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rear axle 2.8:1
Posted: Tue Jul 05, 2011 6:51 pm
by truckdoctor
Where can i get a rear axle with a width of 60 inches wheel mounting face to wheel face with a diff ratio of between 2.8:1 and 3.0;1?
Have been told MOPAR stuff from the 70's is suitable but apear to be like hens teeth, so I'm wondering if there is a modern axle available that not to expensive as I'm on a budget.
Thanks
Posted: Wed Jul 06, 2011 9:15 am
by kiwicar
hi
Ford 8.8" will do 3.08:1 rear ratio, get a case and shafts cut to the size you want would do it. Ford 9" goes lower but is alot more money and compleet overkill for most aplications, GM 10 and 12 bolt don't seem to go quite that low.
I seem to remember a relient scimiter axel case will take Jaguar (indipendent suspension) diff components with a little modification, if that is so then there are Jag ratios go down to 2.88, I am sure someone knows this one for certain and what will fit and how.
Best regards
Mike
Re: rear axle 2.8:1
Posted: Wed Jul 06, 2011 11:53 am
by CastleMGBV8
truckdoctor wrote:Where can i get a rear axle with a width of 60 inches wheel mounting face to wheel face with a diff ratio of between 2.8:1 and 3.0;1?
Have been told MOPAR stuff from the 70's is suitable but apear to be like hens teeth, so I'm wondering if there is a modern axle available that not to expensive as I'm on a budget.
Thanks
60" is actually quite wide, so what it going into and what sort of power are you going to put through it?
An SD1 axle from an automatic will be 2.84/1 not sure the exact width but someone will know on here.
Kevin
Posted: Wed Jul 06, 2011 12:28 pm
by kiwicar
Hi
as a thought Merc sprinter perhaps? deisel, revs to about 4.5k flat out and they will do well over 100mph, must be geared fairley high, and they are pretty wide. you can get them with a limited slip diff as an option aswell!
Best regards
Mike
Re: rear axle 2.8:1
Posted: Wed Jul 06, 2011 12:43 pm
by DaveEFI
CastleMGBV8 wrote:truckdoctor wrote:Where can i get a rear axle with a width of 60 inches wheel mounting face to wheel face with a diff ratio of between 2.8:1 and 3.0;1?
Have been told MOPAR stuff from the 70's is suitable but apear to be like hens teeth, so I'm wondering if there is a modern axle available that not to expensive as I'm on a budget.
Thanks
60" is actually quite wide, so what it going into and what sort of power are you going to put through it?
An SD1 axle from an automatic will be 2.84/1 not sure the exact width but someone will know on here.
Kevin
The SD1 2.84 was only used on injection autos (Vitesse, EFI) so is quite rare and correspondingly expensive. An SD1 club memeber has one of offer for £100. He's SW London(ish) area. But it's not me.

Re: rear axle 2.8:1
Posted: Wed Jul 06, 2011 3:15 pm
by truckdoctor
CastleMGBV8 wrote:truckdoctor wrote:Where can i get a rear axle with a width of 60 inches wheel mounting face to wheel face with a diff ratio of between 2.8:1 and 3.0;1?
Have been told MOPAR stuff from the 70's is suitable but apear to be like hens teeth, so I'm wondering if there is a modern axle available that not to expensive as I'm on a budget.
Thanks
60" is actually quite wide, so what it going into and what sort of power are you going to put through it?
An SD1 axle from an automatic will be 2.84/1 not sure the exact width but someone will know on here.
Kevin
It's for rover p5b coupe 3 speed low power v8 at the moment but will upgrade soon. It's to help with MPG figures also The sd1 sound interesting
Posted: Wed Jul 06, 2011 11:19 pm
by CastleMGBV8
Truckdoctor,
Name?
Check what your existing axle is, if it's a Salisbury you may be able to get a higher ratio crownwheel and pinion. Would save a lot of fabrication with spring and damper mounts etc.
Kevin.
Posted: Thu Jul 07, 2011 4:02 pm
by harvey
CastleMGBV8 wrote:Check what your existing axle is, if it's a Salisbury you may be able to get a higher ratio crownwheel and pinion. Would save a lot of fabrication with spring and damper mounts etc.
It's a banjo axle, and although there are various ratios as the diff unit is shared with the Rover 3 litre, and the Land/Range Rover, AFAIK the highest ratio is 3.54 which is the one he thinks he has got already. His further check on the ratio may enlighten us a bit more on that though. The SD1 axle would be a good choice as it shares the same stud pattern, but would still need modifying to fit leaf springs, and it has a very long pinion housing which would give propshaft problems as well.
Posted: Thu Jul 07, 2011 5:30 pm
by DaveEFI
If you remove the extension tube on the SDI, the pinion shaft has a thread on the end which serves no purpose. So it might be possible to find the bits to convert the SD1 axle to work without the extension? No idea from what vehicle, though.
axle
Posted: Thu Jul 07, 2011 8:01 pm
by truckdoctor
CastleMGBV8 wrote:Truckdoctor,
Name?
Check what your existing axle is, if it's a Salisbury you may be able to get a higher ratio crownwheel and pinion. Would save a lot of fabrication with spring and damper mounts etc.
Kevin.
Had a measure up today, 59 3/4 inches between the wheel mounting faces. 3.5:1 ratio diff
Very interested in the sd1 axle, any one have a few dimensions please?
STEVE
Posted: Fri Jul 08, 2011 1:52 pm
by harvey
DaveEFI wrote:If you remove the extension tube on the SDI, the pinion shaft has a thread on the end which serves no purpose. So it might be possible to find the bits to convert the SD1 axle to work without the extension? No idea from what vehicle, though.
ISTR that axle was modified and used in the TR8 without the pinion extension so that may be a way to find parts to do the same thing to an SD1 axle.
Posted: Fri Jul 08, 2011 2:10 pm
by DaveEFI
harvey wrote:DaveEFI wrote:If you remove the extension tube on the SDI, the pinion shaft has a thread on the end which serves no purpose. So it might be possible to find the bits to convert the SD1 axle to work without the extension? No idea from what vehicle, though.
ISTR that axle was modified and used in the TR8 without the pinion extension so that may be a way to find parts to do the same thing to an SD1 axle.
Another mystery solved, thanks.

Posted: Fri Jul 08, 2011 2:11 pm
by CastleMGBV8
I believe you can swap the nosepiece for the shorterTR7/8 version.
Kevin.
Posted: Mon Jul 11, 2011 7:06 am
by minorv8
I am running a shortened TR 7 axle in my Morris with SD1 3,08 ratio. The diff is identical in TR7/8 and SD1, except for the ratio of course. So, you can take the SD1 axle, discard the extension and use a TR7/8 propshaft flange and alloy nose piece. The latter is NLA as new so you may need to find a used TR7 to rob the parts.
Note also that you need parts from 5-speed TR7, the earlier 4-speeds had Marina type axles.
axle width
Posted: Mon Jul 11, 2011 8:57 pm
by truckdoctor
located the width of an sdi and its 62 inches between wheel mounting faces which is OK but the lowest ratio as far as I can find out is 3.09.
Not sure if 2.7 is available though . Is this correct?