Which gearbox oil grade

[astontr6]

1 hour ago, Drewmotty said:

20w/50 was specified for MGBs with overdrive gearboxes. I’d be interested to know who specified it and why. 

Cars built in the 50's and 60's, it was common that engine oil was specified for the gearbox by UK car manufacturers as the tooth form on the gear teeth was basic and engine output was low, putting it nicely. As the influence of US auto manufacturers became more evident by their advanced design and machine tool practices, they were taken up here. Which included new types of oil were developed. 

Bruce.

[Red6]

As always the responses are very interesting...

Not sure what the TR3/4/5 manuals say but as others point out Triumph's TR6 manual recommends SAE90/EP90. I assume that the Service Division of Triumph Motors British Leyland UK Limited fall into the category of "those that really know their stuff".

I am not sure why anyone would consider following 1950's and 1960's advice when the 1970's recommendation was different. I do however appreciate that more modern alternatives might exist but I for one will be sticking with EP 90.

[tr6tuga]

Sorry to come over, but

I just changed gearbox/ A type overdrive first atemp to find wy overdrive didn't engage after a gearbox support bracket change.

Used a of the shelf equivalent to EP 90, I was told, and issue not solved.

Check all eletrics and still not working as it should, no engagement 2,3 and 4

Order from moss dynolite 80w90 to check if there is any improvement

Nevertheless ,in between, when opening the fill plug, about 100cc came out as a burst, and stopped after a while.

Is this due to overpressure?

The magnetic drain plug had metal bits, is it too much ? difficult to say .

BB says to click 6 times the overdrive switch to ease out the pressure, does it makes sense?

Next time try to clean the bottom filter, difficult task under a jackup Tr.

Advice of tasks sequence required please

Thank you 

 

[michaelfinnis]

8 hours ago, RogerH said:

Hi Mike,

Which Original Workshop manual - TR2, 3, 3A, 4, 4A 5 or 6

The early cars specified non-EP oils due to the yellow metals.

The TR4A did specify EP  But a GL4 should be used.

I don't think engine oil was ever specified. Can you have a 20/50 non engine oil.!!!

 

Roger 

Hi Roger,

Sorry, should have clarified,I was referring to the TR6 manual, can’t speak for the earlier cars. As you say GL4 spec.

Mike.

[astontr6]

16 hours ago, tr6tuga said:

Sorry to come over, but

I just changed gearbox/ A type overdrive first atemp to find wy overdrive didn't engage after a gearbox support bracket change.

Used a of the shelf equivalent to EP 90, I was told, and issue not solved.

Check all eletrics and still not working as it should, no engagement 2,3 and 4

Order from moss dynolite 80w90 to check if there is any improvement

Nevertheless ,in between, when opening the fill plug, about 100cc came out as a burst, and stopped after a while.

Is this due to overpressure?

The magnetic drain plug had metal bits, is it too much ? difficult to say .

BB says to click 6 times the overdrive switch to ease out the pressure, does it makes sense?

Next time try to clean the bottom filter, difficult task under a jackup Tr.

Advice of tasks sequence required please

Thank you 

 

Have you had engine oil in your G/B?

Bruce.

[tr6tuga]

Not that I am aware, is that possible?

It smells different!

[astontr6]

1 hour ago, tr6tuga said:

Not that I am aware, is that possible?

It smells different!

A few years ago, there were a number of people on this Forum who were promoting its use as against hypoid. But i know two TRer's who followed this advice and their O/D's stopped working with the oil ways blocked by a white froth because the engine oil was breaking down as It was exposed to very high pressures. Thats why if you use engine oil it has to be the one suitable for an Austin/ Morris mini!!! which has a hypoid base additive in it to stop this happening. Was this the reason that Hypoid was recommended by BL for their G/B & O/D. I have used Hypoid 80/90 for nearly 50 years without any trouble.

Bruce.