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What gearbox can I fit, 2 wheel drive

Posted: Mon Feb 03, 2020 3:35 pm
by truckdoctor
I'm currently looking to replace the flathead v8 and manual (very short ) gearbox from a 47 pickup . There is limited length due to a chassis crossmember that cradles the end of the box . This cannot be modified so have to fit the new engine and box forward.
I'm sure I'm probably going over old ground but would like to know what can be done with the seemingly plentiful rover engines from the range rover. They all seem to be automatic with a transfer box and wonder if there is an attachment that could be fitted after the transfer box is removed to facilitate a prop shaft fitment maybe a housing with a support bearing.??
If not what gearboxes are low cost and easily available that will fit without too much hassle. The shorter the better. Thanks

Re: What gearbox can I fit, 2 wheel drive

Posted: Mon Feb 03, 2020 6:41 pm
by ChrisJC
I'm guessing here, but I would think the 4 speed manual box from a Rover P6 would be the shortest.

Then you are getting on to the LT77 and later boxes which are longer because they are 5 speed.

I used an R380 + very short bellhousing from Ashcroft Transmission (which is meant for a 4 cylinder engine), then a 4-8 cylinder adaptor plate.
You can get a 2wheel drive R380.

That was the shortest I could come up with (that would take 300BHP though!).

Looks like this:

Chris.

Image

Re: What gearbox can I fit, 2 wheel drive

Posted: Mon Feb 03, 2020 6:46 pm
by harvey
truckdoctor wrote:
Mon Feb 03, 2020 3:35 pm

If not what gearboxes are low cost and easily available that will fit without too much hassle. The shorter the better. Thanks
Autos? Borg Warner 35/65/66, GM180, Chrysler Loadflite, ZF4HP22/24. Out of those the shortest you could make would be a BW35 with a short rear tailshaft, or a BW65/66 from a Jag as they have a short tailshaft as well, the 65/66 being the better option of those two. The ZF is a good box but has a lot more going on at the front end making it longer.

Manual? Rover P6B 4 speed, which is short, but not a good box, or LT77/R380.

Re: What gearbox can I fit, 2 wheel drive

Posted: Tue Feb 04, 2020 6:27 pm
by truckdoctor
Thank you for all your replies, seems as though there are many options open mostly very aged though. I wonder were there any thoughts or options to remove the transfer box from an auto and making /getting a method for supporting the output shaft and directly fitting a prop shaft instead of replacing the long shaft.

Re: What gearbox can I fit, 2 wheel drive

Posted: Wed Feb 05, 2020 9:44 am
by DaveEFI
The box on the RR is likely a ZF 4HP. That comes in RWD versions too. Complete V8 Rover ones fitted to Sherpa ambulances etc, so not that easy to find. Or a BMW or Jag etc one, and fit the Rover bellhousing. Or fit a RWD tailshaft to a RR version which I believe involves changing the box output shaft too. It might be possible to make a shorter tailshaft too if you have the facilities.

Re: What gearbox can I fit, 2 wheel drive

Posted: Wed Feb 05, 2020 6:43 pm
by truckdoctor
Many thanks Dave, seems like I've much work to do.

Re: What gearbox can I fit, 2 wheel drive

Posted: Wed Feb 05, 2020 6:46 pm
by ChrisJC
The ZF4HP22 is a long box though, even in it's shortest form.
The only factory bellhousing for the V8 is the Range Rover one, and it's very long by itself!

Chris.

Re: What gearbox can I fit, 2 wheel drive

Posted: Thu Feb 06, 2020 6:35 am
by minorv8
There is limited length due to a chassis crossmember that cradles the end of the box . This cannot be modified so have to fit the new engine and box forward.
Why can´t you modify or move the crossmember ?

Re: What gearbox can I fit, 2 wheel drive

Posted: Thu Feb 06, 2020 6:15 pm
by truckdoctor
Rules and regs, if it was a few years ago the crossmember would have been replaced in a different position but somehow I see it as a challenge to find a way around tis issue and keep things as they are.
The price of theses lt77 boxes are getting growing by the day it seems and came across a jag s type manual that looks very short so having a look at this option while I wait for a lt77.