Gear Box - Tight
 

Right, im rebuilding the car ready for sunday. I've built up the gear box in MM4 format. All the casing, bearings, shafts etc clean and all in 100% order (no dodgy bearings etc). Layshaft spacer is one of the new ones so its in 100% good nick too.

Put the gears in, along with a gear diff. Before closing the case up all the gears spin fine. close the two halves together and it is binding like mad to the point Im having to use reasonable force to turn the gearbox over from the diff outdrives. Take it apart, re-check gears all spin in both sides of the gearbox haves, put it together again, same thing.

I even removed the shims from either side of the 2 idler gears to create space, still same thing.

Has anyone else come across this at all ? Im wondering if the gearbox has warped somehow in a knock.

cheers

You broke it lol

Had the same issue in the past.
No spacers on the gear diff.
Put the gear diff only in the gearbox and see if there a bit of backlash when pinching the gearbox together (with your fingers).
If that is not the issue, put all internals in, screw all screws in and loosen them up half a turn.

Check Main Gear
 

It might be that you have tightened the screws on the gear diff too tight and warped it. Check the main gear and loosen the screws slightly.

Does it pinch on a section when you rotate it?

Think the gear diff meshes a bit tighter to save the drive train from the extra stresses the gear diff puts on the rest of the gearbox. I have exactly the same (no shims). As already suggested, tighten up case screws as usual and then back off a fraction.

I have actually done the screws on the GD tight, i will try to back them off a bit and try again later once home incase i have warped the gear.

cheers guys

Had this problem when i used the new layshaft spacer. I backed the case screws at the top of the gearbox case off 1/4 turn and it is fine

Mine is the same, and originally had the same solution but seems to have got worse since i rebuilt it. I was thinking it was down to the layshaft spacer but I've swapped that. I think it's just down to gearbox case manufacturing tolerances.

I had previously run with the new layshaft spacer, and it is the same GB casing as I have been running for a few weeks.

I will try tinkering tonight and work out if it is the GD warping or something else. At least I will have a fun thursday night indoors haha :woot:

Is it an early gear diff ? There was an issue with the very first batch of casings that meant the mesh was too tight, Durango replaced them at the time.

No idea mate as it is second hand :cry:

Is there any way to tell ?

I have recently swapped to the ball diff from a new style gear diff and had the same problems so don't think its diff related.

Yes if you put your ball diff in again and everything runs smooth then the gearbox is OK but the diff not.
Yes you can measure the diameter of the gear diff and there is a difference of about 0.2 mm between the first and second generation.
If needed I can measure it tonight for you.

Right, just took it apart and it turns out one of the idler gears is running tight. Both bearings are fine, no marks on the idler pin, but with it in the gear box tightens up. Replaced it and the box is now as loose as drunk Romford girl.

Thanks for the input though guys, this might help someone later with the same issues.

I had this with my car!

the fix was 0.5mm shim x 3 between gearbox and motor mount.

The motor mount was crushing the layshaft bearings together.

My car is so much faster now :thumbsup:

My friend tried it too and he also agreed much better!

Can you get a pic? Did you back the screw off half a turn anyway or can you tighten them hard now?

This sounds like a good idea; I am still loosenings the screws for half a turn!
If the motor plate is also crushing the bearing holder in my car, then this is probably the solution!:woot:

I had a noticeable tight spot on my gearbox and took it apart about 100x with different shims and stuff but with no luck.

In the end I was convinced the layshaft bearing had gone but just as a last resort flipped over one of the idler gears (even though they do not look worn at all) and reassembled and it's now as loose as a Geordie lass:wub

Yep with the shims installed you can tighten the screws right up and the gearbox is super free ;)

I will post a pic tomorrow if you really want.

You put shims on all 3 bolts right?
A pic is not only for me there might be others that want it and aren't that good at english