Sorry to be ignorant but can someone please explain the difference between these differentials?
TIA
Frankie
Similar but different. Assemblies will interchange, but lots of individual parts differences. Salisbury seem to be preferred, but in the US, Dana 44s are used in a lot of applications (Corvettes, Jeeps, trucks). Main difference is in the caliper mounts and output shaft bearing retainers…internals are different also, but Dana gearsets can be used with custom bearings and ring gear bolts.
Drain plug on bottom of the differential case indicates Salisbury, as does the one piece caliper mount/output bearing retainer held in place by 5 bolts. Salisbury is by far more common.
Thanks Robert. The reason I ask is because I have the opportunity to buy a Dana Powerlok diff from a V12 XJS to swap into the cage of my 1971 XJ6 (fitted with its original Salisbury diff). I’m trying to find out if it’s a straight swap. From what you say the caliper mountings may be an issue? If the Dana PL won’t swap straight into the cage the Dana crown wheel and pinion set will need some custom modification to fit into the Salisbury (open diff) casing? The purpose of the project is to change the gear ratio.
Frankie
Based on my XJ-S experience-
Most if not all Dana XJ-S differentials are 2.88 ratio…and are usually a little noisey.
Assemblies mount to cage the same. Output flanges and axles are dimensionally the same. Calipers are the same; only the brackets and rotors differ. Rotors are different to allow access to the caliper bolts on the Dana (they go in from the opposite direction). Driveshaft companion flange is round on Salisbury and square on Dana, but driveshaft bolts in the same way. In other words, on the XJ-S, you can remove a complete Dana and install a Salisbury into the cage with no other parts. If you remove a Salisbury to install a Dana, you need the correct rotors.
The XJ-S uses a differential mounted speedo transducer from mid '88; if your '71 is transmission mounted, or speedo is cable driven, you will need to correct the drive ratio for the speedo to be accurate with a different axle ratio. The differential-mounted sensor isn’t affected by the axle ratio, but the signal is not compatible with the trans sensor speedo. There may be adapters to correct the signal.
You can install the Dana internals into the Salisbury differential case with special bearings, but that requires setting up the gear mesh identical to its original state to prevent noise…
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Well, perhaps this needs clarification. In the early XJ-S, the diff was made by Salisbury. Around 1987 or so, something went belly-up at Salisbury, so Jaguar switched to using diffs made by Dana. In the meantime, Salisbury was bought out by Dana, and a couple of years later resumed making diffs for Jaguars in the original Salisbury design. We have, by convention, taken to calling these diffs “Salisburys” even though they are actually made by Dana. What we call a Dana diff is the one with no drain plug and the output shafts retained with 3 bolts instead of 5, only fitted to the XJ-S for a couple of years in the late 1980’s.
The innards are similar but different. They both work well enough, but rebuilders complain about the difficulty of getting parts for the Dana. So when a Dana needs rebuilding, it’s common practice to just go ahead and replace it with a Salisbury.
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I’m beginning to off the idea of a Dana. The problem (in the UK anyway) is that 2.88 Salisburys are hard to come by. New crown wheel and pinion sets are available (at a price) but then there is the cost of fitting and setting them up (which is beyond my skill). What I really wanted was a second hand cage complete with a 2.88 Salisbury so I had the option to swap back to my original 3.31 set up relatively easily if I wanted.
Maybe I need to be more patient!!
Thanks Kirbert and Robert.
Frankie
My 84 UK XJ12 had a 2.88 Dana but that only lasted a comparatively brief time. The default was Salisbury and V12s were all Powr-Lok. The US never got the Series 3 V12 XJ but the UK did, so it is easier in the UK than USA.
In effect, when searching you could assume every UK XJS V-12 and every post-79 XJ12 you come across being dismantled had a 2.88 LSD. Then just phone to rule out the ones with no drain plug.
You can convert a Salisbury to 2.88 but you need a different LSD carrier to suit the ring gear. I’ve got one but shipping might be a nuisance even for the bare carrier.
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Thanks Peter - that’s very helpful. Its not urgent but I would like to complete the project sometime next year. I will continue to search the ads.
Frankie