Hello there
I removed the non-original rear axle from our XK120.
It seems to be a Salisbury 4HA and the number on the differential is L55 8275.
I would like to sell it, but I have no idea from which year or model it is.
Could someone help me?
Thank you very much in advance and best Regards
Lukas
What does the ratio tag on the back cover say? I can make out the 13 which is the pinion teeth, but not the other number which is the crown teeth count.
L55 might mean November 1955.
not that non-original late xK120’s had 4HA’s!
will only be missing two tabs for lever arms these can be welded on
The fact that it is missing those tabs but has the same brake setup and wire hubs and dating from 1955 suggests that it could be for a 140.
Thank you very much Rob and Terry for your thoughts and your help 
I had a closer look this morning, the ratio tag shows 46-13 it’s therefore a 3.53 differential and the axle most probably out of a XK140.
Best Regards
Lukas
Learning from “you guys”
Would this likely be an open or limited slip?
And what ratio is preferred with the 120, 140 even the 150
Mitch
Regular diff, not limited slip; those came along as an option in the XK150 era.
The 3.54 is the standard ratio, for general driving.
I have the ENV 3.64, which I find is just fine for suburbs and highway. I don’t do hill climbs, no mountains here, and never get over 80 mph, too much traffic in my part of the world.
Rob,
Thank you
Mitch
3.54 became standard with the later 120s…thru the rest except for overdrive cars. As to “preferred” I like the ratios in the 3.09 to 3.27, 3.31…some could be from new as installed at the factory, and many ratios less than 3.54 were available as it is basically a Dana 44, made by Leys in England. You can use the 600-16 tire diameter of about 28 inches…or whatever tire you may use, with the many on web calculators to play with diff ratio and what rpm it will give at what mph. The Jag manual and owners guide have charts for several, 3.77 and 3.54 for the later cars.
With a 3.54 you can change to the 3.31 etc but cannot go to 3.77 or more…due to different carrier parts. For Lukas…the tag is a clue…but of course the diff ratio could have been changed at some point…to absolutely know you either have to rotate and count wheel or hub turns to drive shaft turns.or remove the cover and look for the markings on the gear. .Nick
I have just put a 2.88 powerlocker in mine with 16 inch steel wheels.
Will be interesting to see what it is like. Should get it going soon.
I have the same ratio in an E type and it it is my favorite.
Turn one brake drum by hand. If the opposite side rotates the same way it is Power Lok. If the opposite side rotates the opposite way it is a standard open diff.
but the E has 15 inch wheels/tires , while 16 in on the XK, and that makes quite a bit of revs difference. Possibly 26.5 diam on the E, and 27.9 on the XK…you can plug that into the web calculators to find rpm at mph. Nick