advice on gearbox oil please

[jim.2007]

To cut a long storey short i am on my fourth lt77 gearbox in an early chim, the 4th gearbox has now been uprated with the layshaft and bearings so hopefully it won't go bang again(if it does i'll be sectioned i think..!)
Any way, my problem now is when the car is cold the gears are very notchy, i have to tootle about untill the oil gets warm in the gearbox before i can get a slick gearchange from 4th to third and 3rd to second( when its warm no probs at all) I have spoke to a couple of people who said this is normal with the lt77, PAS fluid is the oil used but i was wondering of changing to a thinner fluid to see if this would solve the problem? but then, will it be up to the job when its at full temperature? Does anyone know of a synthetic oil that maybe gives the best of both worlds?

[heightswitch]

jim.2007 said:

To cut a long storey short i am on my fourth lt77 gearbox in an early chim, the 4th gearbox has now been uprated with the layshaft and bearings so hopefully it won't go bang again(if it does i'll be sectioned i think..!)
Any way, my problem now is when the car is cold the gears are very notchy, i have to tootle about untill the oil gets warm in the gearbox before i can get a slick gearchange from 4th to third and 3rd to second( when its warm no probs at all) I have spoke to a couple of people who said this is normal with the lt77, PAS fluid is the oil used but i was wondering of changing to a thinner fluid to see if this would solve the problem? but then, will it be up to the job when its at full temperature? Does anyone know of a synthetic oil that maybe gives the best of both worlds?

This is usual but so is selector pin and shaft wear in the gear change mechanism. There are lots of little roll pins etc that are known to wear causing change issues. When you say 4th box do you mean 4th second hand box or have you had the unit properly re-built? buying worn ex landy boxes and then shoving 275hp through them generally does give selector and baulky change issues.

N.

[jim.2007]

4th rebuilt with gaurentee..court action was threatened to get the fourth one done..this one is 3 weeks old

[heightswitch]

jim.2007 said:

4th rebuilt with gaurentee..court action was threatened to get the fourth one done..this one is 3 weeks old

The box is known to be a little notchy when cold Jim and from memory the 3rd - 2nd shift is the worst affected. you can use transmission oil of different grades but in a newly re-conned box I would want a good oil that won't thin too excessively when warm.

it may also be that you need to knock a few teeth off here and there jim. I would run for 200 miles then drop the oil and flush, then run for 1000 miles and change the oil again. it could be that everything is just tight and in mesh.

N.

[pwd95]

Castrol SMX-S. Just done it, great stuff

[Number 7]

pwd95 said:

Castrol SMX-S. Just done it, great stuff

Ditto.

IIRC ATF was only specified to avoid the cold crunch effect, without much thought for how the box would wear.

With SMS you still need to do the first straight to third on cold days until it's all warmed up.

7.

[jim.2007]

will do that, off for a run tommorow that will bring me up to the 200 miles, what's this smx stuff? who made bye ? good stuff?

[Number 7]

http://www.opieoils.co.uk/popup.aspx?src=%2fwolthu...


7.

[jim.2007]

whats the cold crunch effect! so i'm not the only one one who nearly ended up in a mental instatute!
The money ive paid could of got a T5 but want to keep the ratios as its more exiting than the T5!

[350Matt]

jim.2007 said:

will do that, off for a run tommorow that will bring me up to the 200 miles, what's this smx stuff? who made bye ? good stuff?

Your local Halfords may sell it

its a castrol oil, pricey at £6 / litre but how often do you change gear oil? plus its far far better for the box than ATF