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Mon Jul 07, 2008 8:22 pm

Hey,

So I know that I'm still learning a lot about the variations in the different Syncros but I wondered if anybody had every but a locking diff in a Syncro that didn't come with one? I can't seem to find the parts on gowesty.com suggestions?

Follow up question would be which of the diffs actually lock up the front or the rear? I have read conflicted articles on both.

Also had anybody ever put a decoupler in? is the install time really around 4 hours?

Thanks!

Tue Jul 08, 2008 5:41 am

Ok, to tackle the questions one at a time.

Yes you can put a locking diff. in a non-locker Syncro. You need to have the transmission rebuilt and the parts installed, you also need to install the vacuum system. Don't go to GoWesty for this work whatever you do. Lucas makes you forfeit the entire $2000 core deposit if you send him a non-locker and you received a locker, I believe our quote was over $5500 for a rebuilt gearbox. Darryl at AA Transaxle can set you up for a reasonable amount and a good rebuild. You might need to source some of the vacuum parts yourself, the tank and console are the biggies, but theSamba classifieds are a good source for these. Van-Cafe can also get you all the little fittings and the check valve. Somewhere in theSamba archives there is the '86 service manual that has a good description of the Syncro system.

There are two setups for the diff. locks. In the US VWoNA decided only have the rear locker as an option. That means that on the vans here you can lock the two rear wheels together and push yourself out of the mud. In the rest of the world (except maybe Canada) you could also get a front locker, this is kind of cool since now you basically have to have no traction on all four wheels to get stuck. Front lockers are pretty rare in the US and fairly common in RoW, it is a nice option and you can retrofit it if desired.

We installed a decoupler in our '86 non-locker this spring. It was not a 4 hour job. Running the vacuum system took about 2-3 hours and installing the decoupler took 4-5. Finding the wiring harness to connect to the decoupler took the longest. The seal started to leak as soon as we put fluid in it so Dad had to pull the nose piece again an reseal it. Best modification you can do to a Syncro. It makes it a joy to drive in parking lots and it is killer offroad. We did not put in a solid shaft so we can still leave the front end hooked up on the highway if need be. I lock things up when there is a bad crosswind and I am getting blown around. Now all I need to do is get one of the more aggressive viscous couplings from Europe and we are set.

Calmer more seasoned minds will hopefully weigh in and add their thoughts but this should get you started.

Paul

Tue Jul 08, 2008 9:32 am

I wish there was an option for all 3 conditions

Original (viscous coupling for gravel roads, ice)
Decoupled (city driving, and the freeway slog)
Locked up solid (no delay for driving up onto leveling rocks!)

Does anyone know if this has been done? It seems a bit much to ask.

Tom

Tue Jul 08, 2008 9:38 am

Sorry for the hijack (above).

I had a situation with the rear locked, backing down a steep hill I was unable to turn the van (front wheels just slid sideways as all of the weight and traction if this little box was biased on (weighting) the solid rear axle). It made me think that for conditions where you have all 4 tires on the ground, that the Peloquin is a better and easier (perhaps less $ too) option than a solid locker.

Daryl at AA transaxle might be able to guide on this. The Peloquin would be ready at all times like a VC, you wouldn't have to do the little 'locking dance' to get in and out.

Tom

Tue Jul 08, 2008 6:11 pm

Sodo wrote: I wish there was an option for all 3 conditions

Original (viscous coupling for gravel roads, ice)
Decoupled (city driving, and the freeway slog)
Locked up solid (no delay for driving up onto leveling rocks!)

Does anyone know if this has been done? It seems a bit much to ask.

Tom

Sounds like you want front/rear lockers, and a decoupler, if you dont switch your VC out for the solid shaft you can have all three situations listed above.

It's a combination that many people put into their syncros.

Tue Jul 08, 2008 9:16 pm

so this is a completely uneducated question, but would it be at all possible to put a locker in on a 2wd?

