Thread: Help needed - Diff Set Up

at the end of the day...

if its all brand new parts you will set it up to where ever the pinion turns at the right amount of torque and the tooth bluing looks perfect.

the stock height blocks + the pinion height numbers + the funny formula give you your start point.


if this is your first go Im going to go with.... you will make a dozen attempts at setting the wheel lash and 4 attempts on the pinion height before your happy.

I still cant get to "yep, perfect" with less than 2 for the pinion and 4 for the lash.


I have the tools buried away somewhere for doing it if no-one else wants to lend them to you but postage from katherines pricey and slow.

if you have your own blocks made when you do the diff, make sure to do them up as a how to thread. dont be scared to include all the times you got it wrong as well... its easier for people to follow your methods if you show them what going wrong looks like on the bluing.

best of luck and dont be scared of it... the scariest part of putting in a locker is doing the holes and plumbing the air.

I thought your Dad would have the knowledge, Will.

Originally Posted by Blknight.aus

at the end of the day...

if its all brand new parts you will set it up to where ever the pinion turns at the right amount of torque and the tooth bluing looks perfect.

the stock height blocks + the pinion height numbers + the funny formula give you your start point.


if this is your first go Im going to go with.... you will make a dozen attempts at setting the wheel lash and 4 attempts on the pinion height before your happy.

I still cant get to "yep, perfect" with less than 2 for the pinion and 4 for the lash.


I have the tools buried away somewhere for doing it if no-one else wants to lend them to you but postage from katherines pricey and slow.

if you have your own blocks made when you do the diff, make sure to do them up as a how to thread. dont be scared to include all the times you got it wrong as well... its easier for people to follow your methods if you show them what going wrong looks like on the bluing.

best of luck and dont be scared of it... the scariest part of putting in a locker is doing the holes and plumbing the air.

Thanks Dave,

Looking at the parts catalogue for doing it, I believe I need the dogbone (LRT-51-018/7) and the setting block for the pinion head (LRT-51-018/11). I'm sure I could do away with the pinion head settting block if I just use a machined block on top of the pinion, but I still need to make a dogbone.

Both these are within my capability to make with our lathe and mill.

It would be a great help if you could post up some photos of the tooling you have, including critical measurements if that's not too much trouble

Though with brand new gears I believe I should just be able to stick a shim in (maybe even the original) and check the bluing and backlash and use a trial and error method... (is this correct?).

Thankfully there is no plumbing or drilling to do!

Originally Posted by p38arover

I thought your Dad would have the knowledge, Will.

Unfortunately he's never done a Rover diff, he's only set up Veteran diffs, which are not nearly as accurate in the set-up...

I've even asked a few mechanics that are ex Garthon's or others I know, and they all send them to diff specialists!

Originally Posted by MR LR

Unfortunately he's never done a Rover diff, he's only set up Veteran diffs, which are not nearly as accurate in the set-up...

thats got to be the only time I've ever seen a rover diff hinted at being accurate....


I'll have a dig and see whats where at some point.

I've seen pics of exactly what your asking for online, it'll probably be quicker and easier to search it up and compare the numbers to whats in the rave or online to get what your chasing, but I'll try to have a dig next week or so.

Originally Posted by Blknight.aus

thats got to be the only time I've ever seen a rover diff hinted at being accurate....


I'll have a dig and see whats where at some point.

I've seen pics of exactly what your asking for online, it'll probably be quicker and easier to search it up and compare the numbers to whats in the rave or online to get what your chasing, but I'll try to have a dig next week or so.

Hahaha... anything is accurate compared to Veteran stuff!

The bottom of this page shows the dog bone, and what I believe to be the pinion spacer for the P38a type diff... measurements of the dog bone would be lovely, as in the depth of the cut into it. Other tools Page 1

I've just had another look at the R&P's

One of them has the number 617 and 76.10 on it, the other 217H and 76.10 on it. I'm assuming that the 76.10 refers to the pinion height... in mm. Will check this with GBR Bill.

My advice is to find a diff setup mob that doesn't charge $800/hour, I'm a mechanic and I always sent my diff's (to be setup) to a mob in Silverwater, Sydney and I never paid more than a $100.
It really isn't hard to setup your crown wheel and pinion, but I don't have the patience or the tools to bother with it.
You need to set the pre-load on the pinion first, once that is to specs adjust the CW carrier to get the proper mesh of the CW&P.
There should be workshop manuals online (Google) that will show you how, Regards Frank.

Originally Posted by MR LR

Hi all,

I have purchased a set of Ashcroft ATB's and GBR 3.90 diff ratios for my Disco 2, including Timken bearings, shims, seals etc.

It is time to set them up, something I would like to do myself, to learn the skill and also save the $800 labour fee that diff specialists want to do the job...

I have read the section in Rave, trawled Youtube and the internet, TGO, tech chat, and everywhere else i can think of on Aulro.

So far Rave has given me the most information...

Has anyone else got any good resources? Experience to share? Things to look out for?

Or alternatively... does anyone who has done this before (in sydney) want to help/teach, with beer/cash reciprocation

The set up jigs are probably the hard part... I think I will need to make them (would also like the opportunity to borrow these for cash/beer reciprocation if anyone has any).

Once I have got them apart I figure it will become fairly apparent how they go back together... but with 3k worth of parts to potentially ruin, you can never be too sure.

Big question is, with new gears, is factory pinion height the go-to? (74.390mm)

Thanks in advance...

I've done this with a Suzuki and Detroit, it's pretty straight forward but I haven't done pinion height.

Before you strip it, feel with your hand the lash (Crown wheel adjustment), and you will pretty much get it again when you reassemble. It'll save a lot of mucking around. The ol' "feeler" gauge.

Hi,

I've got spare F&R diffs with Maxi axles and lockers that I want to put in my 74. Rear diff is in bits, needs new bearings and has never had the supplied R&P installed after the previous owner blew the originals.

In the same boat as the OP, and have searched around for good info for possible DIY.

There used to be an excellent video on Ashcrofts site that showed all in an ideal factory environment. Can't find it now.

And there is this article:

http://www.pirate4x4.com/tech/billavista/Gear_Setup/

cheers, DL