Gearbox oil - LT77

kiwicar · Post by **kiwicar** » Fri Jul 11, 2008 3:33 pm

I have a concern about Molibdimum disulphide in anything with a roller or ball bearing. You add molly to anything with a sliding bearing surface (plain bearings gears slip rings etc) because the Moyibdimum disulphide has a spherical structure (and is increadibly heard) and acts as many thousands of small ball bearings.
This is good in this situation.
However put these very hard spheres into a roller bearing or ball bearing and you have a problem. The spheres are very small relative to the rollers of the bearing and owing to the rolling action of this type of bearing, the rolling ellement will crush down onto these spheres with two results,
1/ the spheres build up infont of the rolling surface causing the rolling action to stall and the bearing to skid.
2/ The spheres tend to get embedded in the surface of the rolling surface causing the surface of both the race and the rolling element to become pitted, this leads very rapidly to the hardened surface shattering which is not good!
Sorry to drone on about rolling ellement bearings and molly slip but it was 1/3 of my brother's PHD thesis and some of the test rig bearings were worth seeing!
Mike

ramon alban · Post by **ramon alban** » Fri Jul 11, 2008 9:54 pm

thev8kid wrote:can i drain this and use the mobil1 and mollyslip etc, or will it be too thin for the pump?

Tony, my experiences are with rhe LT77 as fitted to the SD1 Vitesse and I advocate the cleaning and lubrication process recommended on my website as being nothing short of spectacular.

If the sherpa box is fundamentally the same then I dont see a problem, because a pump capable of shifting thin ATF will cetainly handle Mobil 1 0w40 viscosity.

As for the molyslip issue, if top oil industry scientists say "no way jose" then so be it.

But a university degree thesis is a very singular finding.

If molyslip has wrecked my LT77 then it has a funny way of defying damage. - its still running perfect.

Post by **Coops** » Fri Jul 11, 2008 11:27 pm

my box aint got ATF in thats what im saying

its got the thicker gear oil in, so will it pump the mobil 1 around ok as its thinner than the gear oil,

bodger · Post by **bodger** » Sat Jul 12, 2008 12:37 am

stick with ATF mate , that whats recomended in all of those boxes

have you stripped the box yet ? , i just wonder there must be a reason that the thicker oil was put in
and if it's been run with it there could be a problem with the oil pump ,
the cheapest place i have found is Royce Power Transmission Ltd , harlow
for the oil pump set , they do the bearings and gaskets too , very cheap
which for the sake of about 12 quid is worth changing anyway
and the bearing that suffers is the first motion one ( see my picture )

Post by **Coops** » Sat Jul 12, 2008 12:51 am

this oil has been used since day one in my box mate,
and 4yrs down the line still using the same grade.

kiwicar · Post by **kiwicar** » Sat Jul 12, 2008 6:59 am

Ramon
so an oil company selling a product takes a more indipendent view of on issue than a docterate research project intended to find out why bearings are failing when used with an oil addative does it?

Keep reading the glossy brochures.
I would just remind you of how many vauxhall engines were changed a few years ago by shell when they changed the fuel blend without testing it properly (and the nickersill liner issue more recently) the importent thing to oil companies is selling oil, just compare their R&D budgets with their marketing budgets.
Tony I would stick with good quality oil recomended by the box manufacturer and avoid addatives that are not recomended by them.
Mike
said my piece will leave it here

ramon alban · Post by **ramon alban** » Sat Jul 12, 2008 8:20 pm

thev8kid wrote:my box aint got ATF in thats what im saying
its got the thicker gear oil in, so will it pump the mobil 1 around ok as its thinner than the gear oil,

Hello Tony, You will need to establish if your Sherpa box has the same pump spec as the SD1 LT77 Box, if so, then the answer is Yes, as it was originally capable of pushing ATF of similar viscosity.

According to Mike you need to avoid Molyslip and Bodger says use ATF, and their points of view may be more valid for your application. You pays yer money, etc.

