Add ZDDP to gearbox oil?

[Rob Glasgow]

And at the Standard station where I bought my gas, the attendants kept those oil bottles cleaned and spotless.

 

[Keoke]

Just use a high quality racing oil in engine & Tranny N U be OK

I did it this way with no problems at all so I only had to carry one type of oil in the boot while traveling all over USA.

 

[glemon]

It has been a couple years, but I didn't have too much trouble finding non-detergent 30 weight--it is usually only sold in the cheapest store or discount brand. I used to run multi viscosity, never had issues, but have read it can cavitate or foam in a gearbox.

 

[Rob Glasgow]

I get my ND 30 wt at the local NAPA store. It's their brand.

 

[bdcvg]

Tractor supply has it too.

 

[tahoe healey]

I may have missed this in the past but, what is the difference between ZDDP and ZDDP "plus"? Plus is probably an advertising gimmick because we have been trained to think plus is always better. (well, we don't always like plus size strippers and pole dancers)

 

[AUSMHLY]

How about adds that say, New and improved. If it's a new product (not a new version) then how can it be improved at the same time.

 

[John Turney]

SAE engine oil viscosity grade 50 must have a viscosity between 16.3 cSt (centiStoke) and 21.9 cSt at 100C (212F) - This is the manufacturer's requirement.

SAE gear oil viscosity grade 90 must have a viscosity between 13.5 cSt and 18.5 cSt at 100C. That's one reason why MT-90 works well in a Healey transmission. Gear oil viscosity grades are different than engine oil viscosity grades.

SAE engine oil viscosity grade 30 must have a viscosity between 9.3 cSt and 12.5 cSt at 100C. That's too thin. Detergent vs non-detergent is immaterial.

 

[AUSMHLY]

I've used 20w-50, MTL-90 and recently switched to 30w non detergent as Healey Surgeons recommends it.
I have noticed that the shifting is a little smoother then 20w-50 and doesn't leak as much as MTL-90. Still leaks but I think that's what Healey's do. I bought the 30w at the local Napa store.

 

[Michael Oritt]

I may have missed this in the past but, what is the difference between ZDDP and ZDDP "plus"? Plus is probably an advertising gimmick because we have been trained to think plus is always better. (well, we don't always like plus size strippers and pole dancers)

ZDDP Plus is simply a brand of ZDDP additive. Since its strong suit is to protect flat tappets I don't see why it would be useful in transmissions,