1.9 differential back lash settings.

[Daspete]

Hi guys

Had my differential rebuilt a couple of years ago whilst rebuilding most of the car but only got the car back on the road in may and it's apparent they did a bad job.

I get a clunk from the diff when I change direction and from a spirited pull off from stationary. Seems there's quite alot of backlash which I did ask them to check. I didn't really have any before but now it does.

Had an oil leak from the diff too. On closer inspection I found the drive flanges are literally floating in and out with no resistance so the retaining rings must be missing or incorrectly positioned as well.

Decided I'm going to sort it myself and I have the equipment.

However does anyone know how much backlash is permitted in that diff?

Assuming it's just adjusted using the large shims under the side plates?

Thanks in advance

 

[Lee]

We couldn't find the torque spec's years ago when we looked, so we found a local guy who rebuilds them for us for a small fee.

Those side shims keep the crown and gearing central, the pinion gear crush sleeve is the spec you likely need, this controls the play between the crown gear and pinion gear. We have actually found with the two last diff's we've rebuilt its been failing input bearing causing the backlash.

 

[Daspete]

That's useful info, cheers.

You can get different thicknesses of the shims and some diffs that's how you change the backlash, that's why I thought it would be that.

Is the pinion difficult to set?

 

[Lee]

It's actually very simple to do with some basic tools and engineers blue to check engagement.

Your diff is a small case diff but essentially the same.

BMW E30 Limited Slip Differential Restoration - YouTube

 

[Andyboy]

A good used diff sounds a better idea.

I've rebuilt 20 or 30 BMW diffs and they are so well made that even after a bearing change, they rarely if ever need setting up. For your diff to be that bad they've really ballsed it up. Just bin it and fit another.

 

[Andyboy]

the pinion gear crush sleeve is the spec you likely need, this controls the play between the crown gear and pinion gear.

Not really.

The pinion height is set by the shim between the big pinion bearing and the diff case. The crush tube is there to set bearing preload, nothing else. This is set either by 'feel' (you get it after rebuilding a few) or by torque wrench until the pinion bearings have no play and the flange requires just 0.7 nm to turn without the oil seal fitted. Once set, the flange/pinion/nut are marked, the flange removed and the seal fitted.

What may have happened with this diff is that the clowns who did it fitted the output flange shims on the wrong side - this would have the effect of moving the crownwheel/diff away from the pinion and massively increase backlash. But it could be anything. I'd start by grabbing the pinion flange and trying to move it up and down - any play there means they haven't done the pinion up up correctly.

 

[Daspete]

From what I've seen around the net it is those shims on the side that alter the backlash. Though I'm finding conflicting amounts of permitted backlash. One place says 0.127mm and another says 0.06 to 0.1mm

 

[Daspete]

Not really.

The pinion height is set by the shim between the big pinion bearing and the diff case. The crush tube is there to set bearing preload, nothing else. This is set either by 'feel' (you get it after rebuilding a few) or by torque wrench until the pinion bearings have no play and the flange requires just 0.7 nm to turn without the oil seal fitted. Once set, the flange/pinion/nut are marked, the flange removed and the seal fitted.

What may have happened with this diff is that the clowns who did it fitted the output flange shims on the wrong side - this would have the effect of moving the crownwheel/diff away from the pinion and massively increase backlash. But it could be anything. I'd start by grabbing the pinion flange and trying to move it up and down - any play there means they haven't done the pinion up up correctly.

That's exactly what I'm thinking, I expect the shims are the wrong way around. It had no backlash before.

Sent it for a rebuild and reseal whilst it was off the car. It was a nightmare, they had it for 6 weeks and they constantly mucked me about. Got the work done for free in the end.

DMD transmissions in Wolverhampton. Stay well clear of them. They seem clueless.

 

[Daspete]

Just DTI'd it and I have 0.135mm so that's out by either spec.

 

[Andyboy]

Unless you know exactly what they did (new pinion bearings?) you'll need to strip it completely and start again. Later diffs (E46, E90 etc) didn't have the removable side covers, but used circlip shims to retain the side bearings.

A complete rebuild takes about a day including cleaning everything and painting the casing. I don't really do them now though.

 

[Daspete]

The shims I have don't seem to match what you can buy on original OEM either. Got a 1.94 and a 2.22mm no idea which new ones I need to buy none seem to be suitable.
Bearings seem to be done too, looks like some grit has gone round them. The seals look old too so God knows what those idiots did.

Good used one maybe the way to go if I can find one for sensible money. All I can find is high milers for £175 minimum which will just be trouble.

 

[Andyboy]

Look for an E36 Compact diff, same thing. 3.38 or 3.45 but no real difference on the road.

 

[Lee]

Not really.

The pinion height is set by the shim between the big pinion bearing and the diff case. The crush tube is there to set bearing preload, nothing else. This is set either by 'feel' (you get it after rebuilding a few) or by torque wrench until the pinion bearings have no play and the flange requires just 0.7 nm to turn without the oil seal fitted. Once set, the flange/pinion/nut are marked, the flange removed and the seal fitted.

What may have happened with this diff is that the clowns who did it fitted the output flange shims on the wrong side - this would have the effect of moving the crownwheel/diff away from the pinion and massively increase backlash. But it could be anything. I'd start by grabbing the pinion flange and trying to move it up and down - any play there means they haven't done the pinion up up correctly.

This is exactly why we've not built one, not felt like we've had enough information. On a plus side though we have a local transmission company that overhauls them for us with new bearings and seals for £150, we cant grumble at that.

 

[Daspete]

This is exactly why we've not built one, not felt like we've had enough information. On a plus side though we have a local transmission company that overhauls them for us with new bearings and seals for £150, we cant grumble at that.

That's what's worrying me. There's no real information about them only YouTube videos and forums and they're all different. I could probably tackle it using common sense but the shims are really confusing.
No idea which ones to buy.

Might give it to someone who has more knowledge, problem is finding someone. Where abouts in the country is the person you use?

 

[Lee]

That's what's worrying me. There's no real information about them only YouTube videos and forums and they're all different. I could probably tackle it using common sense but the shims are really confusing.
No idea which ones to buy.

Might give it to someone who has more knowledge, problem is finding someone. Where abouts in the country is the person you use?

We're based in Hampshire he's in a tiny unit outside of Basingstoke, he's done 5 for us so far.

 

[DannyP]

We're based in Hampshire he's in a tiny unit outside of Basingstoke, he's done 5 for us so far.

Hi Bud can you advise on details as i live in Dorset so not far and i have what i believe to be a slip diff on its way out.

 

[Lee]

Hi Bud can you advise on details as i live in Dorset so not far and i have what i believe to be a slip diff on its way out.

Feel free to contact him 'BK Transmissions' the deal we have is exclusive to the zedshed so the prices may double. He's also very busy up till new year.

 

[DannyP]

Feel free to contact him 'BK Transmissions' the deal we have is exclusive to the zedshed so the prices may double. He's also very busy up till new year.

Thanks Lee