Changing the gear ratios in Defender transfer box

G-P · Jul 22, 2018

Hi All,
I am currently looking into changing the gearing in my transfer box to this gear set https://www.ashcroft-transmissions.co.uk/lt230-ratio-changes/1-222-gear-set.html which is the same used in TD5 Discovery. Is this something that can be done without removing the box if I had access to a ramp or is it a case of removing the box and changing the gears on the bench?
Thanks,

GP

johnlad · Jul 22, 2018

If you wa t Discovery ratio’s fit a Discovery transfer box

payydg · Jul 22, 2018

Just get a second hand box with he right ratios, to buy the gears separately is expensive and you still have to fit them. You would need to remove the box

Brown · Jul 22, 2018

Yup, it's a box out job. The transfer box is quite a nice one to work on if you like rebuilding gearboxes or are beginner in those dark arts. Yes of course you may be able to get a secondhand Discovery box cheaper, but with new gears and bearings at least you know you've got what amounts to a new box. After all, there's usually a reason why the Discovery gearbox was taken out in the first place!

Kwakerman · Jul 23, 2018

Brown said:
After all, there's usually a reason why the Discovery gearbox was taken out in the first place!

You almost answered your own question, its a Discovery and probably rusted away!

Like the old saying goes, 'Land Rover only built the Discovery so that the Defender would have plenty of spare parts in the future'

dag019 · Jul 23, 2018

Kwakerman said:
You almost answered your own question, its a Discovery and probably rusted away! Like the old saying goes, 'Land Rover only built the Discovery so that the Defender would have plenty of spare parts in the future'

Was going to say the same thing

. The usual reason for removal is there is no discovery left to bolt it to!

G-P · Jul 23, 2018

Thanks for the replies, I suppose I could check/rebuilt a Discovery one then I always have the original to go back in. I take it the boxes are the same and are essential a straight swap.

Clunkbucket · Jul 24, 2018

I think I am right in saying there is quite a comprehensive video of how to change the gear ratio's on Ashcrofts website.

Hicap phill · Jul 24, 2018

Make sure you get the input gear if you buy another TBox.
Handbrake mechanism is different from LR to disco but you can swap over.(think you have to drill/tap 4 holes)
Just changed mine from a 1.44 to 1.22 .1st is a bit longer & need a bit more gas to pull off. Once going it's all fine, 5th cruises
Only problem I found was reverse was a bit too high. Struggled off road on a reverse hill but I had low box.
I run 750s which is a bit of a push on this box.

If your good with spanners less than a day to fit. Need a jack or crane to lift TBox.

Kwakerman · Jul 24, 2018

Speedo drive can be different (but changeable) depending if you have mechanical or electronic speedo.

dag019 · Jul 24, 2018

Hicap phill said:
If your good with spanners less than a day to fit. Need a jack or crane to lift TBox.

Can be swapped in an afternoon if everything comes of easily, but can take a whole weekend if it puts up a fight! You can use the discovery handbrake bracket, and it actually makes it easier to get a spanner onto the cable to adjust it.
If you are feeling strong you also do not need a crane. you lie underneath it and lower it onto you chest bench press style, with the reverse to fit while a helper on top lines everything up. Save lots and lots of time doing it this way but they are not light. I would not jack it unless you have a cradle to rest it in and even then it might be a challenge unless it is a custom one for the transfer box. They are not a sensible shape and tend to tr and twist and roll so you end up lifting it to keep it in line anyway hence doing away with the jack and just lifting form the beginning!

johnlad · Jul 24, 2018

Easiest way to re fit is to slide transfer box along 2 lengths of threaded bar approx 200mm long fitted in place of 2 bolts, it serves as a guide and saves the weight of the box resting on the oil seal and causing a leak further down the line. Once back on remove threaded bar and fit bolts.

Brown · Jul 25, 2018

Even with an apparently functional secondhand box I'd want to have a look inside to see the condition of the gears and see how the bearings were doing. You might as well make sure everything is as fresh as it can be while the box is on the bench and easy to work on.

Changing the gear ratios in Defender transfer box

G-P

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johnlad

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payydg

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Brown

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Kwakerman

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dag019

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G-P

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Clunkbucket

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Hicap phill

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Kwakerman

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dag019

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johnlad

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Brown

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