7 replies to this topic

[jeroendewil]

Hello All, 

 

I am setting up my diff preload and i am wondering which gasket thikness to take into account when compressed. 

I have gaskets GUG705567GM from minispares and they have a thickness of 15thou.

As the preload should only be 1-2thou it is quite difficult to determine the correct shim.

 

Thanks in advance

 

[absx2]

Lightly pinch up the diff housing bolts then fit a cover with the gasket and torque to 18 lb/ft , take it off and measure the thickness.

Reuse the gasket with a little sealant, never had one leak yet.

You really have to measure things as the production tolerances are all over the place

[Spider]

I do this by placing the Diff in the Gearbox Case and biasing it over to the RH Side (Flywheel end), fit up the Diff Cap, but only finger tight on the nuts, Fit up the RH Side Cover, with it's gasket, torque them up, then offer up the other Side Cover without it's Gasket, then use feeler gauges to measure the gap where the Gasket would be.

 

Then from that measured gap, subtract the Gasket thickness, then add the Pre-load and that should be the Shim Thickness.

[miniweights]

Hi, try this link

Edited by miniweights, 07 March 2023 - 06:39 AM.

[jeroendewil]

Thanks for the responses. I indeed do the same way. I have the right hand side cover fitted and i have pushed the diff so it is up against the rigth cover. I overshimmed on the left side and measured the gap between cover/diff houssing. The only thing is, i do not know what number to take into account for the gasket thickness when compressed. I found some figures that the gasket compresses 1-2 thou. So idea now is to set the gap to 14-15thou ( original gasket thickness) and use the compression of the gasket as preload on the diff bearings. I will add some permatex Nr3 but don't think the thickness of the permatex will make much difference.

[Spider]

The gasket here shouldn't compress much at all, I doubt you'd even be able to measure it. If the cover was fitted to the point where the gasket does compress, then you will have distorted the cover.

[Ethel]

That's a good argument, the covers aren't that solid. I suppose if you were really keen you could measure the difference before & after compressing the gasket on the other side  through the diff, same as you determine the preload.

[babsbrown]

Thanks for the responses. I indeed do the same way. I have the right hand side cover fitted and i have pushed the diff so it is up against the rigth cover. I overshimmed on the left side and measured the gap between cover/diff houssing. The only thing is, i do not know what number to take into account for the gasket thickness when compressed. I found some figures that the gasket compresses 1-2 thou. So idea now is to set the gap to 14-15thou ( original gasket thickness) and use the compression of the gasket as preload on the diff bearings. I will add some permatex Nr3 but don't think the thickness of the permatex will make much difference.

Just doing the job now with the same gaskets. Glad you asked this question, saved me a lot of digging.