Thread: Another R380 gearbox problem

Ahhr so someone could make out the audio file I posted ;-)

In response to the oil statement - I thought the Manual gearbox is best suited to a ATF lubrication oil (Fuchs is good), these are usually a redy colour.

I know this isn't much help though.

chosen

I'm guessing a grumble in 4th/5th would be a mainshaft bearing worn.

err, haven't you fella's seen the many threads on R380's and oils ? It's been an ongoing online debate for years.

Bottom line is that originally ATF Dex II was specified, then in '97 a TSB was issued overiding this and specifying Caltex MTF94, a 75w-80, 10.5cSt@100 manual trans fluid.
You can use any light manual gear oil you want, but some provide better protection than others, some drivers (and gearboxes) seem to prefer one blend over another. Some still prefer to use ATF, but I'd rather the better gear/bearing protection of a dedicated manual trans fluid.

Here's a link to a spec chart of light gear oils suitable. http://members.shaw.ca/jbarge/MTF.htm
Bear in mind a few blokes on here have also used a light 75w-90 manual gear oil (14.5 cSt @ 100*C, eg Redline MT90, Castrol Syntrax) with good success too. I've found that most 75w-80/85's thin out far too much in the heat of summer, resulting in a ratly gearbox and notchy changing.

I wouldn't use an additive of any description, they are junk IMO. A few on here use them, but I can't follow the logic. My thinking goes that if your oil isn't doing the job, buy a better one, usually full synthetic that has been fully formulated by a bloke (usually with a Phd) who knows what he's doing. The additive packages in oils account for up to 25% of the oils volume (at least in engine oils) and are pretty complex and balanced. Who knows what an xyz super slick additive may or may not do, and they are usually filled with some pretty cheap Group I mineral oil as a carrier.

Heavier gear oil in the t/case is OK, even though 75w-90, 80w-90 or straight SAE90 is specified. It can't do any harm, and as one oil blender I've corresponded with in the US states, gears do last longer on heavier oils.
I'm running heavier there, as are a few others on here. When I had the t/case out a few weeks back, there was absolutely no wear on the dreaded g/box output shaft-t/case input gear spline at all. Vehicle has done 225,000km. I'm putting that mostly down to the cross drilled gear, but I do know one prominent Land Rover workshop in WA use only Redline Heavy Weight Shockproof in LT230's to prevent this wear. My current brew is 1l Syntrax, the balance SAF-XA (80w-140) and has been for a while.

Do a SEARCH on previous discussions as Rick suggested.

I haven't pulled apart an R380, but I have rebuilt an LT77. These gearboxes have an oil pump in them and fine oil galleries that deliver the oil to the gears. There are a lot of needle roller bearings, that don't take a lot of driving force, but help things to move along smoothly, and these need the pumped oil. Hence the need for a thinner oil.

Personally I use the Penrite Synthetic ATF because I found the Light Gear Oil too heavy in my case (others are happy with it) and because the Synthetic is much more stable at high temps.

I don't have as good an understanding of the tech side as Rick has, but I ask a lot of questions from those that do.

Spend an hour or two doing the search & reading opinions, before you go adding stuff to the gearbox. That'll save you time & money.

Some time ago, on Rick's recommendation, I changed to Redline MT90.

The changes & box operation since then have been extremely satisfactory, so much so, when changing down, I tend to lightly grab the centre of the stick length & push the gears in from that position. It moves very easily & smooth & I am pleased I changed oils. Was ATF.






NB. I am not related to rick, nor receive monies nor have any business interests with him.

I read all the R380 gearbox threads I could find before Ichanged all the oils, and the Castrol VMX was the one oil that most people in Queensland were recommending, likewise the couple of service guys I talked to recommended it. 85W/90 was the recommended diff and T/C oil as well. I'll change to a 85W140 on the weekend, and check the gearbox oil plug for any contaminates, and them re-fill with new VMX80.

So, if the grumble noise is the main-shaft bearing, is it likely to be terminal in a few hundred km, or is it something you just put up with until it gets worse? How difficult is it to change out the main-shaft bearing ( I've never done a gearbox before, but have rebuilt plenty of engines from Ford 4 and V6's, Chevy V8 right up to a Jaguar V12)