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Hello again everyone. So after a few days of finishing my whole tensioner job my differential decided to grenade on me while driving. Luckily there was little to no cars around and I was able to pull off to the shoulder. It scared the living s!*t out of me, for a sec I had thought I had gotten rear ended. I knew this was coming since I had a faint sound coming from the diff. I already dropped the rear end and was quite surprised at how little time it took. Anyways, I'm stumped on what to do. I don't know if whether I should just buy another 14HU and swap it out. Or buy another 14HU and add the quaife QDF5W LSD to it. I'm also wondering if its possible to just buy the ring and pinion and replace that on the diff I have but have had no luck finding it. Either way I think it would be cheaper to get a used 14hu and take it off that and swap it. If I were to find a low mile 14hu, would I be able to just slap that one on and call it a day? I'm curious because JTIS stated to mark the Jurid coupling. And I got to thinking, well if I got another 14hu there would be no way in hell that it would match up with the mark. And another thing. I have not been able to find the backlash spec nor the pinion nut preload spec anywhere. I read through all 9 pages of the thread adam started about upgrading his ratios, got lots of info there but no specs.
Ill provide pics and if anyone would like more don't hesitate to ask.
Thanks in advance!
As far as rebuilding it, I wouldn't. Once the little bitty pieces have scattered, you can write it off. A replacement would be the quickest and most economical obviously, any options would be a personal touch. Try a search using... Car-Part.com--Used Auto Parts Market ...another source would be site sponsor Conventry West.. Coventry West rebuilt Jaguar Differentials ...they can supply the parts or sell you an already rebuilt one with a warranty... Coventry West rebuilt Jaguar Differentials
I'm working on that affectionate "I love you" on the spring. I don't recall that as an OE option?...lol
As far as rebuilding it, I wouldn't. Once the little bitty pieces have scattered, you can write it off. A replacement would be the quickest and most economical obviously, any options would be a personal touch. Try a search using... Car-Part.com--Used Auto Parts Market ...another source would be site sponsor Conventry West.. Coventry West rebuilt Jaguar Differentials ...they can supply the parts or sell you an already rebuilt one with a warranty... Coventry West rebuilt Jaguar Differentials
I'm working on that affectionate "I love you" on the spring. I don't recall that as an OE option?...lol
Lol! Those messages are definitly not OE. I just have a thing for leaving little messages in weird spots throughout the car haha. Just recently with the tensioner job I left another not on the inside of the timing chain cover. Anywas, just gave Coventry west a call and asked them for a quote and came out saying that, for a rebuilt diff. itll run 1800 and for a used diff. assembly itll be 250. I then asked how much more they would charge if I shipped them the quaife QDF5W lsd and have them install it in the diff. and the guy said that he was sure it can not be done. And has never heard of one being installed and that they've been doing diffs forever.
Another question. For these 14HU diffs we dont need a case spreader due to the output shafts being like a sort of spanner with threads right? Someone correct me if I'm wrong. And if anyone has the specs for the preload on those output shafts and pinion nut and backlash spec, would you mind sharing or posting a link? And Yes I have match marked the output shafts just so I know where they were originally at
Dang, I guess they want you to think they are hiding gold in their diff? I cannot find anything on lash, nor do I know of where to find it. I've read and reread posts from Bob, Avos, Plums to no avail. I did go on Coventry looking for a rebuild kit and all they had were these bearings. 2001 Jaguar XJ8/XJR 4.0 ltr V8 S/C, Bearings
Its been awhile since I ran across these folks, can't hurt to ask since they say they don't break the bank...Jaguar and Land Rover Differentials and Differential Parts
I did find on Jagbits where they had a used diff for $900, which means you can probably get one from a yard for $600.
Last edited by Highhorse; Mar 16, 2018 at 09:04 PM.
That's exactly what happens for the weak 8" 14HU. Happened for me also (+ for many others ) - even there was a Quaife. Went to stronger 8.5" 15HU.
How difficult is it to change over to the 15HU or what has to be done? Does it have the same 3.06 ratio? I do not want to deal with all the reprogramming of the tcm.
Originally Posted by Highhorse
Dang, I guess they want you to think they are hiding gold in their diff? I cannot find anything on lash, nor do I know of where to find it. I've read and reread posts from Bob, Avos, Plums to no avail. I did go on Coventry looking for a rebuild kit and all they had were these bearings. 2001 Jaguar XJ8/XJR 4.0 ltr V8 S/C, Bearings
Its been awhile since I ran across these folks, can't hurt to ask since they say they don't break the bank...Jaguar and Land Rover Differentials and Differential Parts
I did find on Jagbits where they had a used diff for $900, which means you can probably get one from a yard for $600.
Thanks so much for your help highhorse! Hopefully I find one, as well as the quaife lsd. That'd be awesome. I just can't begin to imagine how these x308's shine with an LSD.
Originally Posted by Col. Sandurz
If you still need a diff I have one or two laying around here.
May be able to bring one with me to CA in week..
