IRS Diff Issues

[daxtojeiro]

Hi all,
I drove my coupe for the first time last week and there's an awful noise from the rear on overrun. If I put the clutch in the noise disappears, so I am assuming its the diff. I guess I haven't got some sort of alignment issue?

As it was a second hand diff I am thinking of getting it refurbished, but the local guys prefer me to get all the parts and they will do the work on it.
I'm in the UK, so not easy to get hold of parts and no suppliers of new ones.

Does anyone have any recommendations as to suppliers of the parts and an idea of what I would need, I have found these so far, but not 100% certain it is everything or if they are right:

https://performanceparts.ford.com/part/M-4210-B3

https://performanceparts.ford.com/part/M-4204-M

https://performanceparts.ford.com/part/M-4209-88355A

thanks for any help
Phil

[Gordon Levy]

Offhand I would say the gear mesh pattern is not correct.

[daxtojeiro]

Hi Gordon

thanks for the reply, Im not sure what you mean, do you think I have aligned something wrong?

Its a new TKX gearbox and a 347 stroker engine if that makes any difference.

thanks
Phil

[Skuzzy]

Hi Gordon

thanks for the reply, Im not sure what you mean, do you think I have aligned something wrong?

Its a new TKX gearbox and a 347 stroker engine if that makes any difference.

thanks
Phil

He is talking about the alignment between the ring and pinion gear in the differential.

[ggunter]

The back lash between the ring and pinion will make a rear whine. Too loose or too tight will make it talk. A bad bearing in the carrier will usually make a roaring sound along with the whine. Ring and pinion sets are mated on a honed on a machine to form a running surface that needs to be replicated when setting up the rear running clearances. This is done by changing the clearance of the carrier to the pinion or the pinion depth to get a running pattern. On the internet you can look up carrier to pinion patterns. That's why they put a paint on the ring gear and rotate it to show the pattern.

[daxtojeiro]

Thanks for that. So I need to replace the carrier and pinion, or can it be adjusted?

I guess it may as well be overhauled or is that pointless?

thanks
Phil

[edwardb]

Assuming it's the internals of the diff (sounds like it) no way to really know exactly what's wrong or needs to be rebuilt/replaced until it's pulled apart. The gear mesh is adjusted with shims. Those rings in the ring and pinion installation kit. But that's assuming nothing else is wrong.