Hello,
Looking for some insight on a diff for sale locally.
First is $300 a deal?
Secondly, is there a way to test any possible issues?
Lastly, is this something worth my time? I was going to completely rebuild my IRS. Is it worth swaping out the one I have now (1975 XJC).
A 2.88 PowerLock, almost certainly out of an XJS V12 or Series III sedan V12
The 2.88 ratio is common. The Powerlock somewhat hard to find
Your car likely has a 3.31 ratio. Going to a 2.88 is quite a dramatic change. You might like it, or maybe not. I went the other way in my car, from a 2.88 to a 3.31
I would assume the unit needs overhaul
Cheers
DD
First question would be what is the state of the diff in your car?
The Power Lock is a nice feature, the longer ratio a personal choice (I like it personally but I have a V12).
If you are going to completely rebuild your IRS you should rebuild either diff regardless, i.e. new seals and bearings, so workwise would be the same thing.
Nevertheless, the 2.88 is an unknown quantity as you don’t know what’s happening inside.
As nice as a PowrLok diff is as a feature, 2.88 seems way too long for a stock auto 6 cylinder car. While it may be perfect for cruising at 75-85 mph, it will make the standard car quite sluggish, in particular if it is the US SII with 1.75 " Stromberg carbs.
Combined with a manual gearbox or with a beefed up engine (at least twin HS8 or FI) it might work out well.
Good luck
Jochen
75 XJ6L 4.2 auto (UK spec)
the ratio change is key
do you want it
what is your present ratio
do you do much long distance cruising or prefer acceleration off the line ?
$300 is about right, if its ok
