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LT77 or R380
Irony - 28/6/10 at 02:25 PM

Could anyone clear up a few questions for me regarding the above. I am building a RV8

The LT77 came in many different guises. As I understand it the later ones are the best. Some seem to have come off a V8 but some haven't. Do they all fit a RV8 or do you need a specific V8 bell housing? Can you get LT77 with different gears ratios? If so what ratios are best for my RV8?

The R380 is apparently a direct replacement for the LT77 and is apparently a better box all round. On 'the bay' there are lots of these but they mostly seem to have come from a 300tdi. Will this bell house fit to my RV8 or will I need a Specific R380 bell housing?

Thanks in advance?

t16turbotone - 28/6/10 at 03:01 PM

The Lt77 gearbox has different bellhousings for different engines, so you need a V8 B/H. As the R380 is a direct replacement you can bolt your V8 B/H straight to it. The best LT77 gearbox was fitted to the later rover sd1 3500 vittesse, it had stronger internals and different ratio fifth gear..i think. They done a special lt77 for sherpa vans which had a low 1st gear ratio. The R380 is the better and stronger box overhall and fifth gear postion is different to that of the lt77

ashcroft transmissions has a load of data online about these gearboxes

tomgregory2000 - 28/6/10 at 03:24 PM

quote:
Originally posted by t16turbotone
The R380 is the better and stronger box overhall and fifth gear postion is different to that of the lt77


Wrong, its reverse that is different

On the LT its across left and up (next to first) and on the R380 it is right and down (where 6th would be) also i think the r380 is longer as in the defender the engine sits further forward with the r380 on

v8kid - 28/6/10 at 03:52 PM

You can also get LT77 boxes off TR7's which with their puny engines give the box an easy life. Plenty available cheap as TR7's rust like billyoh and are not "desirable".

I hillclimbed a LT77 box for 3 seasons and abused it severely with a tuned 5.0 and it never gave any bother. More than I can say for the present UN1......

Simon - 28/6/10 at 04:27 PM

The other thing to consider is which final drive ratio to use - I have a 3.92 Sierra diff and it gives me a top speed of 117ish mph and 3500 rpm at 70. 1st gear is useless as is 2nd at times. Then there is the fuel consumption issue as a result.

ATB

Simon

t16turbotone - 28/6/10 at 04:31 PM

Sorry, typo error, i did mean reverse gear is in different postion, of course!

dazzx10r - 28/6/10 at 07:16 PM

R380 gearbox is physicaly longer than lt77, check out Landyzone for more answers.