Hi guys

Not sure if this is in the right place so apologies if it isn't.

I am currently running a 3.62 Cossie LSD, which is way too short for my liking. I am after a 3.38 or 3.14 (I know, I know)... I understand that I can swap the internals about if I find an open diff of the correct ratio, could someone confirm this is correct? I have access to a machine shop if any work of this type is required.

I'm assuming that 7.5" internals (CWP) will not fit into a 7" diff?

Anyone have any suggestions/ideas or anything to sell that will help?

Cheers

Max

All 7" diff CWPs are interchangable.

I am part way converting to a 3.92 LSD.

Basically find an open diff in your chosen ratio, dismantle your LSD and remove the crown wheel.

Dismantle your new open diff and remove crown wheel.

Install open diff crown wheel onto LSD and resassemble into new diff casing.

Job done.

Though you will likely need a special tool to undo the castellated nuts otherwise you will break them.

I don't know how much help this will be, but given the extreme cost of getting a 3.14 diff it must be worth a try. I have recently bough a crown wheel and pinion for a 4.09 diff for a scorpio from my Laidlaws a local ford dealer, it was only £150 approx from memory. I'm sure other ones are still available. Have you tried to buy them new from Ford. It would be much simpler and would give you new rather than worn parts.

Thanks for the replies, I think I read on another forum that Ford don't do the 3.14 any more.

Also could someone tell me, am I right in thinking that I can't use my 7" LSD in an existing 7.5" diff?

Cheers

Max

7" and 7.5" diffs are NOT interchangeable

Crown wheels and Pinions must be changed together as a they are a matched set set.
Colin Chapman did mix a crown wheel and pinion from different diffs but ran it for about 50 miles with metal polish to mesh the gears then took the diff apart and replaced all the bearings etc.

Lotus Seven Story, i did not make it up

quote:

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Originally posted by snapper
Crown wheels and Pinions must be changed together as a they are a matched set set.
Colin Chapman did mix a crown wheel and pinion from different diffs but ran it for about 50 miles with metal polish to mesh the gears then took the diff apart and replaced all the bearings etc.

Lotus Seven Story, i did not make it up

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I beleive that even though you can swap the CWP onto the LSD, you should re-shim it due to the different tolerences in the diffs.

I know mine is different but I have just done this with my Atlas axle. When I swapped the CWP like for like onto my new Quaiffe diff it would not turn due to the mesh being too tight. I had to pull off the side bearings and adjust the side shims to give the correct amount of backlash.

Mark.

Well I'm not scared of getting my hands dirty and do come from an engineering background, even so, this is beginning to sound like quite a major operation...

On another note I see that Freelander Diffs are more readily available in the magic 3.1x ratio. What would be involved in a conversion? Anyone done this?

Thanks again for the input guys, appreciate it.

Max

Another question... What is the best diff oil to use and where can I get it?

I get fairly heavy knocks from the diff area when shifting 1st,2nd,3rd. I can usually avoid it by either shifting at really low rpm/load.

Being the mechanically sympathetic type I've started avoiding 1st gear altogether (I can pull away in 2nd quite comfortably). I understand knocking is something you have to live with to some extent in a BEC but are there any suggestions to improve things? It does seem to be slightly excessive... Will different diff oil make a big difference here?

Initially I thought a TRT prop was a great idea as bikes always have a cush drive to protect the gearbox from shocks, although having read through the forums the general opinion seems to be that a TRT doesn't really make much difference...

Basically I want my gearbox to have the easiest time possible, any suggestions towards this cause? I have always run Pro4 fully synthetic in my bikes and have just changed to this in the car, it has cured the slight clutch slip I was getting when hot but doesn't seem to have improved the shifting situation.

Any guru's with wisdom to share?

Max

Have used both a Sierra LSD and currently a Freelander, and would not consider using a Sierra diff again. The Freelander, being mounted on rubber bushes is much less prone to the heavy "clonking/banging" on changing gear.