Odd tranny combo...

No, not hairy legs in high heels...

I built up a Honda drivetrain, including the transaxle, and ran into completely contradictory requirements.

A WaveTrak LSD, a gear-type LSD with some sort of clutch-type element in it, was installed. The mfg said to continue using whatever oil the transmission mfg recommends (10-30 wt), stressing, ordinary oil.

Also installed was a new gear set, with 1-4 being straight-cut, with dog-engagement "synchros."

Now the problem: The gear manufacture said to use something like Redlines "Shockproof" gear lube. Meanwhile, the LSD mfg specifically said NOT to use Shockproof gear lube.

At the moment I'm still running plain-ol' 10-30 wt because I can't figure out what to use. I suppose I could look at it from a money standpoint, that since the gears are a whole lot more expensive, I should side with that mfg. However, the LSD guys said that using Shockproof stuff will cause their LSD to end up acting like an open differential... that's no good.

So I'm throwing myself at the feet of the collective conscience here: does anyone use a combination of a gear-type LSD, straight-cut gears, and dog-engagement, and what oil are you using... and how's it working for you?

How do you do? I

See you've met my

faithful handyman...

In a clutch type LSD, I can see how using the wrong oil might make it not engage, but a Torsen type?

I'm not following how the wrong type of oil would make it work like an open diff.

This is what LSD modifier is for. Use the shockproof stuff, and add the recommended amount of LSD modifier.

But that's the problem. The WaveTrak mfg specifically says No shockproof stuff or LSD modifier. From their website:

What gear oil should I use? Use the "factory fill." In other words, use the gear oil spec that your car manufacturer recommends for your car. The Wavetrac® is compatible with virtually all factory-installed gear oils used today. If you are racing your vehicle, and wish to upgrade the gear oil to improve performance or durability in racing conditions, choose the oil carefully: be aware that some gear oils have additives that are not recommended for use with your Wavetrac®. Some have friction modifiers designed for limited slip differentials. These modifiers generally increase slipperiness and are intended to reduce clutch disc chatter in conventional clutch-type LSDs. Some gear oils such as Red Line Oil's Shockproof® type have microscopic solid particles in immersion in order to "cushion" transmission components, acting as an extreme pressure agent. The Wavetrac® and all helical gear differentials in general, operate using friction. The friction generated between its internal gears and its housing are what allow this type of differential to function. Gear oil additives that drastically reduce friction will actually reduce the performance of gear differentials. The internals of the diff get too slick to generate adequate friction - reducing the differential's effectiveness - reducing its ability to drive both wheels. In conclusion, when using a Wavetrac®: •Use factory spec oils for your car •Avoid gear oils with limited slip additives. •Do NOT use RedLine, Shockproof® or similar gear oils.

I would run something thicker and preferably meant for gears,but not friction modifed for a LSD(GL-4 ONLY gear oil, I think Napa can get it), or at least a good 20w50 motor oil. With dog engagement you don't really have to worry about keeping synchros happy, just keeping the gears alive and the diff happy.

Use the Shockproof. It's needed to protect the gears and the dogs/sliders, which are more important than the clutch packs in the diff.

IF the clutch packs wore out, then the only bad thing that happens is you lose the preloading feature and the diff becomes a regular helical diff. But even that is a pretty big "if".

Bear in mind that Shockproof wears out and needs to be replaced every 5000-6000 miles or so. The shock-damping effect is produced by small calcium (I think...) bits in it and they break down rapidly. I generally wait for the nice bright blue or bright red color to turn to a sickly purple and then change it.

IMHO No!
The requirements for tranny gears (straight cut or otherwise) do not include 'friction modifiers', and are far less critical than limited slip applications.

The only reason gears would need something more than good quality straight oil is for the kind of sliding mesh that is seen on hypoid and similar gearforms.

Your tranny gears do not employ hypoid gearforms.

But it's your car, your call.

It's probably desired for protecting the dogs, which do get banged around a lot.

A cynic would think that maybe the manufacturer knows that they don't do such a good job of heat treating the gears/sliders or used a cheaper steel alloy and are crutching it with fancy oil...

Shockproof isn't really a friction modifier, it's an impact force modifier. Helps a little bit if you have a gear-breaking problem.

I'm also running the oem 5th and 6th, just to make things more challenging (meaning that factory synchros are on them.)

Reading around, some people are using Torco RTF, but I haven't checked it out yet.

Imo, actual gear faces are lowest priority. They'll work with pretty much anything. I honestly think lube choice is more critical for bearing wear than gear face wear. So i would do whatever the LSD manufacturer wants.

Vigo wrote: Imo, actual gear faces are lowest priority. They'll work with pretty much anything. I honestly think lube choice is more critical for bearing wear than gear face wear. So i would do whatever the LSD manufacturer wants.

Ditto. I'd follow the LSD recommendation and change the fluid frequently considering the gears won't tolerate crummy fluid, from the sounds of it.

Bryce

Brett_Murphy wrote: In a clutch type LSD, I can see how using the wrong oil might make it not engage, but a Torsen type? I'm not following how the wrong type of oil would make it work like an open diff.

The wavetrac is a worm drive with a clutchpack. They differ from the torsen/quaife in that if one tire is in the air, it won't get 100% of the load. The torsen/quaife will both spin an unloaded wheel like an open diff would.

I guess you could call it a clutch type ATB.