I’m trying to determine what type of diff I have. Apparently early 2.4 models carried the 3Ha. But hoping i have 4Ha…
The question being. Does anyone know of any visual cues to confirm the difference between 3Ha & 4Ha.
I’ve just rebuilt my MK2 2.4 rear axle which is from a 1967 and is a 4HA, the rear plate on mine looks the same as yours. Mine had the reference in the casing to the left of the cover in your picture above, you can just see it in the picture below.
Mine, Mk1 3.4 of 58, also has a 4HA marking on the cast back by the cover, on opposite end, a bit off axle axis.
I presume you are in the USA or abroad
3 HA diffs were used up to 125693 chassis numbers LHD or 103507 RHD overdrive
Take off the diff cover It is a good idea anyway to clean out the casing.
The ratio is stamped on the crown wheel on the section( just under the dial gauge in Homers reply)
Just rotate slowly and you will see it
faintly etched and will have 47x11( equals 4.27 ratio)or 50x11 (equals 4.55 ratio)
Also on the crown wheel will be 4HA or 3HA
If your model is a late one chances are it will be a 4HA
On the casting around the pinion, you should find a date stamp also
If you take off the diff cover you will be able to see the condition of the gearing.
Hope this helps?
Thanks all for the info, seems 3HA were very very early models only! that’s a relief!
I’m actually based in Australia so RHD Auto 1962 4.27:1 confirmed with rotations,
is sitting in warehouse currently but want to move on this project in a few months time… . currently working on my triumph spitfire…
I’m keen to keep the ratio due to the power train I’ll install, but will have heaps of extra torque so want to upgrade to LSD.
My current thinking is the Blackline 4HA out of the UK, some what cheaper than the Quaife offering and seems comparable ???.
Anyone else done this mod? any comments?
The lowest ratio" POWR LOK" I have seen is from a overdrive model 3.8 saloon and that was
a ratio of 3.77 which is a lot hgher than a 2.4 ratio
These should be available from a good Jag breaker but are becoming scarce
I have used 3.77, 3.54 ,3.31 and 3.07 all from mark2, stype, mark 10 and early XJ6
If you are anywhere near Sydney I have used a Jaguar Race Prep Company who race at
Bathhurst Tony Pallas Orchard Road Brookvale NSW I have worked on Jags in Oz but live in UK