Thread: R380 Gearbox Oil Cooler

hope this is not against any sales rules on this site but pm me if you want a original Td5 defender unit.
Dennis

as a rough guidline

DEX III compliant ATF starts to drop the bundle at about 160 deg C and is done and dusted by about 300

s_b, no cooler, but my point was if it gets that hot that quickly under bugger all load, well, you get the idea

Jon, in my g/box I used to find that while the good quality 75W-80 and 85 syn based oils like Redline MTL and Castrol Syntrans are fine at elevated temps, gear and bearing rattle and synchro action goes to hell (baulking) as they thin out.

This was at ambients of about 35*C and above.

I now run Motul Gear 300 (75W-90, around 15cSt @100*C) and this copes well in summer with good winter shiftability. (it only gets down to -5* or so here)
Obviously the oil cooler (which I have and have never fitted) is the real fix.

Originally Posted by rick130

s_b, no cooler, but my point was if it gets that hot that quickly under bugger all load, well, you get the idea

Jon, in my g/box I used to find that while the good quality 75W-80 and 85 syn based oils like Redline MTL and Castrol Syntrans are fine at elevated temps, gear and bearing rattle and synchro action goes to hell (baulking) as they thin out.

This was at ambients of about 35*C and above.

I now run Motul Gear 300 (75W-90, around 15cSt @100*C) and this copes well in summer with good winter shiftability. (it only gets down to -5* or so here)
Obviously the oil cooler (which I have and have never fitted) is the real fix.

Thanks.

The only time I have had the gbox smell like it was hot was when the input gear to lay gear decided to crounch each other. So don't know what came first the thin oil or if the destruction of the gears generated the heat in the first place. This was after approx 90 min 100-110 km/h run down the Hume in 5th. Not towing but a few kg of LR wheels and a pedestal drill.

I would prefer to have a cooler than have to rebuild the gbox again, again. I will have to rebuild it as my mechanic says the gbox talks to him, a few whining sounds as you go into various gears and particularly on overrun. I'd like to build a reliable box but I suspect that one of "the grubb's" MSA boxes might be overkill behind the 300Tdi.

Hi Guys/Gals,
We towed a van up to QLD from Tas. last year with our 300tdi 94 130 dual cab, and the transmission tunnel got that hot we needed the aircon on to keep cool, even though it was only 17 degrees outside. Eight months later I am putting in a new gearbox (L suffix) from ashcroft. Not a cheap exercise. Going in the car at the same time is a 97 r380 oil cooler out of a disco, it is a proper cooler about 500mm x 60mm x 90mm, I will have to modify the piping but it will be worth it.
Cheers
Angus

Would heat sinks mounted along the cooler pipe make any difference?

Originally Posted by bambusa

Would heat sinks mounted along the cooler pipe make any difference?

yes that is what a cooler is a big heatsink that also increases the surface area to the air to exchange the heat from the oil to the cooler and then to the air.

If you want to put a cooler onto your R380 go to the LR site where they are getting rid of the excess spares, I got a thermostatic cover that goes on the side of the Gbox. It wasn't cheap but better than the new price from the UK.