Fitting a viscous gearbox to an L series

tambox · Post by **tambox** » Sat Oct 06, 2012 7:22 pm

Has anybody fitted a viscous (early Liberty) box to an L series?
Thinking about swapping the Liberty bits into an L housing.

T'subaru · Post by **T'subaru** » Mon Oct 08, 2012 12:48 pm

You can makeup hybrid axles.

A fella on usmb has the inner races made by rockwell to combine l series / liberty and wrx axles. The axles pictured are for a 4.11 vlsd '95 wrx rear diff going in my '89 wagon.
His user name is suberdave
cheers

YouTube · Post by **El_Freddo** » Thu Oct 11, 2012 10:30 pm

tambox wrote:Has anybody fitted a viscous (early Liberty) box to an L series?
Thinking about swapping the Liberty bits into an L housing.

I'm sure it's been done. I've gone the other way and slotted the PT4wd L series gearsets into the EJ front casings while retaining the rear housing for the PT side of things.

You'll be able to do the gearbox mods easily, just retain the EJ rear casing for the AWD. You should be able to work out the speedo drive requirements to make the L series speedo correct - or use the Gen1 3.9 AWD gearbox with a 3.7 R&P set and the L series speedo gear to make it all L series "compliant".

Then you'll have to knock up a new gearbox crossmember unless you can work out how to use the EJ setup; gear linkages will need to be sorted as well as a custom tail shaft front piece.

It'll be a great setup once you've got it sorted.

Cheers

Bennie

tambox · Post by **tambox** » Mon Oct 22, 2012 8:38 pm

Ok, got around to it on the weekend.
Stripped a gen 1 gearbox, put it into L series housing with L series low range.
Running Liberty lower ratio gearset, with 3.9 diff.
Viscous coupling used as middle diff.
Fitted it to an L series wagon

Works well, had to guess with the speedo gear, as it was now a 3.9 diff, over reads by about 8%, safer than under reading.

The major improvement was the feel of the gears as you select them, much, much smoother and easier than an L series.

Works surprisingly well for gentle 4wd work.
I get a slight shudder under hard acceleration in 1st gear, around tight corners. I was told it was because L's are lighter than Lib's.

Easy to do the box, a bit of creative construction to make it fit.

nncoolg · Post by **nncoolg** » Tue Oct 23, 2012 6:02 pm

How do you get the diff adjustment right in the different housing so it doesnt whine?

tambox · Post by **tambox** » Wed Oct 24, 2012 7:26 am

Strip, check and inspect the box before you start.

Setting the diff up can be difficult, it generally depends on what other bits you have changed as well.
The simple way to do it is to swap complete diff,gears and shims set between the housings.
BUT
Replace/check the main bearings at the same time (so everything sits where it should).
Usually do the seals and 3rd gear synchro.
This generally works, provided they are "standard" gearboxes that have never been stripped before and are close in year of release, ie L series should use Gen 1 boxes for swaps.
Then tighten the diff back lash, as per manual.
That way is risky, but usually works.

A simple way to check the above method, to ensure it is going to be right is to "blue" the crown/pinion, before you remove it from the original box, then set it to run in the same place in the new box. Refer to manual for how to do it.

If you change gear sets or use parts from boxes that have been stripped before or not close in year/model, then read the manual. Gearboxes that have been played with before can be found to be set up wrong or missing bits, unless you know the boxes well, stay away from them.

Sorry, its harder to write it down than do it, do not use this as gospell, but it will give you an idea on what is required.

YouTube · Post by **El_Freddo** » Sat Oct 27, 2012 4:32 pm

So how does the L series go with the AWD from the liberty? Keen to know.

Cheers

Bennie

tambox · Post by **tambox** » Sun Oct 28, 2012 11:32 am

Brilliant.
This one is behind an ea82efi, compared to normal front wheel drive, it is much better, especially in the wet.
The box changes more smoothly.
Compared to lockable centre diff 4wd, for gentle 4wd work and on road, very similar, although the viscous does grip better than the unlocked centre diff.
The 3.9 diffs and low ratio gear set work well with 14" wheels.

When I get another gen1 box, I will do the same to my daughters L, very worthwhile.

Mitchhsj · Post by **Mitchhsj** » Mon Oct 29, 2012 4:34 pm

that will be the combo I'm looking for when i put my ej20t into my l series, sounds great mate

YouTube · Post by **El_Freddo** » Mon Oct 29, 2012 6:33 pm

Mitchhsj wrote:that will be the combo I'm looking for when i put my ej20t into my l series, sounds great mate

Except that you won't have to re-case it in the EA case - tambox is still with the EA82...

tambox wrote:The 3.9 diffs and low ratio gear set work well with 14" wheels.

