Gearbox lt77?

[unstable load]

If you want a really bulletproof box, and a real challenge finding it, look for a R380 2 wheel drive box.....
There are plenty around in 4X4 guise, but 4X2 is really hard to find.

 

[Baron von Marlon]

The only problem I had with an LT77 was on my TR7. Internal oil pump failed while doing 80 on the M25 late one night. Car getting slower and slower until I could make it to Clacket's lane services. Then ground to a halt. Apparently the fibre gears wear and fail.

They do, yes. Steel gears are now available as an upgrade, which I've put in every one I've rebuilt.

 

[roverp480]

Often the reason the oil pump fails is using an oil which is too thick especially when cold. It will strip if something like EP80 is used instead of the correct spec.

 

[mtb_tuli]

Thanks all, yes it´s a 4 cyl. Triumph TR7. Anyway, the combination LT77 plus V8 bellhousing is nearly impossible to find here, so I will have to start looking for a bellhousing next.
The gearlever remote is there, but the guy wants to sell it for extra money...

 

[Baron von Marlon]

Often the reason the oil pump fails is using an oil which is too thick especially when cold. It will strip if something like EP80 is used instead of the correct spec.

The best way round that is to fit the upgraded steel oil pump gears and use a 75w90 synthetic gear oil in it. That's what I've done with mine (Motul Gear 300) and, whilst the 1st to 2nd change has to be taken slowly when very cold, within a few minutes it's warm enough to change normally and all other gear changes are like a knife through butter.

BL changed the recommended oil to ATF after complaints about the 1st-2nd shift when cold, but ATF isn't the best thing for the gears and bearings in the transmission. In my mind it's worth putting up with a slightly crunchy change when cold, for enhanced transmission life.

 

[mtb_tuli]

Maybe this is helpful. Found information on a site from a well experienced Morgan dealer here in Germany, the made tests with various oils on the LT 77. They explain exactly, what Martin says and experienced.
Finally they tried "Difflock Evolution 1", a fully synthetic gear oil from the UK and expensive...
With this oil, they experienced the best performance with a cold box.

 

[sdibbers]

They do, yes. Steel gears are now available as an upgrade, which I've put in every one I've rebuilt.

IIRC mine was running with ATF for oil. Later TR7's came from the factory with ATF instead of SAE20 oil that the earlier cars had. It did improve gear shift quality for the better.