V8 90 transfer box ratios

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ranger1
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V8 90 transfer box ratios

Postby ranger1 » Thu Jan 08, 2015 1:08 pm

Whilst playing at the Christmas do at Fellbeck my transfer box gave up. I ended up on the back of an RAC wagon to get home. OK so far, no probs.
My local LR garage have removed the transfer box and confirmed that there are lots of metal bits lying in the bottom where they shouldn't be, so i need another transfer box. This is where it gets interesting, and where my knowledge is totally lacking. The engine is a 3.9 v8 with auto box. The transfer box has the numbers 29D stamped on that indicate it is a 1:1.19

I have contacted several people to try and source one and my garage suggest that I should be trying to replace like with like. But another garage has suggested that the 29D is the wrong ratio for the 3.9 and that a 1.4 would be better as it would give a higher top end. I have been told that in low box they are all the same anyway, so its really its on road performance that will be affected. Anybody got any thoughts? Replace like with like or change to a 1.4.

Help!!

Nigel

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davew
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Postby davew » Thu Jan 08, 2015 1:43 pm

Change to 1.4 without any doubt, maybe a 1.2 (your current box) will work but with your tyres 1.4 will be better. If you come across a 1.6 I think that'll work even better for you but 1.4 are much easier to get hold of.

The 1.2 you have only works well with 205/16 tyres, any bigger than that and the V8 and auto don't work well on the road as it's over geared, leading to poor shifting and constantly needing to kick down on hills when cruising. You can get away with over gearing on a manual and give yourself a better cruising MPG but with an auto it can make driving it hard work and ruin your MPG.

I assume the transfer box that is on it now was the original one that was fitted to the engine and gearbox combo when it came out of the donor vehicle which would have been a Range Rover or Discovery.

ranger1
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Postby ranger1 » Thu Jan 08, 2015 2:05 pm

Thanks Dave. Yes, I am pretty sure that the 29D was original fit for the classic RR and early LR90 V8s. I am ringing round at present to find out what is available. Will start to look for a 1.4.
Cheers

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davew
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Postby davew » Thu Jan 08, 2015 2:08 pm

It's worth noting (especially when looking for a replacement) that the number stamped on the transfer box isn't a reliable indicator of the actual ratio. There are a fair number of boxes that have had ratios changed since they left the factory - a lot of TD5 Defenders had their ratios changed to 1.2 after getting them tuned and many of those were done by changing the gears rather than the box. It's always worth double checking manually - mark the input gear at 12 o' clock, turn the output flange (diff lock engaged) one full revolution so the input gear moves clockwise. If the input mark is between 2 and 3 o' clock you have a 1.2, 5 o' clock is a 1.4, 7 o' clock is a 1.6.

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Rod
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Postby Rod » Thu Jan 08, 2015 8:11 pm

Dave is there no end to your knowledge of landrover things can you sleep at night
Stercus fit !

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Matthews
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Postby Matthews » Sun Jan 11, 2015 3:04 pm

I have a 1.6 that I used to run in my 110 , (V8 auto) but you anre second in the que for it if you are after one .
Matthew

ranger1
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Postby ranger1 » Tue Jan 13, 2015 9:56 pm

Thanks to all. Have got a 30k 25d box,its a 1.4 so will see how that goes.
Nigel

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Matthews
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Re: V8 90 transfer box ratios

Postby Matthews » Thu Jan 15, 2015 9:23 pm

Make sure the diff lock lever is adjusted properly so it locks in and disengages properly then you won't kill this one :shock:


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