Gearbox oil.

Post by **sonic23** » 18 Oct 2006, 13:50

I was told by the local motor factor that any 80w90 gearbox oil was suitable for the Syncro, however on closer inspection of what they had it was GL5 80W90. So I left it.

He couldn't explain the difference between GL5 and GL4 - though insisted they were all the same.

I take it i made the right decision by not buying it?.

Interesetingly, I then went to GSF - and they just had Morris 80w90 and couldn't tell me if it's GL4 or 5. So I didn't buy that.

Anyone know if the GSF oil is ok?

cheers,
Rich

Post by **toomanytoys** » 18 Oct 2006, 14:05

2 theories on this..
Dont use the GL5 stuff as it will disolve the "white metal" bearings/bushes in the box...
In reality, this is only a problem if the oil gets hotter than approx 100 degC (going on what some american guys have done with Unimog 404 gearboxes)
If a syncro box can heat the oil up that far... then it possibly is a problem..

The other theory is that as long as there is good oil in there, it will be ok..
I have run Comma SX semi synth GL5 gear oil in my 2wd 5 speed for 7 years.. the thing has done loads of miles (100k) at high speed.. sure it leaks a little, but thats coz as far as I can tell its done 200k miles+..

IIRC Harryman has the same oil in his syncro...

My current (borrowed) box has Redline MT90....

Post by **sonic23** » 18 Oct 2006, 17:46

I've got some of the following ordered. Looks like it could be just the thing.

http://www.difflock.com/cgi-bin/wm10/wm ... item=DF457

Post by **Russel** » 18 Oct 2006, 19:13

The oil in a syncro box on a hot day(yes even in the Uk) can exeed
100 gegrees on a long run.

Post by **toomanytoys** » 19 Oct 2006, 07:28

Cheers Russel

Just need to see if we can actually de bunk this "corrosion" problem.. maybe it was early gear oils that caused the problems..

Post by **HarryMann** » 19 Oct 2006, 15:57

IIRC Harryman has the same oil in his syncro...

he does, and for the cost the Comma SX semi-synth seems the easy answer, might as well take no chances with a GL-5.

Can't help with the debunking,but imagine it would take a long time to dissolve, but have heard the odd gorror story on US forums about white metal/bronze in oil(whether exagerrated or true)

Post by **toomanytoys** » 20 Oct 2006, 17:59

Er Clive.. Comma SX semi syth IS GL5.........

Post by **HarryMann** » 20 Oct 2006, 18:31

BUt I think that semi-synth GL-5s don't need th additives that dino GL-5s need to reach that spec - my understanding anyway

Post by **HarryMann** » 20 Oct 2006, 18:32

But I think that semi-synth GL-5s don't need the same (corrosive) additives that dino GL-5s need to reach that spec - my understanding anyway

Post by **HarryMann** » 20 Oct 2006, 19:12

I think it's worth saying that if you are in a spot, and can only get GL-5 for a while, we're pretty sure it won't do any harm in the short term, till you can drain and change it - is that about right?

Prob. better than running oil full of metal, be it bronze or steel, and definitely better than running a low oil level

Post by **stuckin88** » 24 Oct 2006, 16:50

according to Comma website their semi synth gear oil is available in both GL4 & 5 --Redline MT90 makes a big difference-I found--for the £50 odd it cost to fill the gearbox it stopped the crunching 2nd gear & made the changes far smoother--didnt make the gearbox last any longer tho--

Post by **HarryMann** » 24 Oct 2006, 22:37

it stopped the crunching 2nd gear & made the changes far smoother--didnt make the gearbox last any longer tho--

you mean it didn't stop it failing eventually! I agree its good stuff (I could only get MTL), but suppose if it was damaged already then no oil could stop that eventuality.

Post by **toomanytoys** » 25 Oct 2006, 06:50

Yeah, but just changing to Comma SX made a huge difference to my 2wd box.. that was 7 years ago and its done at least 100k hard miles since.... (+ an extra oil change change)

Post by **sonic23** » 25 Oct 2006, 08:11

Has anyone tried out the stuff that I've ordered from the DiffLock shop?

Classic GL4 Gear Oil 80W90

I don't want to put it in my spanking recon'd box if it's the wrong stuff.