'73 Range Rover - which gearbox choice?

[gn3dr]

Hi

I have a '73 standard Range Rover which I am planning to do a few mods to. I am going to convert to fuel injection (probably Megasquirt) and was also looking at changing the box for a 5 speed for more relaxed cruising. (It is really only used on the road at the moment). I was planning on buying a complete 5 speed injection Range Rover for parts)

The current 4 speed is working fine.

But.......I read in the technical archive on here that people were recommending fitting an overdrive to the 4 speed rather than changing to a 5 speed but I'm not sure if this was in reference to the person fitting a diesel 5 speed (are the diesel vs. petrol ratios different?) I'm also not sure if this was based on suitably for off-road or on-road driving.

So I'm asking the question here for clarification - what's the best route to take and why - should I fit an overdrive to the current 4 speed or is it better to change the complete box for a 5 speed.

Appreciate your inputs.

[Dale Simpkins]

So I'm asking the question here for clarification - what's the best route to take and why - should I fit an overdrive to the current 4 speed or is it better to change the complete box for a 5 speed.

Appreciate your inputs.

Hi,

I have a '71 RaRo, 4 speed box with an overdrive fitted, and I think it's fine. Never tried a RaRo with a 5 speed, so I can't compare. Reading up on RaRo overdrives it appears that they were not as popular as in Series Land Rovers. One of the reasons for this was apparently an increase in "clunking" in the drivetrain on takeup of power. I have to say that if you're driving a '73 RaRo then you'll probably not notice this due to 33 years of wear and tear on the drivetrain anyway!

My vote would be for an overdrive unit. IMO because it's more original and befitting an early Range Rover, but if you're being really anal, then that's wrong as it wasn't an option until 1978!

Something to bear in mind with a Range Rover overdrive is that unlike those fitted to Series Land Rovers, it should only be engaged in third and fourth gears (high range) only. The V8 produces so much torque that in lower gears it would very quickly shred an overdrive.

[Diff]

The 4 speed is regarded as one of the strongest boxes ever fitted to a Range Rover, though it is a bit agricultural in its operation. An overdrive is the simplest solution to get better high range cruising. Changing to a later 5 speed will involve changing gearbox mounts, and possibly propshafts, possible changes to the floor/tunnel(cause the levers etc are in different places) as well as the box itself. In theory you will get a smoother change with a newer 5 speed, but motorway cruising will pretty much be the same in 5th gear as it would be in 4th+overdrive.

Regards,

Diff

[gn3dr]

Thanks for the replies folks.

[FridgeFreezer]

For info, I saw a lot of the overdrives at Sodbury, average price was around £80, if you look round you'd probably find one attached to a gearbox for ~£100 as people seem to want 5 speeds these days. The 4-speeds are very strong though, I'd stick with it.

[gn3dr]

For info, I saw a lot of the overdrives at Sodbury, average price was around £80, if you look round you'd probably find one attached to a gearbox for ~£100 as people seem to want 5 speeds these days. The 4-speeds are very strong though, I'd stick with it.

I've seen it mentioned a lot but what is "Sodbury". I assume it's some kind fo Land Rover show / parts sale. How often is it run?

[geoffbeaumont]

I've seen it mentioned a lot but what is "Sodbury". I assume it's some kind fo Land Rover show / parts sale. How often is it run?

It's a land rover autojumble, run a couple of times a year at Newbury showground - see here.