Thread: series 3 gearbox conversion

It would be best to buy a four speed Isuzu 3.9 diesel county or stage one ( range rover running gear series 3 springs and body.
They are a little noisy but, in my opinion the are the pinnacle of tow vehicles. You might even find a turbo one as some come from factory fitted.

I had a series 3 with a Nissan five speed box from marks 4wd.
it also had an ED 3.3 diesel that was a very good combination and a regret selling it. It went as good as any 2.4 defender and rely good on fuel.

I never towed anything to heavy with mine, but i know an old bloke at Oakey Qld. who used the same Nissan five speed. His son had a car don't remember the engine he ran, although they were regularly stripping main shafts.

You are correct in doubting your current setup.
If you don't yet need to do up your gearbox main shaft you soon will.
All land rover boxes seem to destroy main shafts. I had one with with a 4.1 falcon and it did the main shaft on me.
I have heard that a factory trained land rover series guru indicated that the after market engines that people fit have far greater possible rpm that the original design of the lubrication system intended. Add to that people only fit larger engines. Say replacing a 2 & 1/2 with a 4.1 with nearly doubling the power. It only make sense that something must give, if its not rear axles it will definitely be the main shaft. No one would fit a jumbo jet engine to a DC 3.

Hi Fingers
If you get a nissan 720 transfercase basically you can run any manual gearbox that will bolt up to your 202.I dont know how strong the VK commodore 5 speeds were,even a 1 tonner 4 speed were ok,the trimatic autos were ordinary.
The 720 transfercase is reputed to be one of the strongest beasts made(fitted to a hilux style 4WD called the 720),the beauty of it is its remote mounted,ie not bolted to the gearbox so it can be fitted to any motor/gearbox combo.
Not sure if it has a tailshaft handbrake,but there are disc brake handbrake kits available.
Andrew

Originally Posted by fingers

G'day chaps, I am a new member, I have an old 80 model series 3 with a 202 holden and a high speed transfer box all on big tyres, she sits on 2400 rpm @ 100kph. I would like to know if any one has had anything to do with gearbox conversions. I have heard of a Nisson box coupled to a LR bell housing and a LR transfer case. I would like to hear about any gearbox conversions and comments. I want to tow a very large van around australia next year and am worried about the standard box doing the job. (it is being removed at the moment for the third time)
cheers ,
Fingers

Fingers,

Can't speak to the question, but I'll do you a good price on my Stage 1. They're a Series 3 with a 3.5L alloy V8. Not light on fuel but plenty of torque and power (better output than the Isuzu 3.9 but less economical). Best bit - the LT95 4 speed transmission - as used in the Army Landrovers including the 6x6 Perenties. And they have the Salisbury rear dif. In short, properly engineered for the job. The 3.5 is a good gas conversion or you could just carry heaps of fuel. In ordinary use they are only slightly less economical than the 4 anyway - don't know about the 202. They come in all body styles except shorties. For the changover price (negligible) and with all your modifications and accessories bolting straight on they're pretty reasonable.

Steve

There's one on ebay at the moment:

http://cgi.ebay.com.au/Isuzu-4BD1-3-...QQcmdZViewItem

Originally Posted by LandyAndy

Hi Fingers
If you get a nissan 720 transfercase basically you can run any manual gearbox that will bolt up to your 202.I dont know how strong the VK commodore 5 speeds were,even a 1 tonner 4 speed were ok,the trimatic autos were ordinary.
The 720 transfercase is reputed to be one of the strongest beasts made(fitted to a hilux style 4WD called the 720),the beauty of it is its remote mounted,ie not bolted to the gearbox so it can be fitted to any motor/gearbox combo.
Not sure if it has a tailshaft handbrake,but there are disc brake handbrake kits available.
Andrew

I have never heard anything about the 720 T-case being especially strong. What you are talking about though is a divorced case, which is nothing special - a few models of nissan had it (MQ patrol included), and the LT230 (or series T-case come to that) can be easily modified to be a divorced case.

Fingers - If you are happy with the holden 6, look for a strong 5-speed manual or 4-speed auto that will bolt to your engine, and that has an adaptor to a series T-case or LT230. (the divorced case installation is also an option).

For a round Australia type trip though, keeping everything as standard as possible is good though, so the Stage 1 option is not a bad idea.

How much room is there? On my 109 there is only around 5 inches to play with before the cross member gets in the way. If this is not an issue I'd go for a supra 5 speed or celica box and do the divorced case option.
(202 to toyota box adapter kits are common)

BUT - IMO you don't need a 5 speed - 2400 revs at 100k is pretty good, what size tyres are you running to get this? I'm at 2900 rpm at 100k with 31". (high speed t-case).

other options - toploader/ single rail. You can get bellhousings to mount these behind a 202 and these have been adapted to a series t-case before. I'm doing a np435 at the moment, if you don't mind mucking around this is a good box. 6.7:1 first gear and its the same length as a series box, so the crossmembers and prop shafts remain unchanged.

How about a v6 and t700 combo ?

Guys be wary of the Nissan 720 transfer case I have done them up in the past and they warp the casing resulting in them being quite noisy.
Maybe fairly strong I never saw one break.

This may help

http://www.outerlimits4x4.com/PHP_Mo...hp't=22264