Thread: 4.11 cwp

It wont affect the transmission.

If you're running 4.11 and 285/75's it will correct the gearing back to standard over all, so if you're already running the big tyres, then using your friends theorys it will actually be better for the gearbox. Between the engine and diff it will make absolutely no difference apart from the extra load of the heavier tyres. Its between the diffs and tyres that all of the changes will occur.

Originally Posted by markb

Can anyone tell me if there are any disadvantages to fitting 4.11 diff ratio's to a 3.9 classic rangie running 285/75/r16 or 300tdi rangie running 265/75r16 soon to be 285/75r16. I have had a couple of people try to talk me and my brother out of them. One reason being the tranfer case wont like the extra speed. The 3.9 has the viscous transfer with the 300tdi has the locking tranfer case.

Only reason against (that I can see) is the CWP and axle halfshafts will be under a higher load due to approx 15% of additional torque available (as a result of of the higher diff reduction ratio).

Anything upwards of the diff will be at the same load as before or less (depending on how much traction you have at the wheels).

Originally Posted by markb

Can anyone tell me if there are any disadvantages to fitting 4.11 diff ratio's to a 3.9 classic rangie running 285/75/r16 or 300tdi rangie running 265/75r16 soon to be 285/75r16. I have had a couple of people try to talk me and my brother out of them. One reason being the tranfer case wont like the extra speed. The 3.9 has the viscous transfer with the 300tdi has the locking tranfer case.

It's still 4 1/2 months away to be april fools day is what I'd be telling the person who told you that

All of the above is true and correct, if you got the dollars go the 4:11's, they drive much better, I cant wait until I can find a way to justify it to the minister for finance

Thanks Guys they will be the next project for the rangie>

Originally Posted by markb

Thanks Guys they will be the next project for the rangie>

I've just changed the CWP on my 3.5 V8 Disco. I'm running 285/75/R16's and the difference it has made is unbelievable. It is definitely something I should have done ages ago.

I was told by a few people that it would increase my fuel usage, because the car would be revving higher to do certain speeds. But what has actually happened it I'm now getting better economy because the car is not working anywhere as hard as it used to.

They are by far one of the best modifications I have done to my Disco.