Diff from a 948

[Alessandro]

Hi everybody I am currently replacing my rear axle on my 1098 and I have picked up a 948 from a 62 car I will be putting my 1098 diff in the casing I know about filling the axle which is no problem because I can use the breather but what I want to know is what ratio is the 948 diff the only markings I can find on the diff are inside and it says ATA7034U I was kind of hoping it could be a 3.7 diff but I doubt it cheers.

[chrisryder]

if you have the diff out of the axle, you should be able to read a code on the outside edge of the crownwheel gear.

It will be given as a fraction such as 9/38, which would equate to 9 teeth on the pinion and 38 on the crownwheel. In that case, your ratio is 4.22:1 (standard for a 1098 minor).

If it's standard 948 the ratio would be 4.55:1.

[Alessandro]

if you have the diff out of the axle, you should be able to read a code on the outside edge of the crownwheel gear.

It will be given as a fraction such as 9/38, which would equate to 9 teeth on the pinion and 38 on the crownwheel. In that case, your ratio is 4.22:1 (standard for a 1098 minor).

If it's standard 948 the ratio would be 4.55:1.

I will have a look thanks for that

[chrisryder]

Just to clarify, the red line is the sort of place you'd find the marking. You may have to turn the gears by hand to rotate it around to the right bit.
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[mike.perry]

Unless you want good acceleration and revving the nuts off at speed then put the 1098 (4.22) diff back in. There is a chart of gearbox and diff applications on http://seriesmm.mmoc.org.uk Car Ident. Gearbox and Rear Axle Ratios

[Alessandro]

Hi I have checked the diff today and it is the 948 one so I have fitted the 1098 back in thanks for eveybodys help