Mr. Sandurz, you would make my whole year if you're able to bring one. I'm in Los Angeles.
Thanks to you all that have chimed in. I always appreciate your help!
How difficult is it to change over to the 15HU or what has to be done? Does it have the same 3.06 ratio? I do not want to deal with all the reprogramming of the tcm.
Thanks so much for your help highhorse! Hopefully I find one, as well as the quaife lsd. That'd be awesome. I just can't begin to imagine how these x308's shine with an LSD.
Mr. Sandurz, you would make my whole year if you're able to bring one. I'm in Los Angeles.
Thanks to you all that have chimed in. I always appreciate your help!
14HU/15HU gear ratios are different, so proper working requires TCU reprogramming or totally new adjustable TCU. Both ways are expensive. Shot peening of 14HU ring and pinion would give you extra strenght.
When I rebuilt the 15HU in our '93 XJ40, I couldn't find any specific information on backlash, preload, etc. In fact, I think I only found one document pertaining to Salisbury diffs, and it was for much earlier models. But piecing together various specs from Dana Spicer and Jaguar documents, some sent to me by Bob Gauff and Pete Peterson (at the Jag-Lovers forum), I used a backlash spec of 0.004-0.007 in. and a pinion bearing preload spec of 35-55 in. lbs. without the carrier installed. A Spicer manual stated that preload should increase 5-13 in. lb. with the carrier installed, so that was the spec I used when choosing carrier shims.
The large images at Jag-Lovers are still "being transitioned to a new server," but you can see my thumbnails and descriptions here:
Rebuilding a diff is no small task, and my recommendation would be to avoid it if possible, even if it means just slapping in a good used unit with fresh fluid. Dropping the IRS and swapping diffs is easy enough that you could do it again in a few years and still be far ahead in time and money.
Regarding the Jurid alignment, that is far more important with the driveshaft/propshaft than with the diff, so don't sweat that. If you've moved its alignment with the driveshaft, you may have a slight vibration when you put it all back together. If so, just move the Jurid one bolt hole at a time until it smooths out again.
P.S. Bob Gauff (Motorcarman) was very helpful to me on my first diff rebuild. In fact, for at least the past 25 years he has been incredibly generous to the Jaguar community with his expansive knowledge and experience! I'm sure if you sent him a PM he would be happy to offer advice.
If those components aren't available, I'm sure you could find a shop somewhere in the U.S. that could custom make a set for you. Of course, I assume that it would be rather expensive to do so.
I implemented the stronger 15HU differential design into the X308.
Its what should have come with the XJR in the first place.
It took a lot of design work-
I used hardened spline shafts and 'indestructible' Dana 44 internals and an adaptor to the jurid coupling that avoids 'whirl'.
The rear end ratio stays at 3.07 and no vehicle speed sensor flag up on the W5A580 trans
I used a Torsen T2R LSD. That has about 75-85% lock up ratio
(Ford performance motorsport use them on their racing Mustangs)
Its a gear design so doesn't wear like a clutch type design
Stock Jaguar 15HU uses 10 input splines and 19 output shaft splines
I got shafts designed that utlised 30 output splines and that opened up the possibility of using a high performance LSD
I implemented the stronger 15HU differential design into the X308.
Its what should have come with the XJR in the first place.
It took a lot of design work-
I used hardened spline shafts and 'indestructible' Dana 44 internals and an adaptor to the jurid coupling that avoids 'whirl'.
The rear end ratio stays at 3.07 and no vehicle speed sensor flag up on the W5A580 trans
I used a Torsen T2R LSD. That has about 75-85% lock up ratio
(Ford performance motorsport use them on their racing Mustangs)
Its a gear design so doesn't wear like a clutch type design
Stock Jaguar 15HU uses 10 input splines and 19 output shaft splines
I got shafts designed that utlised 30 output splines and that opened up the possibility of using a high performance LSD
I have spent many hours over the past couple of days researching what I need to do in order to upgrade a 14hu differential. Replacing it with a 15hu seems like the only way to go.
What all would I need to do to have a custom adapter made up. Would I need custom output splines too?
I have spent many hours over the past couple of days researching what I need to do in order to upgrade a 14hu differential. Replacing it with a 15hu seems like the only way to go.
What all would I need to do to have a custom adapter made up. Would I need custom output splines too?
that’s the big baller method. use a 19 spline carrier and you have way less drama and a heavier wallet.
if you reuse the 15hu 3.58 ring and pinion chirpy makes a can spoofer, if you don’t want to do that you need to buy a 3.06 gearset and go to the driveshaft shop.
that’s the big baller method. use a 19 spline carrier and you have way less drama and a heavier wallet.
if you reuse the 15hu 3.58 ring and pinion chirpy makes a can spoofer, if you don’t want to do that you need to buy a 3.06 gearset and go to the driveshaft shop.
I'm going to put in dana internals for 3.06. I'll see what I can come up with for making the jurid coupler work and I'll take it to a drive shaft shop as a last resort.
Differential dilema
