F50 Gearbox swap?


Does anybody know if I can use a five speed gearbox from the later daihatsu fourtrak to fit into an F50? Are the gearboxes pretty much standard apart from any changes required to propshafts?

Not a majer operation, if

Not a majer operation, if it's a Diesel box. The bell housing will bolt streight up. The primary shaft is the same. The gearbox mounting will be in the right place. Now the diffrences. The 5th gear moves the transfur box back. The front prop will need lengthening, and the rear shortening. Yes the flanges on the F50 props are smaller than the F70/5 transfur. Seen as you are cuting the props to length, use one end of an F50 prop and one enf of an F70/5 prop to make a new prop the right length, with the right flanges. Don't forget to get the props balanced (about £40 each).
Where is the doner box comming from? The transfur box from a Terbo Diesel is higher geared than from a non terbo. The Terbo gearing may be too tall for the 2.5 engine.
You also wont have a hand break, as the F50 has a transmition break on the rear of the transfur, and the F70/5 has a hand break to the rear wheels.
It is posible to bolt one type of transfur up to the other type of box, but not the other way around. Can't remember which way works (ie F50 transfur to F70/5 box, or F70/5 transfur to F50 box).
Aulternitivly if you can find an F20 box, that will bolt streight in (after putting the F50 bell housing on it (4 bolts)) and have a hand break, and be the right gearing, as the F50/20 gearing diffrence is in the axles, and have the right flanges, and if it's a 5 speed it'll have the right length props.
In fact is the only reason for changing it to get 5 gears, or have you brocken it? The very last (A reg) F50/20's had 5 speed boxes. I did have one for sale on e-bay, but I think i bined it, as no one wanted it.

Any veiws expresed in this thread by me are purely from my own experience, and (sometimes) falible memory. Hope my comments help, but please don't take them as gospel.

F50 - gearbox swap?

Hi Nev,

Thanks for getting to to me with all this helpful information.

Starting with the last question first. I already have an F50 Saxan Crusader fitted with a 5 speed box and it is just right for cruising at around 65-70mph. No strain. No falling apart feeling. (This is useful if you use the vehicle for going to work and have to do some short motorway trips).

I also have a second F50 Saxan Crusader which I want to do up. That has a 4 speed box. Anything over 55mph is taxing so I want to upgrade it.

The donor box would have been from a 1986, Model EL, Manual 4wd selection Fourtrak which is for sale on ebay.

But I think your comments have convinced me to look again in the F50/F20 space because of the handbrake complication I would otherwise have.

Thanks again for all your helpful comments Nev.

Cheers Dave

Another thought. Though

Another thought. Though this one is purly speculative. The 5th gear is just an overdrive bolted between the 4 speed box, and the transfure. The gearbox is the same from 1st F50/20 to last Indipendent. Only the transfure box changed, slightly. Could you use he long bolts, and 5th gear from a doner F70/5 and put it inbetween you exsisting 4 speed bex and F50 transfure?

Any veiws expresed in this thread by me are purely from my own experience, and (sometimes) falible memory. Hope my comments help, but please don't take them as gospel.



Thank you that sounds like a useful approach if the transfer ratios are compatible let me think about that one please.

But thank you for taking the time to reply. Much appreciated.

Cheers Dave