus need to be rebuilt. I am trying to weigh all of the options right now.
~Tim
_________________
1986 Syncro Sunroof EJ22
www.subagonsouth.com

insyncro · Posted: Tue Oct 08, 2013 9:36 am Post subject:

Just sharing, but I've seen this before.

Pretty much why towing a Syncro with all four wheels on a trailer vs the fronts on a tow dolly is advised.

If you have the time, I would open up VC and see what the insides looks like.
I'm thinkin' it got really hot.

Sorry for your loss.

You do have options, but most are pricey.

tim_ha · Posted: Tue Oct 08, 2013 10:50 am Post subject:

Thanks, insyncro. I was wondering how on earth this happened. Luckily, I can point the finger to the PO as I have never towed. On the other hand, I have had the van a bit over a year and just now figured this out Embarassed

I will open the VC up and post some photos of what I find.
~Tim
_________________
1986 Syncro Sunroof EJ22
www.subagonsouth.com

sanchius · Samba Member Joined: May 03, 2007 Posts: 1455 Location: IN

insyncro · Posted: Tue Oct 08, 2013 12:54 pm Post subject:

Not accusing anyone, just sharing my experiences with trashed innards.
Maybe Gears or Daryl will confirm.

bac914 · Posted: Tue Oct 08, 2013 10:15 pm Post subject:

I have a known good front diff. I replaced it with a rebuilt one for really no good reason. The VC is a bit "aggressive" but works well. I've been in a house cleaning mode lately, so PM me with an offer....pick it up Saturday (I'm in Littleton) and you are off-roading again on Sunday.

tim_ha · Posted: Mon Oct 21, 2013 11:07 am Post subject:

Update on my front diff/viscous coupler:
I acquired a used front diff from a local Samba member. He was nice enough to let me open it up to confirm that the VC and flange shaft were good before making the purchase final.

I decided to pull the VC and flange shaft from the newly acquired diff and install in mine due to the bit of sludge in the oil and general grit as seen in the needle bearings here:

I cleaned out those needle bearings with a toothbrush and worked some clean gear oil in before installing in my diff. Here are the two flange shafts.

I decided to give the VC refill a try and have a seal kit and fluid on the way, thanks to IdahoDoug. I will start a new topic covering my rebuild procedure and results when complete.
_________________
1986 Syncro Sunroof EJ22
www.subagonsouth.com

tim_ha · Posted: Mon Oct 21, 2013 11:19 am Post subject:

I have two questions for those with front diff rebuild experience/knowledge...

First, I was thinking I would pull the front cover on my diff to inspect the ring and pinion wear. Reading the Bentley, I see that it says to loosen the left side r&p adjuster (can't remember the correct name right now) before removing the front cover. Does anyone know if this is necessary? I really just want to peek in at the r&p and don't have the tools needed to do the adjustment etc.

Secondly, I noticed that in addition to being all galled up, the grooved nut is installed upside-down. The chamfer should be toward the star spacer. Does anyone have any opinion or thoughts as to whether I should worry about this and replace with the spare diff parts? This is what I am talking about...

It looks like the star spacer is effectively bent into one of the grooves to keep the grooved nut from backing off. Again, I don't have the tools to deal with this, but wanted opinions on how important it is to the function and longevity of the diff.
_________________
1986 Syncro Sunroof EJ22
www.subagonsouth.com


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