Question about X305 (XJ12) differential interchange
#1
#2
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Location: Pacific Northwest USA
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#3
Limited Slip Diffs have a BLACK X through the ratio color code sticker.
3.58:1 will have a red and yellow stripe sticker. If the sticker has a BLACK X across it, that will be a limited slip.
JEPC has the info
Blue=4.09
Blue Black X=LSD
Brown=3.77
Brown Black X=LSD
Orange=3.27
Orange Black X=LSD
Red/Yellow=3.58
Red/Yellow Black X=LSD
bob
3.58:1 will have a red and yellow stripe sticker. If the sticker has a BLACK X across it, that will be a limited slip.
JEPC has the info
Blue=4.09
Blue Black X=LSD
Brown=3.77
Brown Black X=LSD
Orange=3.27
Orange Black X=LSD
Red/Yellow=3.58
Red/Yellow Black X=LSD
bob
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#4
My Vehicle Care manual states the diff ratio is 3.54:1 for all X300 types. ? An inconsequential difference anyhow. The limited slip (referred to as "Powr-Loc" in the manual) apparently was an option on the XJ12, but who knows if it was available for USA models?
You finally got her running smooth, and now a diff problem? What are your symptoms?
You finally got her running smooth, and now a diff problem? What are your symptoms?
#5
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Location: Pacific Northwest USA
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I've seen 3.54 mentioned as well but more often 3.58 is quoted
The XJR/6 came with 3.27 gears.
XJ6 4.0 and XJ12 came with 3.58
XJ6 3.2 came with 3.77 or 4.09...if my memory serves
The limited slip (referred to as "Powr-Loc" in the manual) apparently was an option on the XJ12, but who knows if it was available for USA models?
The consensus is that it was not offered in USA V12 X300 cars, which is supported by my sales brochures.
Cheers
DD
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SleekJag12 (05-24-2016),
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#6
Was LSD offered on US models as an option?
The diff is Salisbury 14HU, right? I seem to remember reading that Ring and Pinion are the same as one of the Dana Spicer units, but I can't find that link now.
I am thinking about buying a spare diff, rebuilding it and taking it to a professional to check out that I ajdusted it right.
Last edited by juha_teuvonnen; 05-23-2016 at 09:36 PM.
#7
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Noise coming back from the rear end, louder at low speed. I also feel the vibration transferred onto the handbrake lever which makes me think that the rear hub bearings could be shot as well. The shop told me that the car needs a diff, and the guy at the shop knows these cars well. I'll get the car running on the lift and listen with mechanic's stethoscope, but I am very sure it's the diff. May be both, diff and bearings, though.
These cars have a bit of an appetite for diffs and wheel bearings. I had to replace the diff on my XJR/6 at just 75k miles and over the course of the years replaced rear wheel/hub bearings as well
Was LSD offered on US models as an option?
The diff is Salisbury 14HU, right? I seem to remember reading that Ring and Pinion are the same as one of the Dana Spicer units, but I can't find that link now.
The old style (inboard brake type) differentials were a kissin' cousin to the Dana 44 and some have used Dana gears. Not sure about the later differentials
Cheers
DD
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juha_teuvonnen (05-24-2016)
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#8
BUT, the pinion has a different spline count requiring
a special order companion flange, AND, the ring gear
holes are often/usually 3/8" versus 7/16".
Search for posts by ICSAmerica.
It is not likely that the gears themselves need replacement
unless they suffered from lack of lubrication. I would suspect
bearings or loss of preload first.
Loss of preload would be the cheapest to repair.
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juha_teuvonnen (05-24-2016)
#9
Dana 44.
BUT, the pinion has a different spline count requiring
a special order companion flange, AND, the ring gear
holes are often/usually 3/8" versus 7/16".
Search for posts by ICSAmerica.
It is not likely that the gears themselves need replacement
unless they suffered from lack of lubrication. I would suspect
bearings or loss of preload first.
Loss of preload would be the cheapest to repair.
BUT, the pinion has a different spline count requiring
a special order companion flange, AND, the ring gear
holes are often/usually 3/8" versus 7/16".
Search for posts by ICSAmerica.
It is not likely that the gears themselves need replacement
unless they suffered from lack of lubrication. I would suspect
bearings or loss of preload first.
Loss of preload would be the cheapest to repair.
#10
Limited Slip Diffs have a BLACK X through the ratio color code sticker.
3.58:1 will have a red and yellow stripe sticker. If the sticker has a BLACK X across it, that will be a limited slip.
JEPC has the info
Blue=4.09
Blue Black X=LSD
Brown=3.77
Brown Black X=LSD
Orange=3.27
Orange Black X=LSD
Red/Yellow=3.58
Red/Yellow Black X=LSD
bob
3.58:1 will have a red and yellow stripe sticker. If the sticker has a BLACK X across it, that will be a limited slip.
JEPC has the info
Blue=4.09
Blue Black X=LSD
Brown=3.77
Brown Black X=LSD
Orange=3.27
Orange Black X=LSD
Red/Yellow=3.58
Red/Yellow Black X=LSD
bob
I have a 2.88 out of an '85 xj12 and it has a green with black X
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