Wed Jul 09, 2008 5:47 am

I believe you can put a rear locker on a 2WD. I saw on GoWesty's site that a 2WD vehicle they sold had a rear locker put in. Hold on for sticker shock, though when you look at this.

http://www.gowesty.com/sale_details.php?id=1006

Wed Jul 09, 2008 8:41 am

rfoubi wrote: so this is a completely uneducated question, but would it be at all possible to put a locker in on a 2wd?

My brother put a Peloquin differential in his 2wd and he is very happy with the performance. http://www.peloquins.com/products_094.html

The problem with a locker is you're not supposed to lock it AFTER getting stuck, you're supposed to lock it before you drive into the mud. Which may not work very well most of the time you need it. And a locker can cause problems on ice, ENSURING that you will break traction if not traveling perfectly straight.

And a solid rear axle will "push" the front wheels which are not "pulling" so will cause steering problems. A rear locker without the front wheels "pulling" sounds like a strange handling vehicle, the last thing you want when you're 'stuck'. Would be interesting to hear a Syncro driver's experience with this (decoupled + rear locked)

To put a locker on a 2wd, you have to first locate a Syncro tranny which would be very expensive at least $5000 (but you would have a granny).

The Peloquin differential is about $1300 but needs installation....

Wed Jul 09, 2008 9:38 am

foodeater wrote: Sodo wrote: I wish there was an option for all 3 conditions

Original (viscous coupling for gravel roads, ice)
Decoupled (city driving, and the freeway slog)
Locked up solid (no delay for driving up onto leveling rocks!)

Does anyone know if this has been done? It seems a bit much to ask.

Tom

Sounds like you want front/rear lockers, and a decoupler, if you dont switch your VC out for the solid shaft you can have all three situations listed above. It's a combination that many people put into their syncros.

The real reason I thought of this is because the VC has a 'delay' that causes the rear tires to spin a little before the front wheels start to assist. I noticed this when backing onto a stack of 'leveling rocks' (camping on a hillside). The delay is noticeable. And driving in sand, it reverses better than going forward, because of the delay of the VC. Basically just a discussion of 4WD for discussions sake, which I enjoy too.

A much easier solution for my leveling problem is to maybe use a jack! .....not a $thousands spent on differentials. Realistically it already goes anywhere a 4WD camper can be expected to go....

Thu Jul 10, 2008 7:39 am

Here are my thoughts, open to correction, or differences of opinion

1. A solid shaft instead of a Viscous Coupling,

pros
coupled solid shaft transfers equal power to front and rear,
coupled solid is superior in sand, tail does not sink like with VC
decoupled reduces resistance to turning, especially when parking
decoupled allows use of a mismatched spare tire
decoupled saves tire wear
you CAN couple on pavement, and obtain the All Wheel drive traction that a viscous provides
you CAN couple on mountain roads with curves and patchy snow
you do not have to only use the coupler on dirt or deep snow

cons
people think, mistakenly, that coupling is forbidden on pavement
coupling and decoupling is not automatic, the driver has to do it

2. A viscous coupling instead of a solid shaft
pros
my daughter can drive my syncro

cons
front wheel power is always less than rear wheel power, a problem in sand and deep snow
tires wear more than a 2wd setup
steering is stiffer
parking is harder
you cant run a spare unless its been in rotation and is exactly the same size as all the other tires

3. rear locker
pros
can engage to get out of a spot where one rear and one front are spinning, this is strictly for offroad use

cons
expensive add on
driver must engage and disengage, not automatic
will increase sideways slippage on ice or sideslope, but ice is slippery in 2wd too

4. front locker
pros
will give both front wheels ability to turn even if one of them is slipping, offroad use only

cons
expensive add on
driver has to remember to turn it off and on

5. Peloquin or Limited Slip Differential
pros
transfers power to the non slipping wheel,
power transfer is automatic, no driver button pushing required
you CAN buy a LOCKABLE LSD

cons
more expensive than a locker
you cannot turn off the LSD, such as in sand
power transfer happens automatically, and is not truly locked, power pulses back and forth between the slipping wheels, such as on sand, and will dig you down really quickly
There is a concern an LSD would accentuate slipping on ice
if you drop a wheel in a hole the sudden transfer of power to an opposite wheel can push you further towards the hole side