What tyre diametre? I'm running a 14 inch rim too - but with 27's.

Also, I was thinking that if you get the gen 1 with the 3.9 ratio diff, swap it to a gen 2 front diff ratio of 3.7, L series speedo gear and you've essentially got an L series AWD from an EJ AWD. Make sense?

I think this would work because my understanding is that subaru changed the diff ratio to match with the larger diametre tyres that the liberty uses, this then went back to 3.7 ratio in the gen 2's when they realised the EJ22 would be able to push the subi without an issue and still get good economy - a tweaked ECU tune was probably also used in this case. My theory as to why this would work anyway

Cheers

Bennie

tambox · Post by **tambox** » Mon Oct 29, 2012 6:59 pm

As its our "round towner", it has road tyres, 195/70/14.

Your plan for a bitsa box should work, but make sure you take into account the number of speedo gear drive teeth on the 3/4 gearset, as these vary.

The more bits you swap/mix, the more carefully you have to check alignment of the gears, more work.

I have built boxes out of unknown bits, they work, just take a long time to check/setup.

I have never needed to keep a record of the variations in speedo gears or 3/4 speedo drives and what boxes/wheel sizes they match. I do know some of them. If required, I would do the mathematics with what I had at the time.

Hense, one of the reasons I built the box the way I did and I prefer the 3.9 diff. Well except they are easier to break:)

YouTube · Post by **El_Freddo** » Mon Oct 29, 2012 7:13 pm

Also, what exactly is needed to be modified for the gearbox to be fitted - I'm after "intimate details" as in lengthening of the gear lever rods etc etc.

I would say the gearbox crossmember, tail shaft lengthened, and if you didn't swap the diff output shafts to 23 spline you'd need to source the 25 spline drive shafts/cups

Cheers

Bennie

tambox · Post by **tambox** » Mon Oct 29, 2012 7:29 pm

The gearbox worked out to about 50mm longer.
The gear selector needed to be shortened, the tailshaft was shortened as well.
For the high/low, I used the same parts as the L series, but welded a nylon bushed tube to the top of the inspection cover for the rod to slide in. This meant the high/low linkage was in the same place.

I welded a peice of 10mm steel plate to the bottom of the L series gearbox mount, which extended out to the new mount. This twisted to much so I added another plate with "arms" on it that went up to the threads in the tunnel behind the gearbox, was the "tailshaft catcher plate" mounts.

Its solid and works well.
I'm sure there are many other ways to do it, but coming from a farm, you use what you have, or walk.

tambox · Post by **tambox** » Mon Oct 29, 2012 7:30 pm

Yes I did swap the outputs.

tambox · Post by **tambox** » Fri Nov 02, 2012 4:13 pm

Did a bit of viscous gearbox "evaluation in the wet" over the last couple of days, I can hang the tail out on tight wet bitchumen corners.
That feels really weird in an L series.

YouTube · Post by **El_Freddo** » Fri Nov 02, 2012 9:33 pm

I did that in my mate's liberty last week through a dry roundabout - that was a good bit of fun! Got new tyres now so the baldies that were on the rear are gone, no more of that - which is not a bad thing, on rails pushing hard through corners is a put load of fun!

Cheers

Bennie

tambox · Post by **tambox** » Sat Nov 03, 2012 9:02 pm

A little bit more power than an EA82efi, would make it more fun.

As Bennie asked earlier, how it went?
Which leads to a review of the differences in L setups.

Driving an L series lifted wagon hard, under power, in the wet, on bitchumen;
L series EA82 carb - understeers on corners and spins on take off.
L series EA82efi, viscous box - oversteers on corners, no problems taking off.
L series EJ22, LCD box, unlocked -understeers on corners, no probs take off.
L series EJ22, LCD box, Locked with rear LSD - understeers on corners, like glue on take off.

Tyres and a million other things will affect this, but the basics are;
1. Front wheel drive is, well, not very good.
2. Viscous distributes the power fairly evenly.
3. EJ22 LCD unlocked, tends to spin inner front wheel.
4. EJ22 LCD locked, LSD pushes it straight ahead.

Which I guess leads to the conclusion, highway driving, Viscous rules.

There are better systems, but I don't think you will see many L series equipped with them.
It has been a fun worthwhile project.
Thanks for the interest.
Greg