4.11 CWP or defender transfer case

[markb]

Hi All

I have an 87 Rangie Classic with a 300tdi I am currently running 265/75R16. I am going to go up a size in tyres to 285/75R16 . Now the 300tdi already struggles on take off and I regularly tow a trailer were I find I even need to use low range to get it going.
I am looking at fitting 4.11 cwp but a local Land Rover specialist has recomended a defender transfer case would be a better and cheaper option.
So what should I do.
Opinions please is one stronger than the other any other advantages and disadvantages.

[buzz66]

If you also want that lower gearing for low range as well as high range, then the 4.11 or 4.14 Diff ratio is the go.
The transfer case option will only affect the high range gearing.
You wont get any change out of $2,000 to do the Diff's. All things being equal you could get the gearing and overhaul the transfer case for the same money roughly.
If you are only really touring then id go the transfer case option and get it overhauled while your at it.

[Slunnie]

As above re 4.11 or 4.14's for the low range gains that the Defender transfer wont give.

[Blknight.aus]

buzz66 pretty much got it in one

the diffs will give you lower in high and low but cost you more

the Tcase will give you a lower high only but cost less.

if you dont need the lower low then the tcase is the most cost effective option.

The diffs are the technically better way to go.

[fitzy]

One thing to consider is that we all know that rover diffs are a weak point in the driveline. The 3.54 gears are as strong or stronger than any after market gears but are really still not up for hard use. But if you break a 3.54 gear set they are quite cheap to replace.
LT230's are quite strong and will take much more abuse than a rover diff.
So my reasoning is put your money where the strength is not the weakness.

[Slunnie]

One thing to consider is that we all know that rover diffs are a weak point in the driveline. The 3.54 gears are as strong or stronger than any after market gears but are really still not up for hard use. But if you break a 3.54 gear set they are quite cheap to replace.
LT230's are quite strong and will take much more abuse than a rover diff.
So my reasoning is put your money where the strength is not the weakness.
I'm not convinced that this is correct. The general consensus is that 4.11's are similar to factory 3.54's as despite the pinion gear being smaller, the materials and processes used are better. The 4.1 is weaker than the 4.11 due to gear ratios and loaded areas. The 4.14's are meant to be 25% or something similar when compared to 4.11's due to a better pinion to crown wheel tooth count..

[Bush65]

One thing to consider is that we all know that rover diffs are a weak point in the driveline. ...
Certainly.


... The 3.54 gears are as strong or stronger than any after market gears but are really still not up for hard use. ....
The 1st part is debatable.

Gear strength is largely affected by tooth size and width, material and heat treatment. Also by accuracy of tooth profile and pitch (manufacture) and alignment (alignment is also affected by distortion of components). Tooth loads, for a given input torque, are affected by ratio - load increases as pinion diameter reduces.

Rover 4.7:1 gears are much weaker than 3.54:1 gears, because the teeth are smaller. After market 4.1:1 gears also have small teeth. But 4.11:1 have larger teeth and 4.14: are larger still.

I agree with the 2nd part about not up to hard use. They can be improved by use of slippers to reduce distortion of the crown wheel - but if it comes to that, then other options to rover diffs should be considered.


... But if you break a 3.54 gear set they are quite cheap to replace.
...

Good point. Also easier to find, so less time off the road.

But it depends on how hard you use them. A lot of people (most) would not break 4.11:1 gears if they have addressed the main weakness of rover diffs.

The rest should probably not be using rover diffs, or should accept the breakages. These people would most likely benefit more from 4.11:1 diff ratio, than from 1.41:1 high range.


...
LT230's are quite strong and will take much more abuse than a rover diff.
...
Correct.

[markb]

Thanks for all your info guys.

Think I will get a set of 4.11:1 from rovacraft.

The front diff on my Rangie to my knowledge may have done almost 400000km, so could do with a new set of CWP. Not sure how many km the rear diff may have done as I bought it complete with a maxi drive locker about 50000km ago.

Is there anything else I should do to the front diff whilst i have the car off the road to make it a bit stronger?

[fitzy]

I ran 3.54 maxi drive diffs for 4 years without a breakage.
I then installed 4.11's and went through three gear sets in eighteen months. They were all new and professionally set up ( over $1000 supplied and installed ). It was very frustrating as the gearing was spot on. I went back to 3.54 gears and haven't broken a diff for over a year.
Earlier this year I put 30% low range and 1.4 high range gears the gearing is back on track .I have twisted two rear maxi axles and still the second hand installed at home gears are holding up.
Just my experience.

[Bush65]

Thanks for all your info guys.

Think I will get a set of 4.11:1 from rovacraft.

The front diff on my Rangie to my knowledge may have done almost 400000km, so could do with a new set of CWP. Not sure how many km the rear diff may have done as I bought it complete with a maxi drive locker about 50000km ago.

Is there anything else I should do to the front diff whilst i have the car off the road to make it a bit stronger?
Upgrade the carrier from the weak 2 pinion, e.g. locker or trutrac. If the pin breaks, as they are prone to do, it will probably take out the CW&P as well.

If it is still 10 spline then get a 24 spline locker or trutrac and some after market axles (rovertracs are good value).