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Sierra Diff Mounting Points
smdl - 10/7/06 at 12:14 AM

I'm wondering if the diff mounting points are different depending upon the type of Sierra diff used (7" and 7.5")?

Most cars that I see using Sierra diffs use two flat plates along the outsides of the e & f tubes and bolt to the upper and lower mounting points on the diff. This necessitates that this upper and lower mounts are in alignment.

On my diff, the lower mounting points (with the long bolt and nut) are about 7" apart, whereas the uppers are in excess of 7.5" apart. The uppers also use a bolt on either side instead of a through bolt and nut.

Has anyone used a diff like this on their car? If so, suggestions or thoughts with regard to mounting would be appreciated. Perhaps a spacer on the lower mounts?

Thanks,
Shaun

MikeRJ - 10/7/06 at 07:01 AM

quote:
Originally posted by smdl
I'm wondering if the diff mounting points are different depending upon the type of Sierra diff used (7" and 7.5"?


Yes, the larger 7.5" diff has different width mountings at top and bottom as you have discovered.

Spacing the mounting plates for the wider mounting point and using a spacer on the other would be the simplest method, just ensure that you have something substantial on the chassis to weld the plates to.

peterriley2 - 10/7/06 at 07:48 AM

id say either put a 'normal' mount on, then bend it out at the bottom, or weld on bits of 25x25 steel, and use the 7.5cm bolt for the bottom, then buy a longer bolt for the top. also as a failsafe, people attach the rear diff mountings onto the frame as well, as i dont know what diff you are using i cant help that much. any pics would be good!

smdl - 11/7/06 at 02:43 AM

Good point -- pics would help. Here is the diff:

Diff

Here are the mounts on the left side of the car:

Left Side

As you can see, the left-side mounting surfaces are not in alignment. The right side is better, bit still not exact.

Thanks to all who have commented so far.

Shaun

[Edited on 11/7/06 by smdl]