You are not in the position that I was, circa 1995, when I was about to junk the LT77 because it was too unfriendly but by experimenting with Mobil 1 and Molyslip based on the recommendation of a Mobil Oil employee who also ran SD1's, I coaxed a minimum of 13 extra years from the gearbox and it's still going OK. For me that was a result.

ramon alban · Post by **ramon alban** » Sat Jul 12, 2008 8:39 pm

kiwicar wrote:Ramon
so an oil company selling a product takes a more indipendent view of on issue than a docterate research project intended to find out why bearings are failing when used with an oil addative does it?
Keep reading the glossy brochures.
I would just remind you of how many vauxhall engines were changed a few years ago by shell when they changed the fuel blend without testing it properly (and the nickersill liner issue more recently) the importent thing to oil companies is selling oil, just compare their R&D budgets with their marketing budgets.
Tony I would stick with good quality oil recomended by the box manufacturer and avoid addatives that are not recomended by them.
Mike
said my piece will leave it here

Hello Mike, I do not intend to belittle your brother's findings but you did mis-represent what I said.

quote "As for the molyslip issue, if top oil industry scientists say "no way jose" then so be it"

To clarify - If the oil industry are saying DONT use Molyslip, etc. then so be it - ie dont use it.

I did not say "the oil industry advocates the use of molyslip".

There is no conflict here.

kstrutt1 · Post by **kstrutt1** » Tue Jul 15, 2008 3:10 pm

I have been using the Oil Ford sell for the type 9 gearbox in my TR7 (now TR8) for many years now, the original box covered 160,000 miles and was only suffering from worn synchros when removed.

I believe it is a ATF base with some sort of adative pack.

Kevin

Post by **Coops** » Thu Jul 17, 2008 7:50 pm

ramon alban wrote:
thev8kid wrote:my box aint got ATF in thats what im saying
its got the thicker gear oil in, so will it pump the mobil 1 around ok as its thinner than the gear oil,
Hello Tony, You will need to establish if your Sherpa box has the same pump spec as the SD1 LT77 Box, if so, then the answer is Yes, as it was originally capable of pushing ATF of similar viscosity.

According to Mike you need to avoid Molyslip and Bodger says use ATF, and their points of view may be more valid for your application. You pays yer money, etc.

You are not in the position that I was, circa 1995, when I was about to junk the LT77 because it was too unfriendly but by experimenting with Mobil 1 and Molyslip based on the recommendation of a Mobil Oil employee who also ran SD1's, I coaxed a minimum of 13 extra years from the gearbox and it's still going OK. For me that was a result.

your going to tell me to check this i need to strip the box aint you.
and i have no time to have the car laid up again at present,
so looks like its going to have to wait for now

ramon alban · Post by **ramon alban** » Thu Jul 17, 2008 10:46 pm

thev8kid wrote:
your going to tell me to check this i need to strip the box aint you.
and i have no time to have the car laid up again at present,
so looks like its going to have to wait for now

Hello Tony,

Not at all. The only reason I am cautious is because I am not familiar with the Sherpa box spec. and at the end of the day you have to decide what you need.

Personally I think it a reasonable assumption that the pump in your Sherpa box would adequately push Mobil 1 0w40 around quite happily.

If you are not prepared to assume the same, then status quo rules.

But if you think the anecdotal results that I and others have experienced worth trying for and if you fancy a friendly box with no vices, pop in a couple of litres of Mobil 1 or Castrol RS and give it a go for a few weeks.

Regarding the Molyslip thing, its already been debated so there it little more to add other than, it worked fine in my box and differential for 13 years.

Pitschi · Post by **Pitschi** » Wed May 12, 2010 2:27 pm

Ramon,

is it this stuff?

http://cgi.ebay.de/Molyslip-Gearbox-Pro ... 2306e0fec0

or

http://cgi.ebay.co.uk/MOLYSLIP-2001-G-G ... 414da29728

or anything else?

Cheers
Pitschi

ramon alban · Post by **ramon alban** » Wed May 12, 2010 9:14 pm

Hello Pitschi

This is what I use

from

http://www.wilcodirect.co.uk/index.php? ... ts_id=1202

or

http://www.halfords.com/webapp/wcs/stor ... yId_165750

Dunno about other products, one would need to experiment as I did - the first one I tried worked OK.

Hope this helps

Pitschi · Post by **Pitschi** » Fri May 14, 2010 7:19 am

Thanks,

found out that the purple version is just a newer packaging.

Cheers
Pitschi