2 interesting things i found out about the p38

[andrew e]

1, the seats have heaters inside them, but they are not hooked up (the wires are there)

2, The diffs spin in the opposite direction, due to the viscous transfer which works like a limited slip diff (unlike a conventional constant AWD transfer that acts like an open diff). So this is the reason that the front and rear centers are not interchangable.

Ok, that doesnt sound right, the diffs do turn in the same direction, but the crownwheels are on the same side, where they are normally on the opposite. The tailshafts turn in the same direction, whereas they normally turn in the opposite direction.....confused? ok i'll shut up.

Andy

[Blknight.aus]

urmmm...

the crown wheels would need to be on the opposite sides and the shafts would have to counter rotate for it to be anything unusual.

[Scouse]

Thanks Andy. I didn't know about the seat heaters but some D2s (with leather) have the elements already in place too.

Interesting about the diffs too. I have seen the later Defender diff (Rover type) referred to as a P38 diff. Does this mean that the Defender is similar? Or is it the front diff oin the P38 that's skew-wiff?

[Scouse]

the crown wheels would need to be on the opposite sides and the shafts would have to counter rotate for it to be anything unusual.I thought Andy was trying to say that both crownwheels are on (say) the N/S & therefore are on the opposite sides when the centres are compared side by side.

[andrew e]

urmmm...

the crown wheels would need to be on the opposite sides and the shafts would have to counter rotate for it to be anything unusual.


OK i am wrong. I got very confused:confused:


but hey atleast the seats DO have heaters (HSEs anyway)

[Blknight.aus]

I think what your getting at is that if with all the wheels off of the ground and you grab the rear prop shaft then turn it that the front shaft will counter rotate but as you have the VC the front shaft turns in the same direction

[andrew e]

I thought Andy was trying to say that both crownwheels are on (say) the N/S & therefore are on the opposite sides when the centres are compared side by side.


correct, this is what i was trying to say, but blacknight has me seccond guessing myself now. I am going to have a better look on monday.

[Blknight.aus]

my monies being on the diffs being the same (crown wheels on left hand and right hand side of the vehicle) with the propshafts rotating in the same direction.

the only time Ive ever seen counter rotating shafts is on some trucks that use a direct gear drive to get front output, same concept in gear drive as a normal transfer case but instead of driving a diff the rear output is always driven and the front out put is a dog engagement on a gear that hangs from the rear output gear.

[jbell110]

sorry wrong section


Jeff

[wayneg]

Thanks Andy. I didn't know about the seat heaters but some D2s (with leather) have the elements already in place too.

Interesting about the diffs too. I have seen the later Defender diff (Rover type) referred to as a P38 diff. Does this mean that the Defender is similar? Or is it the front diff oin the P38 that's skew-wiff?

Not sure the exact models years but having recently found out late defender 130`s have exactly the same diff as the p38. They could also be optioned on the 90`s

[zuk]

Hey Andy if the diff is like a slip diff dose that mean you should not use an additive like molycote it will bugger up a wet clutch or normal slip diff.

Molycote M55 stops metal to metal contacted.

[PhilipA]

Now I am putting on my clairvoyant hat and foreseeing that what Andrew is trying to say is that the crownwheels on the diffs are handed unlike all previous Land Rovers where the front diff is the same as the back diff and just goes backwards.IE the diff is running on the "wrong or back side of the crownwheel".

AFAIK Ashcroft replacement CW&Ps are handed so should be stronger than otherwise when fitted to the front.
I have a rear Quaife in the front of my RRC. ( and yes I have checked with Quaife and it works backwards according to them)
Regards Philip A

[wayneg]

Hey Andy if the diff is like a slip diff dose that mean you should not use an additive like molycote it will bugger up a wet clutch or normal slip diff.

Molycote M55 stops metal to metal contacted.

The front and rear diffs are std not limited or locking so stick whatever you want oil wise in them. I would stick with the approved 70/90 synthetic gear oil.
The transfer case attached to the gearbox takes Dexron 3, The Viscous swims in this dexron 3 but the business part works with an internal silicone ( i think) substance that allows limited slipage after which it effectively locks up the prop shafts front to back like a central diff lock. Not quite sure what the central diff behind the viscous and within the transfer case does but there is a diff in there. Maybe it turns one prop one way and the 2nd prop the other way allowing axle diffs of the same type to be used.

