R380 bearbox, how is it different?

**JDNSW** · 18th October 2006, 11:28 AM

Originally Posted by scrambler

Correct me if I'm wrong here, but reading around the impression I got of strength in gearboxes was that Series 1 was pretty dodgy, Series 2 ok, 2a tough, 3 quite a bit weaker, LT95 (Range Rover and V8 or Isuzu diesel 1980-1985) seriously tough (and stronger again in LT95a with the Army), LT85 5-speed (1985 - 1990? - "the Spanish box") a bit behind that, LT77 little better than a Series 3 and R380 pretty close to the LT95. The big problem with the LT95 is that it's only a 4 speed, so of the 5 speed boxes, R380 wins hands down.

The history of these boxes is interesting - the R380 is a re-engineered derivative of the LT77, which was originally a Jaguar gearbox never designed for off-road stresses. What the Series 3 box's excuse is I don't know. The numbers after LT refer to the distance between the input and output shafts, in mm. R380 stands for "Rated to 380Nm of torque."

Any comments from people who've broken any or all of those?

The Series 1 box I have heard was a Rover box introduced in 1932. Obviously not designed for offroad use, it coped with the 1.6 and 2litre engines without a great deal of drama and with minor changes. However, the more powerful engine introduced with the Series 2 showed up shortcomings and it was beefed up for Series 2a including two changes to the layshaft. With these changes it coped well with the six and the diesel, as well as the petrol engine.
The Series 3 box, introduced for very late 2a station wagons (although I doubt any found their way to Australia - I think only home market), provided synchromesh on all forward gears. But this had to be fitted into the same dimensions, and a few weaknesses showed up as a result - it was basically the same design with synchromesh shoehorned in.
The LT95, although used in the Rangerover, was designed to meet the requirements of the 101 gun tractor, and is very robust as others have commented. But only has four gears.
Of course, it is often forgotten that cars almost never had more than four gears until about 1970, and for most of the motoring era up to then (say from 1900 on) three gears were the norm except for low powered cars in the UK and a few sporting and luxury cars elsewhere, plus a few French, Italian and German cars. And up to the mid twenties the best selling car of all worldwide had only two gears. And Landcruisers only introduced four gears in about 1970 - before that they were three gear.
You have to wonder why we seem to think more gears are necessary, particularly since the torque band of most engines is a lot better than it was thirty or forty years ago.
John

**scrambler** · 18th October 2006, 11:37 AM

I'm with you on the number of gears, JD. I went looking for a 4 speed County - didn't want the update 5 speed. I guess it allows finer tuning of gear slection, but not essential esp. when weaker design. Even with the 4 speed I'm not sure 1st is required for on-road use.

Steve

**JDNSW** · 18th October 2006, 12:07 PM

Originally Posted by scrambler

I'm with you on the number of gears, JD. I went looking for a 4 speed County - didn't want the update 5 speed. I guess it allows finer tuning of gear slection, but not essential esp. when weaker design. Even with the 4 speed I'm not sure 1st is required for on-road use.

Steve

Yes, at the time I did not know much about the various gearboxes fitted to 110s, but I was advised to look for a four speed when I was after the County, and I am glad I did so. Only work needed on the box in over 400,000km has been to replace the input bearing (but replaced all the bearings and seals of course when it was in bits). I agree you can get away without first except uphill or heavily loaded, but using it will extend clutch life.
John

**Bush65** · 18th October 2006, 04:54 PM

Originally Posted by Omaroo

Well, after only 180,000 relatively easy kilometres, my R380 is now in need of an $2,200 rebuild. It started making slight tapping noises on down-shift, particularly into second before going around a roundabout.

It appears that second and reverse are adjacent on the shaft, and their is a shim washer at the end of the shaft that has disintegrated - allowing the shaft, and the gear set to move.

Bugger! - new bearings all round, clutch replace while we're at it and possibly a dual-mass flywheel, and removal/re-install. All up? well over 3 G's and probably closer to 4. I really expected longer life from my Defender.

In the R380, reverse was moved into the extension housing, alongside 5th. That is how reverse came to have syncromesh.

I assume they moved it there to be able to increase the width of the gears for increased strength over the LT77.

**Blknight.aus** · 18th October 2006, 05:05 PM

not to insinuate anything but if the thrust washer got that dead then you have had lube problems for one reason or another... make sure to check the pump in the box for blockage when you do the rebuild and dont let any idiot put 80/90 in it, your just going to wind up needing new syncros and bearings (particularly the thrusts) before they're due

**Frenchie** · 18th October 2006, 05:05 PM

Originally Posted by scrambler

I'm with you on the number of gears, JD. I went looking for a 4 speed County - didn't want the update 5 speed. I guess it allows finer tuning of gear slection, but not essential esp. when weaker design. Even with the 4 speed I'm not sure 1st is required for on-road use.

Steve

My V8 County was 4-speed, loved it, never used 1st on road unless towing.

roadkill · 18th October 2006, 08:36 PM

W O W !!!!!!!!!!
Ask a question, get a heap of answers!

Im really impressed with this site, the people that use it, and the info that one can get in a reliatvely short time frame.

Thank you all for restoring my faith in the trusty landy

Its why i bought my next one.

This makes 4 now, the others have been ...ummmm....less than freindly, but this defender thingy, it feels great!

Cheers again

**isuzurover** · 19th October 2006, 12:18 PM

According to Dave Ashcroft, the Late Suffix R380s are as strong or stronger than the LT85 5-speed.

I am not sure about that, but I know I am perfectly happy with the LT85 in my 110 county (3.9D) - and wouldn"t want a 4-speed. My particular box lasted until 260,000km when it was rebuilt by Mal Story. I fully expect it to last at least another 300,000km. Even with the turbo that will be going in soon.

I have driven both (4spd and 5spd) countys and it would be very hard to go back to a 4spd as a touring vehicle.

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