Thread: R380 Another Failure, What to do...?

I wanted to start a different thread to R380 Failure!, as I didn't want to hijack it, but the theme is essentially the same.

We have a S1 Disco 300TDi. The gearbox failed a year or so ago (55A**_*L). We replaced it with a secondhand unit, which gave it another 6 months, when it failed also. Both boxes have direct drive, but nothing through the layshaft. I wanted to repair the later, suffix L box, as it was fitted as a new, not reco, unit by Fred Smith. We puled it down yesterday to find the layshaft and input shaft were destroyed.


So, a simple fix is not in order. The rest of the box appears fine, with minimal wear to bearings, synchro cones etc



OK, obviously the layshaft and input shafts here are, well, relaxed. So to speak. So, where to? We have a R380 from a V8 Rangie. Unknown quantity, but was apparently a goer. This is a 53A, suffix E box.
two questions: Will it fit in as a temporary measure?, could I cannibalise it for the shafts to repair the Suffix L? Or, third question, are the shafts affordable? Budget is a strong consideration in this case.

Originally Posted by wrinklearthur

Thanks Dennis
I can now put this failure into a different light.
So does the gear oil aerate when the box is worked hard and long up steep slopes?

Your explanation does fit with what my vehicle was doing at the time that it's gearbox started to become noisy.
I was pulling a heavy loaded trailer up a long steep slope, in second gear high range pulling hard with the engine running fast for a quarter of an hour.
My defender hasn't a oil cooler for the gearbox and after that climb, I did stop and the oil smell was quite strong of gearbox oil.
After I had arrived home I checked the level and it was down a little, but only needed half a pint to top it up, the transfer level was still the same and both boxes didn't have any leaks.

My pull down of that box had better take place sooner so I can pass the info of what I have found on.

On the to do list now ,is to fit a 'L' suffix box, oil cooler, temperature sender and temperature gauge.

WRINKLE AURTHER
I suppose I have to ask what fluid/oil were you running in the box before it failed?

The damage is lubrication breakdown for sure and having spent a previous life in the trucking business at factory level, I have seen it countles time before.

Yes you can get foaming although it would be more prevalent with EP oils like 80/90 weights than the prescribed Dexron trans fluids for that application. Unless you had a mix in the box--oils and fluids don't do too well!

For info the box is sealed by a sleeve on the mainshaft aft of the OD/Rev gear pack which is immediately in front of the t/case. The forward seal on the t/case also runs on the same sleeve in a back to back situation and there is a drain groove cut into that sleeve to allow oil to drain away.
Hence the gearbox and the T/case are lubed seperately

It doesn't take much for the seal to go down especially if you are running high temps like 300dgf where upon the oil would then start to oxidize & drip out of the vent at the back of the box reducing the oil/fluid level /lube quality in the gearbox maincase.

There is a little oil pump on the back of the layshaft (countershaft) to pump fluid forward but once gear debris gets flying about it plugs up the barrel strainer, then things really start tearing themselves apart and unglued.
Even the rear mainshaft bearing is a plastic cage affair and when temps get very high the bearing has a tendency to fall part and the oil flows out in any case

Yes I think you might need to consider a cooler on the box and the use of a synthetic oil/fluid if you are doing some arduous stuff, I see Redline mentioned. Yes good stuff, but you might want to call a specialist oil company for some advise on what is available on your side down under.

Out of interest when the truck failed what were the ambients.
The two units I repaired which quit and came in on the hook, off the mountain range.
One was spring time so it would have been cool, but the last one towing a camping trailer was in the height of summer--read hot!

Obviously a spendy repair!
My suggestion would be to be a bit pro active after re-instatement and get a cheapy infrared thermometer and shoot the temps on the maincase plus in the in and out of the cooler if you get one installed during a road test pulling a load .
Obviously look for oil spots on the ground to make sure you have no leakage--(Yes I know its a LR and leaks come with the territory)
Hope that helps and if you have more questions just fire away mate.

Cheers Dennis
zedcars