A tale of 2 stealths

[jwscab]

Right. Use the old idler. The b4 shaft is what i would install. As you tighten the diff spin the diff halves so everything takes a nice seat and you dont potentially dimple the rings. I would adjust so its really hard to get the diff to slip by hand.

[GodSpeed]

I would adjust so its really hard to get the diff to slip by hand.

Oh, really? Like crank the diff spring (inside the outdrive) down all the way?

[RC104ever]

Yes and no. You tighten it all the way down SLOWLY as you don't want to flat spot the diff balls. Once you reach the bottom, you back it off a bit - I think 1/4 or 1/8 turn? And test the diff action. You may need to adjust it more once you drive it but that's the general idea.

[GodSpeed]

But what does too tight behave like and do to the transmission?

And what does too loose do?

[NickTheGreek]

I was talking someone the other day who's been racing for a very long time....I liked his idea...

He said he puts the the back end of a scissor (the little "things" that stick out) in each outdrive n slowly tightens the diff screw until he reaches the point where he can't turn the diff by hand and leaves it right there.
He says you don't want to back the screw out that 1/4 or 1/8 turn so the screw doesn't get used to backing out.
That's something I had never heard but it will be what I try next time I rebuild mine.

[jwscab]

Yeah essentially that's what i said. Sneak up on the tightening until you can no longer slip the diff with your fingers. Then install and make any minor adjustments if necessary.

[NickTheGreek]

Anyone ever use those garodisc slipper pads??

[GodSpeed]

We're all talking about the diff and not the slipper, right?

With that little t-nut totally bottomed out and the spring in the diff fully compressed (again, not the slipper spring), I can still turn the outdrives. It feels "crunchy" kind of with resistance, but it's not exactly hard to turn them.

Anyway, I guess I'll make it pretty tight. Thanks.

[NickTheGreek]

yeah, the diff.....

but what we were saying is not refering to tightening until not being able to spin each half the opposite way....

....Its holding the outdrives in place and tightening the screw till the point you cant turn the diff gear itself by hand....

[GodSpeed]

yeah, the diff.....

but what we were saying is not refering to tightening until not being able to spin each half the opposite way....

....Its holding the outdrives in place and tightening the screw till the point you cant turn the diff gear itself by hand....

OHHHHHHHHHH!

So you have to do this with the case open and the differential alone in your hands?

How tight should spinning the outdrives in opposite directions feel? Mine are tight (now that I've been cranking down the bolt & t-nut) and kind of crunchy. The crunchiness I feel is kind of odd. I used the proper black grease too.

Too many questions from this dumb guy. I'm going to crank it down and back it out 1/4 turn just like the instructions say and leave it at that.

FTR, I'm using a 6565 case, 6570 idler and a B4 top shaft and my transmission spins like butter with no contact on the slipper plate either. Pretty damn happy about that.

[NickTheGreek]

It's all good mah brotha....I'm in the same boat..learning as I go along.

Yeah, it would have to be outside of the case when you're just holding the diff by itself to do that.
Personally I've never done it that way yet myself , but it seems like a pretty good method that I will try next time.

I just do the 'tighten till I feel resistance ...tighten a lil more real slow n then back it off a hair' ...Seems to work fine, although I don't know what I'm doing....
Someone with experience would have to chime in to explain exactly what it is "someone's" searching for when tightening a diff.

[jwscab]

essentially, you are looking for the least amount of spring tension to give you adequate 'grip' on the diff balls for a given power level. Any tighter than necessary translates to the diff spring weakening, and potentially over-stressing the diff screw. At the same time, the diff balls/rings and especially the thrust bearing parts will wear prematurely, resulting in rough, notchy and inconsistent performance.

[NickTheGreek]

Ah...got it.

I gotta question pertaining to diffs....
On my Worlds re re ....The thing was (n still is) running great. Diff seemed real smooth.
After I had built it and ran the car for a while I had never fine tuned it....Being that I've heard it's good to check the diff after your first few runs n readjust it accordingly which I never did....A few days ago I figured I'd just tighten it just a hair.
Car still runs fine....but now if I hold the car and turn one wheel by hand, sometimes the other one spins in the same direction.....Or while I'm spinning the one wheel by hand, I can't even explain it....it feels like something disengages and then catches again.....
What causes the change from spinning one wheel by hand and the other going in the opposite direction to turning it by hand a few days later and the opposite wheel is spinning in the same direction??

[huminski]

You originally had the diff tightness in a spot where it was loose enough to be consistently held in place by the motor magnets, in other words it would slip (not fully slip but engage opposite side counter rotation) every time because it was not tight enough to overcome the motor magnets.

Now that it's a bit tighter, sounds like it is right on the edge of slipping (opposite wheel spins the wrong way, diff gear not spinning and motor not turning) and then sticking (opposite wheel spins the same way, which means the entire diff is turning and therefore you are also spinning the motor) which is why you are feeling this distinct difference in tension.

I would guess the diff is a bit too tight right now, might start scoring the pressure rings or flattening your balls (that's the worst, lolol)

[huminski]

...........and I just realized your post was like 4 months old

Hope it still helps.