6. using a decoupler with a Viscous Coupling
pros
you get ease of parking,
ability to use a mismatched spare
you can turn all wheel drive on or off whenever you like

cons
power transfer to the front is less than to the rear
in sand the rear of the van rides lower than the front, more likely to get stuck

Thu Jul 10, 2008 8:01 am

this is what lockers are for. Im not sure if he has a VC or a solid shaft, try to watch how fast the rear wheels turn relative to the front.

watch his wheels turn even in mid air, thats the lockers

http://youtube.com/watch?v=iGq_6avRbYE

btw, on a 2wd Van, adding rear locker makes the vehicle MUCH more capable on dirt

without lockers, each axle only has to have ONE wheel break into a spin, to totally stop any power going to the other wheel on the same axle

so a 2wd van with locker, can have 2 driving wheels, instead of just one.. this is only on loose surfaces..

NEVER run locked on pavement

so, there is a risk to adding a locker, if anyone else drives your van, they can blow up your drivetrain by pulling a button

Thu Jul 10, 2008 11:58 am

YES! Thanks for pulling that all together. Alll makes sense.

I like the ones that work with no extra input. For example "my daughter can drive it" that's a good thing.

OTOH I currenlty have 5 tires in rotation, consequently am always scared I'll mess up the schedule.

Anyway, just remember that AWD adds complication, and..... you can always buy more stuff to make it more complicated.......

Thu Jul 10, 2008 8:05 pm

Ok,

So if I install the decoupler and replace the VC with the solid shaft and I have no front locking diff or front limited slip diff how will the front wheels turn on pavement, snow, ice, etc.? Would I have to install a limited slip diif to use the solid shaft replacement?

Really good info so far, Thanks guys.

Thu Jul 10, 2008 8:23 pm

the front wheels can each turn at different rates because you (with no front locker) be running an open differential (where the wheel with no traction spins). with the decoupler engaged and a solid shaft in place of the VC what will always be the same is the torque split between front and rear differentials. Where the VC can allow the front or rear wheels to have more torque the solid shaft always engages both diffs equally.

Thu Jul 10, 2008 10:35 pm

I have not seen any Native US Syncros with stock front lockers. The lockers that I have seen are in England, Sweedan, Finland, Norway and Germany. I am certain they are all over Europe, though those are the only contries I have traveled to. I know a guy in Santa Cruz, CA that brings a couple of the front lockers into the USA a year.

Fri Jul 11, 2008 6:46 am

> Would I have to install a limited slip diif to use the solid shaft replacement?

I do not recommend you use a solid shaft, unless you have both front and rear lockers.

I suggest instead, that you keep your VC, and if you want a rear locker, buy a tranny with a locker.

bear in mind that VC's and LSD's are automatic in their engagement and disengagement, although a VC never disengages completely.

so you have 2 different classes of drivetrains, self engaging, or driver engaged.

the self engaging order of preference is
1. VC
2. rear LSD
3. front LSD
4. no decoupler

If you go to a driver engaged system, the order of preference is

1. VC
2. rear locker
3. front locker
4. decoupler
5. only after all the above are already in place, then maybe get solid shaft if you are sure you want to abandon the VC

look again at the Gordon Craig video, as he backs up it seems to me his rear wheels spin more than his front ones, implying he has a VC, even for the extreme terrain he is crawling up, with both front and rear lockers engaged..

Most people who have a VC dont have a decoupler. Rear lockers are much more important than a decoupler. Dont even think about a solid shaft until after you have both front and rear lockers.

Jon O'pinion

Wed Jul 16, 2008 1:10 pm

Jon and everybody else,

So what is the best option (combination of limited slip/locking/de-coupler/etc.) for 90% snow on the way to the ski area and 10% light off-road?

B