I have seen both front and rear diffs out of a car the same time and they are identical ( both 4 pin) There is only one part number for front and rear now...
Part # TBB000270
Superceded Product Codes: STC3893 TBB100830 TBB100900 TBB100830 TBB100840 FTC3483 FTC3489 FTC3490 TBB100830 TBB100840 TBB100900 TBF100210 TBB100840

For more info on viscous coupling see........
HowStuffWorks "Viscous Coupling" (http://auto.howstuffworks.com/differential5.htm)

[Scouse]

Now I am putting on my clairvoyant hat and foreseeing that what Andrew is trying to say is that the crownwheels on the diffs are handed unlike all previous Land Rovers where the front diff is the same as the back diff and just goes backwards.IE the diff is running on the "wrong or back side of the crownwheel".

Front & rear are interchangeable like 'normal' Land Rovers.

[PhilipA]

Front & rear are interchangeable like 'normal' Land Rovers.
Then I have NFI what he is referring to.
I know some recent model has "handed diffs"
A 38A has a centre diff also in addition to the VC.

Regards Philip A

[Scouse]

Well, as far as I know they're interchangeable :angel:.

[p38arover]

Now I am putting on my clairvoyant hat and foreseeing that what Andrew is trying to say is that the crownwheels on the diffs are handed unlike all previous Land Rovers where the front diff is the same as the back diff and just goes backwards.IE the diff is running on the "wrong or back side of the crownwheel".

I shall go and check. I have a pair (F & R) of standard CW&P in the garage. I bought them off Hardy Neale when he put 4.1:1 CW&P kits in his Rangie (now owned by PaulP38A)

[Hoges]

at one stage the rear diff was 4 pin while the front diff was 2 pin. With the Thor upgrade 4 pin F&R were introduced. As to 'handed'... BIIK:eek: I'm left handed anyway:D

[PaulP38a]

I shall go and check. I have a pair (F & R) of standard CW&P in the garage. I bought them off Hardy Neale when he put 4.1:1 CW&P kits in his Rangie (now owned by PaulP38A)

a-ha! now I know who to bother if/when I put the Hard Rangie back to stock :p

[d2dave]

Thanks Andy. I didn't know about the seat heaters but some D2s (with leather) have the elements already in place too.

My D1 has elements in the seats that are connected, with the switches in the same panel as the fast glass switches. Very nice too in winter, when there is ice on the bonnet.

Dave.

[rick130]

Hey Andy if the diff is like a slip diff dose that mean you should not use an additive like molycote it will bugger up a wet clutch or normal slip diff.

Molycote M55 stops metal to metal contacted.

and not needed if you use a good quality diff oil as they already contain sulphur EP compounds (or better still borate esters in some) that also prevent metal to metal contact in high speed/high load/high heat conditions.
Generally, Moly-di-sulphide is a no-no with rolling element bearings.

Moly is brilliant in low speed/high load areas where boundary lubrication may be needed. (eg. sliding splines, CV's)

Our Patrol has done 400,000km now and used mostly for towing and the rear diff makes no sounds and it still has the original bearings and seals.
It's only used premium diff oils since new, no additives.

[Scouse]

at one stage the rear diff was 4 pin while the front diff was 2 pin. With the Thor upgrade 4 pin F&R were introduced. As to 'handed'... BIIK:eek: I'm left handed anyway:D4.0 cars (early at least) had 2 pin diffs front & rear.
Early 4.6 cars with rear wheel TC had 4 pin rear diffs.
Later 4.6 cars had 4 wheel TC & had 4 pin diffs front & rear.

So the P38 isn't exactly the same as D1s & Classic RRs in that the front & rear diffs are identical but they are technically interchangeable if need be.

[p38arover]

I noticed MicroCat lists a 2-pin rear diff FTC3563 which is the same as the front on early P38A. Were they for non-rear TC cars?