transfer boxes

I have a defender 200tdi (disco engine) with a fully rebuilt Ashcroft lt77 gearbox and rebuilt 1.4 ratio transfer box in running 33s and averaging about 23mpg when on a run it feels like it needs another gear I have been told to put a disco transfer box on but as the ashcroft one has only been in 7 months I was a bit reluctant to swap it for a old disco one as I can't afford another from Ashcroft, would I notice much difference?

You would notice a difference but yours shouldn't feel like it needs another gear. What speed are you trying to do? The 1.4 is fine and I ran with it for many years until my box died and I replaced it with a 1.2 box from a disco. A lot quieter and cruised a lot better at motorway speeds so if youre after that then you could probably get a good bit of cash for your ashcroft box. I'm surprised you're only getting 23mpg though, that's bloody awful and 200tdi is supposed to be slightly more economical than the 300tdi (I disagree on this though, having run both my current 300 is definitely far better on fuel.)

Leave it be, be great on bigger wheels

Yeah when I mean another gear its just noisy on motorways etc and I do alot of traveling, I thought of buying a new Ashcroft 1.2 and then selling mine on as its still under warranty but I just wanted to make sure it's a good investment and modification

I think the poor mpg is down to tire size

Your tyres won't help with noise on the motorway. Unless you desperately need tyres that size might I suggest getting some smaller ones. Your ears and wallet will thank you.

You should definitely be getting better mpg than that, I was getting about 27 on my 1.4 box with my 110 and a disco 200tdi.When I then put in a disco box I didn't change my mpg but I drove faster. I gained about 8mph for the same rpm in top gear which made motorway mileage more tolerable.

Thanks for the advice guys I think my timing may be out slightly as its only been poor mpg since the cambelt was changed

valve clearances made a difference to my mpg i do believe as well as starting up easier.

23??????? bloody hell i get 34 out of my 300 110,but its on standard 235

I think the tyre size is the main issue with the mpg but I'm definitely going to check timing etc

to find out what changing the transfer box ratio will do to your gearing just goto to the ashcroft website ratio calculator. Gives you all the options and tells you the RPM's at various MPH to see the difference.

With a 1.41 xfer box 5th gear @ 70mph is 2742rpm (33" tyre/3.54diff)
With a 1.22 xfer box 5th gear @ 70mph is 2376rpm (33" tyre/3.54diff)

Id worry that a 200tdi wouldn't have enough power with a 1.2 box.

I average around 28 mpg on my 200tdi 110. I can get more. On a trip in Morocco when one of the group had problems with there 90 and we had to limp to a garage I got 35 mpg.
I run on 235's.

Mikeh thanks for that info so it won't be reving so high that's a bonus

Cheers

Dinky90 said:

Mikeh thanks for that info so it won't be reving so high that's a bonus

Cheers

Click to expand...

no probs. other option is to fit different diff ratios (ring and pinion gears) front and rear instead of changing your gearbox. Obviously this will change both high and low ratios. Ashcroft do a variety of ratios for £195 an axle, and they are heavy duty etc.

Also, stating the obvious :lol: that if you get smaller tyres as recommended int this thread then it will be revving harder still for a given speed as the rolling circumference will be smaller.

Im currently working all this stuff out for myself for an upcoming v8 90 auto project, as in that case the autobox 1st is like an LT77 2nd which would ruin the crawling ability off road.

My tdi with 1.2 is a lot more comfortable on the motorway, but doesn't really have enough power to keep up speed on even the slightest inclines...

if you sell your transfer box id be interested depending on price, just for you to keep it in mind. thanks

Ok will let you know what decision I make