Thread: diff ratio

4.1 ratio is geared for 35" tyres (generally). The gearing will be too low for standard tyres. Good for crawling but it will rev its guts out at highway speed. In the 2002 you should have the salisbury rear end. It is plenty strong enough for a locker and axle upgrade.

cheers MLD

The standard ratio is 3.54, so you will need both front and rear done at the same time. 4.11 ratio will make the engine rev more at lower speeds so you can fit larger tyres and still have the same performance.
Also is your rear diff a salisbury or a p38/rover type, I have an 02 def and it is a salisbury but others i've seen/spoken to from same year have the rover rear diff. Check as they dont mix. I fitted a detroit to my sal's with hy-tuff axles, the ashcroft unit looks good though.

my diff is a rover diff maybe ill just fit the dill lock with out the upgrade axles already been upgraded back to the drawing board!!!

Originally Posted by hans

my diff is a rover diff maybe ill just fit the dill lock with out the upgrade axles already been upgraded back to the drawing board!!!

Have another look mate because it want be a rover diff in the rear. From that comment, it must be a P38 diff. The Sals has a tin cover plate on the rear that has multiple bolts holding it on. The P38 diff looks very similar to the front diff.

i did sent photos of my diff to ashcrofts and they assured me that its a rover diff , now you got me worried and thinking what i have got
thanks

Hans, Going back to your original query about upgrading the C&P. Whether the salisbury or P38 or Rover diff I think you will find the 3.54 OEM C&W more than adequate to cope with a locker upgrade. There are fellas running around on lockers and 35" tyres with the OEM 3.54 diff. That assumes you are not planning to build a comp truck.

Ask Ashcroft if their C&W pegging system is a better option to bind it all together to avoid mashed teeth. Their web site says it's only available 'in house' but there may be an exception if they have a suitably qualified Oz distributor who is prepared to do it.

cheers MLD

4.11s are alleged to be a little stronger than 3.54s.

And be careful, there are 4.10s and 4.11s out there. In days gone by I bought a 4.11 and it was a 4.10 that was delivered. A mismatch front to rear for quite a while, & numerous breakages later this was discovered.

If doing it again I'd count the teeth myself before installation.

Regards
Max P

Hans, dont worry, there has been much use of the wrong termanology/name for your rear diff. It is often reffered to as the Rover or Puma diff, and that is the problem.

NO LR had them in the front, AND they were about well before the PUMA. There are 3 basic types of diff.

Rover Type: which in coil sprung aplication was used on the original Range Rover (or Range Rover Classic as they now have become) front and rear, up until the introduction of the P38 Range Rover, it was used front and rear on ALL 90's (still is), the front of all 110,127 and 130's (still is)and front and rear of Disco 1, and Im pretty sure Disco 2 (Disco 2 have different housings, link set up, open knuckles and semi floating axles)

The rear of the 110, 127 and 130 are where it changes. Originally and up to about 2002 these vehicles had the Sals 8HA, which is the pommy version of a Dana 60....BIG cast iron center with pressed in axle tubes, much larger than the rover type. It is also low pinion, that is the propshaft joins low to the diff pinion rather than the center like the Rover type. In about 2002 Rover (in there infinet wisdom) changed the Sals 8HA for the P38 type rear diff on these 110, and 130's (127 having been now superseeded by the 130)

Im betting yours is the P38 type rear diff. If it looks similar but not identical to the front (Rover) diff, it is. If your rear diff is twice the size and ALL cast iron for the center section it is a Sals.

Again I suspect you have the P38 type. It has 2 main problems (well 3) #1 its Ring gear is very thin. #2 its pinon is very short with little bearing seperation, but most importantly #3 is they now seem to be being set up very poorly in the factory...

If you have had no problems with yours and you want to use stock size tyres IMO I would just get the ashcroft locker and run it...maiking sure the diff/back lash is set up by a diff specialist!

If it is a P38 type, you only have 2 options for R+P, that is stock and Ashcroft 4.1, which means changing both front and rear R+P.....