does defender transfer box fit on disco 300tdi?!

Hi,

I have 235/85/16 tyres fitted to the disco, which means its a little slower on acceleration and has to work the clutch a little more on pullaway.

as defender has these size tyres as standard (ish) i was thinkin put the transfer box on and would give a better suitability to running with the new tyre size.

is this a common thing and can be done?

thanks

Yes and yes

The box should fit, but the ratios are different between Def 90 and
Def 110.

The trans box ratios are something like Discovery 1:1.2; Def 90 1:1.4 & Def 110 1:1.6.

Do you know which def your trans box came from?

Do you really want to be screaming along flat out at 70? Most people fit disco tranny boxes to their defenders, run 235's or 265's and don't have any problems. The low ratio is the same so no issues if you like to go rock crawling or whatever.

hughesy said:

Do you really want to be screaming along flat out at 70? Most people fit disco tranny boxes to their defenders, run 235's or 265's and don't have any problems. The low ratio is the same so no issues if you like to go rock crawling or whatever.

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The OP has a Disco with 235/85/16 tyres so it's over-geared, so by fitting a def 90 1:1.4 transfer box that should balance out the gearing quite nicely.

thebiglad said:

The OP has a Disco with 235/85/16 tyres so it's over-geared, so by fitting a def 90 1:1.4 transfer box that should balance out the gearing quite nicely.

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Strangely enough I was able to read the original question myself. I currently run 265/75's on a 200tdi disco and have run the same tyres on a 110 for some time, so I think I can understand what he was asking, and have the necessary experience to give advice on the subject.

I've a 1.4 in my defender and 265/70/16 insa turbo and either could do with 1.6 or more power.
also consider changing speedo drive to correct speedo

Thanks for all the responses!

I understand about the flat out at 70 thing, but is that only with the 1.6 box? currently it keeps at about 2500rpm ish at motorway speed on up hills am finding i have to change down to 4th and worse when towing. is that normal or am i lacking power from the engine?

I dont really go much above 60 on a run as no anti roll bars and lift gets a bit boat-ish and so 60 is comfy.

so im just lookin to improve pull away and general pottering about abilities as i dont do too much motorway. would the 1.4 ratio box be a good compomise without blowin it up on te motorway with a 1.6?

I dont have a new transfer box as yet, not really knowing what to look for... not too hot on defenders so id imagine it would have to come from a 300tdi defender??

Thanks again

should be better, what you have to realise is by putting wheels with larger rolling radius you make gearing higher, so you then either need more power or try to lower total gearing to get a happy medium.

A 300 tdi in good nick should have ample power to pull 235 or 265 tyres and a disco transfer box. But if you want lower gearing that's up to you.

Yea Try genuine 37 inch tyres and a disco 1.22 transfer box 200TDI! on a bloody heavy 90. I'm going 4.7 ratio asap because my low range is horrible. Should be swaping brakes over to my spare rear salisbury tomorrow. and cleaning up a decent front axle casing.

But TBH I would stick with your current setup and give it a FULL service unles you do alot of towing trailers a 300 should pull the ratios alright no probs. If you really want to swap the transfer box go for it but I think you would be wiser getting the most out of your engine.

Hi all i have a disco 300tdi auto will a 1.4 defender transfer box fit. Running 265/75s and is very slow up motorway sliproads. Also on long drives the transmission temperature light pops on. Will this cure the problem

Harrydickerson1990 said:

Hi all i have a disco 300tdi auto will a 1.4 defender transfer box fit. Running 265/75s and is very slow up motorway sliproads. Also on long drives the transmission temperature light pops on. Will this cure the problem

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Hello there Harry. Your transmission oil temp light is coming on because:

1. It's faulty - not at all unknown. Replace the oil and replace the temp sensor and then see how you get on.

2. As you know, putting larger diameter tyres on has lengthened the final drive ratio (FDR); by changing to a 1:1.4 tranny box you will shorten it again. On the current set-up your torque converter is probably having to work too hard, so shortening the FDR will allow it to get into top gear torque lock-up easier, therefore taking the load off the torque converter.

If I were you I would be changing the oil and temp sensor and in addition I would use a manual over-ride on gear selection when coming up to hills.

You may well find that is enough to cure your issue. I have 265/75's on my manual box TD5 and I find it is beneficial to hold the lower ratios a little longer.

Good luck

Dave