Thread: County 4bd1 gearbox

I think the LT85 is a bit unfairly represented at times, mine did 250K behind the Isuzu before it got a bit 'rattly' in 5th and over 270K before it got noisy in all gears.

It never let me down, didn't break, just got noisy and was ready for a re-build / replacement.

There are 2 types of LT85 don't forget, the 'lightweight' divided case and the solid case version. I seem to remember reading somewhere that the solid case version (20C) is stronger than the divided case version (22C) See here for the difference when identifying the two: Aschroft Web Site

I bought a brand spanking new 'crated' 20C solid case LT85 for $2500, which I recently fitted to my Isuzu 110. Ashcroft Transmissions had bought them (presumably ex-military stock or new/old stock from Land Rover) and I then got it through their Australian agents (Rovacraft in Perth).

Jon

EDIT... Found the stuff about the solid case 20C being stronger than the divided case 22C - here it is:

1984 through 1991: The LT85 (85 mm shaft spacing) was used in all V8 110 and 90 Land Rovers. The LT85 was originally designed under contract by Land Rover for Santana in Spain and was considered to be a strong working gearbox. Rover purchased LT85 gearboxes directly from Santana. It is also known as the Spanish Box. This gearbox was used as originally designed until 1988. A cost reduced, lighter weight, divided case version of the LT85 was introduced in 1988 and used through 1991. The main short coming of the divided case version was its main and lay shaft bearings. The loading on the bearings in 5th gear caused frequent gearbox failure when cruising for long periods of time under high throttle. There was also a bearing quality problem at one stage of manufacture and the gearbox was sensitive to the type of oil used.
In 1991 the relationship between Rover and Santana ended and the LT85 was no longer available to Rover. They needed to find a quick short term solution while they developed a new stronger gearbox.


From here: Link


Jon

Originally Posted by isuzurover

C H T and a couple of others are already running R380s behind 4BD1Ts. One guy I know has broken a couple of R380s behind his, but NFI what suffix, his rangie weighs a tonne, he tends to be hard on his vehicles, and he has a custom steel bellhousing - may not be perfectly aligned.

My Isuzu 4BD1T/R380 have now done over 70000ks - most of it working hard in the bush. No problems whatsoever with the gearbox - it is a late suffix with the larger layshaft bearings. FWIW Ashcrofts said that the late suffix R380s are stronger than the LT85. I am very glad that I went the R380 route because the ratios with a 1.2:1 transfer case are perfectly suited to the engine.

I would advise anyone to use a late suffux R380 with the bell housing properly aligned.

C H T