210: Gearbox binding with gear diff?

[Origineelreclamebord]

Hi everyone,

Today I got my gear diff in. I built it as per instructions on TD website. I just put the diff in and... it won't move freely inside the casing when it's tightened/closed. Even after removing the copper shims it's just tight.

Any thoughts what's at fault and how to solve it?

[mattr]

If you overtighten the bolts running though the gearbox, it binds. Try backing them off 1/4-1/2 a turn.

And the gear diff doesn't need the shims AFAIK.

[jo90]

Double check you have seated both the large bearings fully home on the casing. I found when i bought a new diff the casing was very tight where the bearings went on and one wasn't seating full home against the case correct, causing it to get nipped up on the gearbox case when closed up. A quick rub of wet and dry around the GD casing where the bearing sits and it goes on tight, but goes fully home. No more binding.

[Origineelreclamebord]

I am no Hulk and I don't try to be.

I have to loosen the gear casing until you ca see a gap between the two parts for the diff not to bind. In fact, upon the first build I was having problems with a layshaft spacer that caused the layshaft to bind... so I'm starting to think the gear casing is actually a little off. I wouldn't be too surprised about that, it came from the very first batch, and there were other parts with problem areas as well (wheels warped to a degree that they're not of much use for racing).

Could anyone measure their diff's width between the surfaces against which the bearings sit (without the bearings or shims), like this:

Ball Diff:


Gear Diff:


On my diffs it's clear to see the gear diff is wider. With shims on the ball diff and none on the gear diff there's still almost 0.4mm between the two. However, it could well be that the gear diff is just wider and my casing too tight, so I need to need to make sure.

I've also contacted Durango about this.

[mattr]

Looks like a dodgy diff.
Think mine is "about" 19,5mm across the bearing seats (not written the measurement down), the first, oversize one that i had was 19,8mm (i had this dimension written down in a PM, and was told it was probably one of the early oversize ones).
So over 20mm = probably a bad diff, it may be part of the first batch.

(and the gear diff should be a little wider, not that much tho!!)

[pugboy]

Does the diff still bind without the idler gears in place? There are a couple of possible causes but I grappled with a similar issue. It can be caused by what the posts say above or if you have nipped the diff screws a little too tight it can cause a slight distortion of the diff gear thus causing a tight spot in the mesh with the idler. Good luck and hope you sort it.

[Origineelreclamebord]

Thanks for the suggestions everyone

Unfortunately I can't check all these things until friday night or saturday, but I'll definetely look through them. I also hope Durango respond to it soon.

The car is from the first batch of DEX210s, the gear diff was bought a few days ago at JEModels - I don't think they still have diffs lying around from the first batch

[AndyG]

had the same problem, so never went back to the gear diff.