9/38 or 9/41 differnetial units

[RussLCV]

What's the main difference in these 2 units please

Ideally I want a 3.7 or 3.9 to use with a 1275, have one in pick up, but need a another. but at present my only choice is as above the 9/38 I assume is the best choice.

I have 2 diffs 9/41 that I am about to scrap

[ManyMinors]

The 9/38 differential is the 4.22 as fitted as standard to the 1098cc car models. The 9/41 is the 4.55 which was fitted to the 948cc cars as well as the 1098cc van I believe. Therefore the 4.22 or 9/38 will give you slightly higher overall gearing and is closer to what you hope to achieve.

I found a 3.7:1 differential made my 1275cc Minor too high geared with 14" wheels fitted with 165/80/14 tyres and felt that a 3.9:1 would have been better but it all depends on many factors - the wheel & tyre size and of course the type of driving you propose doing.

[RussLCV]

Using 165 80 14 on 4.5Js

So many thanks for your reply

Are these units easy to over haul?

[philthehill]

They can be overhauled but the problem is with the setting up of the relationship between crown-wheel and pinion.
If not set completely and absolutely right the crown wheel and pinion will in all probability whine like hell.
The 4.22 and 4.55 diffs are so cheap and easy to replace I would advise that you find a good S/H unit of either ratio and fit to your axle.

[RussLCV]

Many thanks Phil.

I do have 2 x 9/41 if anyone needs one