Welcome to our resource for MG Car Information.



TR parts and Triumph parts, TR bits, Triumph Car Spares and accessories are available for TR2, TR3, TR3A, TR4, TR4A, TR5, TR6, TR7, TR8, Spitfire and Stag and other TR models are available from British car spares and parts company LBCarCo.

Triumph TR6 - overdrive oil?

Which is the best oil to use? 30non- detergent,20w50 or gl-4 80?

I have used Valvoline 20W50 R (the R is for Racing) for the last 16 years (94,000 miles) in my gearbox with overdrive and I'm satisfied with it. BTW, the specs. for this oil quote that it has double the Zinc and Phosphorus needed for flat tappet engines etc. where high contact pressures occur like in a gear box.

I buy it at Car Quest.
Don Elliott

Interesting. The handbook specifies SAE 90 for gearbox, overdrive and final drive.

B.J. Quartermaine

And the overdrive specialist Quantumechanics recommends SAE 30 straight Non-Detergent as was produced in 1955.

He explains why you should not use 90 Hypoid. He makes no reference to high pressure contact points on the faces of the gear teeth which need additives like those found in Valvoline 20W50.

In the first 80,250 miles with my TR3A, I ruined the gears 3 times in the gearbox using SAE 30 non-detergent as was reccomended in the Triumph manual at that time. In over 94,000 miles since then, the gear wear is as expected.

Don Elliott, Original Owner, Montreal, Canada

Don Elliott

If you want to spend over $2000 to have your overdrive rebuilt, then by all means use 80 or 90 wt. gearoil. Ask me how I know.
J Salbego

Don, How did you know to use Valvoline 20w50?
J Salbego

When I was doing my total body-off restoration from 1987 to 1990, I came to the point when I was ready to fill the gearbox/overdrive with oil so I asked Ken Gillanders, a good friend who runs British Frame and Engine in Temple City, California. He raced and dragged his TR2 back in the 1950s and was featured with his 1980 TR8 in the recent "Triumph World". He told me to use Valvoline 20W50 - but make sure to use the "R" for Racing designation. I countered with all the usual things I knew about, like the detergent is too slippery and the cone clutch will slip, etc. Won't it foam which would make a problem too ?

He convinced me with his answers and told me to go ahead and use it. He had been using it for several years back in 1990.

I have been a member of the Triumph Register of So. Cal since 1987 and I followed Ken's advice. It was good advice.

Don Elliott

Good to hear your "voice". Hope you had a good winter.
Have you confirmed with Valvoline that there is STILL ZDDP in the R oil? Things have changed drastically in the last few years. You have to be careful what you read on BBS car sites as it can be 2 year old information. even the diesel oils as of Jan. 2007, have removed ZDDP to meet polution control regulations.
Rick Crawford

OK J, I'll take the bait. How do you know?

J Salbego - we are waiting for your info.

I just refilled my gearbox/OD with EP 90 after clutch replacement and am now thinking that I should drain it out and refill with the Valvoline 20/50R before I do a test run.


75 TR6
B.J. Quartermaine


I have owned many Volvo with the same OD and it was Ford type ATF recommended in owner manual for such set-up.

J. G. Catford
This is the cost incured, along with shipping, to do the rebuild. Herman Van Den Akker did the rebuild, and stated that the 80 or 90wt. gearoil is too thick for the overdrive to operate properly. He also recommened 20W50 Valvoline Racing oil, which Don Elliott has used successfully for 94,000 miles. Then I read Quantumechanics recommends SAE 30 straight Non-Detergent, which I have in the gearbox at present. Keep in mind I have not driven the car on the highway, but I will not be using 90w gear oil. So which way to go 20W50R or 30 non-deter.???? Don makes a good case, with real life miles.
Joe S.

So Ken, Herman and I all agree. I've known both for close to 20 years and for Ontario TR owners, Herman lived about 10 years in Toronto before moving to sunnier climes.
Don Elliott

Baed on the above, I drained out the fresh EP90 and refilled the gearbox with the recommended Valvoline 20/50R prior to running after the clutch change. I must say the OD does operate very smoothly now!

Thanks as always for the advice received on this BBS.

75 TR6
BJ Quartermaine

This may explain why so many TR6 owners on previous threads talked about having to use their clutch when shifting into overdrive. I have never used 80 or 90 weight oil and I have never needed to use my clutch when shifting into or out of overdrive. It always shifted so smoothly.
Don Elliott

This thread was discussed between 25/04/2007 and 01/05/2007

Triumph TR6 index