Spitfire Question on Transmission fluid for a 73 spitfires

[ScottFromNH]

Hi Guys,

I have a 73 spitfire with a 4 speed manual transmission (no overdrive) I am trying to figure out what transmission fluid I can use to replace what is in their? I was hoping I could get something at a local auto parts store ( and someone told me try the tractor store) Any help would be greatly appreciated

scott

 

[3798j]

Many here find Redline's MT90 works particularly well. I use (and like it) in both Triumphs, a Chevrolet "Muncie" and a Ford "Top Loader". It really helps the syncronizers do their job better. While it's not typically the easiest to find locally, Amazon can have it at your door in just a few days. https://www.amazon.com/Red-Line-50304-Man...8062&sr=1-1

 

[Don_R]

I've used Redline MT-90 in both of my Spit trannys 1 o/d and 1 non o/d.

 

[ScottFromNH]

Thanks Jay and Don. I just ordered some MT-90 so I can get my fluid swapped out in the tranny and the differential.

 

[TR3driver]

Just to be clear, MT-90 is for transmissions only. You don't want it in your diff.

 

[billspit]

Just to be clear, MT-90 is for transmissions only. You don't want it in your diff.

Why not?

 

[Andrew Mace]

MT-90 is not an "extreme pressure" (EP) lubricant, which the differential requires.

 

[ScottFromNH]

Hey TR3Driver and Andrew

Thanks for the heads up I didnt realize that. What do you recommend for the differntial?

 

[TR3driver]

MT-90 is not an "extreme pressure" (EP) lubricant, which the differential requires.

Well, actually it IS rated GL-4, which qualifies it as an EP lubricant. But it is also specially designed to enhance the friction required for good synchromesh operation, which is not something you want in a differential. Also Redline specifically recommends against using it in the diff.

My favorite for Triumph diffs is Valvoline full synthetic gear oil (SynPower). It works well and is relatively inexpensive and easily obtainable. My previous TR3A diff was already well-worn when I got the car, and I credit the SynPower for making it last another 200,000 miles (roughly) without any noticeable increase in backlash.

However if you wanted to stick with a RedLine product, their 75W90 gear oil should be a good choice too. Although rated GL-5, it contains none of the "active sulfur" additive that can be a concern with some GL-5 oils.