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New gearbox for '74RR Classic


SORNagain
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Hi Chaps

I recently got my old RRC a new MOT and back on the road after nearly 10 years. Either I have gone soft or got some of my hearing back, but it is WAY noisier than I remember - and I think a new gearbox will be in short order.

It currently has the original gearbox & transfer case in one (lt35?) which makes more noise than the engine at idle when I let the clutch out (layshaft bearings?), and seems like it is going to explode in a shower of cogs beyond about 40mph. It's got oil in it....

I have an autobox which was originally intended to replace it but I can't bring my self to fit it - I kinda like shifting!

So...hopefully I can tap some knowledge on my replacement options. This is what I think I know so far:

1. A santana would be strongest, but on the rare side. Given the rather tame offroading I am likely to do probably un-necessary. Annoyingly I turned one of these down about a year a go!

2. R380 next preferred alternative. Looking at ebay I think this will be too expensive for me though.

3. LT77 most likely.

I guess I have to look for one off a V8 with the right length bellhousing - so that means off a disco right?

Also I have a 1.4:1 LT230 off a TDI which I intended to fit to lower the ratios to suit the bigger wheels. I was thinking about this the other day and thought why, on a diesel engine which revs lower, would you lower the ratio rather than raising it? Have I bought the wrong one?

Finally, is there any funny stick arrangements I should be aware of. I'm hoping for a fairly drop-in replacement. (looking forward to being rid of the vacuum difflock tho!)

Saw this as an example:

http://www.ebay.co.uk/itm/170974830323?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649

...is this what I'm looking for?

Sorry about the load of questions, but the more I looked the more I confused myself! Need an expert to tell me how it is. :blink:

Rob

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The box you have in there now will be the LT95. Same box as used in the early Rangies, Stage 1 V8s and the 101 Forward control.

I believe LT77s were fitted in RRCs behind the V8, so that could be an option.

Not sure what you are meaning with the TDi transferbox? AFAIK Tdi RRCs and Discos all had the same 1.2? The 1.4 was only used in the Defender to my knowledge. LT95s had a couple of different ratios for the transfer gearing, but I can't remember what they were.

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Thanks Guys,

The 1.4:1 transfer case in the Defender makes much more sense; I thought it was specific to the TDi.

I hadn't thought about reconditioning the existing box, but that could be an option. On balance I think I would probably benefit more from having 5 gears rather than the overdrive (which feels like it multiplies the explosion risk by a factor of two when I engage it!) The strength of the box probably isn't a big issue for me.

I would like to rebuild a gearbox - never done one before - but I would need to swap another in as it is likely to take me ages.

So will a V8 discovery gearbox like this one just drop in?

http://www.ebay.co.uk/itm/170974830323?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649

I don't mind chopping the transmission tunnel about a bit. Obviously the handbrake linkage would all change anyway.

Rob

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Your currant box as stated will be a LT95 wich is a very strong box with integrated transfercase, you could fit an lt77 or r380 but to keep the correct looks I think you would want a long stick version, I'm not sure you can achieve this simply with an r380.

Unless your vehicle is radically messed about with I would look at a rebuilt lt95 and overdrive I think.

Will.

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Well....just bought the LT77, so I'm in for it now!

The (short) stick looks like it will emerge in approximately the right place, but the Lo-Hi & Diff lock selector might end up behind the heater matrix somewhere. :blink:

Fortunately those linkages look fairly easy to move towards the rear. The truck isn't in any condition approaching original so I have no qualms cutting the tunnel out to suit.

Hope I don't have to move the gearbox mounts though.

The new box looks like it has connections for an oil cooler. Anyone know if I can I get away without using these?

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You should find it will fit in no problem, and the gearbox crossmember will bolt up to existing holes. Just done the same thing on mine using a Disco R380 box, and it was far easier than expected.

gearsticks come up well clear of the heater unit, just had to alter the hole in the transmission tunnel.

It also meant I could get rid of the hopeless multi-link handbrake mechanism that never worked and fit one from a Discovery - again very easy and considerably more efficient.

even with no soundproofing or carpet and a gaping hole round the gearstick till I sort it all out, it's considerably quieter than the LT95 ever was!

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Now that is the best news I've heard all day!

I've just been out there and concluded the mounts can stay put, keeping the gearsticks the same is even better news. Thanks Eightpot!

Any idea about the oil cooler? Surely a 'bog brush' style automatic one will do the trick?

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