MR2 Roadster Owners Club

The Workshop => General => Topic started by: MR2Adam on February 24, 2018, 23:47

Title: Gearbox Oil-Which ones best??
Post by: MR2Adam on February 24, 2018, 23:47
Having a service soon on my Roadster so I'm going to get the gearbox oil changed. But which oil is the correct one and which one is best?

Also, as my car is a 6 speed and has the LSD (I presume), does the oil need to have the additive for the diff?
Title: Re: Gearbox Oil-Which ones best??
Post by: 1979scotte on February 25, 2018, 07:30
I think most people go for mt90
Title: Re: Gearbox Oil-Which ones best??
Post by: Bossworld on February 25, 2018, 08:18
Happy to be proved wrong but I think I read ours don't need LSD specific gearbox oil. If someone could confirm if we have a Torsen or Viscous Coupling that'd be handy.

Did a lot of research last year and apparently back in the day, GL-5 gearbox oils could trash brass synchros.

MT90 is rated GL-4 and very highly regarded in this community.

But you'll find a lot of modern gearbox oils are rated for both GL-4 and GL-5 - the brass synchros thing seems to be a legacy issue.

I'm running this

https://www.nielsencdg.co.uk/total-transmission-dual-9-fe-75w90-manual-gear-box-oil-tot-201656/

Title: Re: Gearbox Oil-Which ones best??
Post by: shnazzle on February 25, 2018, 08:54
I've always stuck to MT90. Yes it's 35 quid but how often do you replace it? And the difference is quite noticeable if you've never replaced it so it justifies it in your head :)

As far as fluids go, I just go for the best. Saving 20 quid on something I replace maybe once or twice a year in case of engine oil, why scrimp?
Title: Re: Gearbox Oil-Which ones best??
Post by: MR2Adam on February 25, 2018, 09:07
Quote from: shnazzle on February 25, 2018, 08:54
I've always stuck to MT90. Yes it's 35 quid but how often do you replace it? And the difference is quite noticeable if you've never replaced it so it justifies it in your head :)

As far as fluids go, I just go for the best. Saving 20 quid on something I replace maybe once or twice a year in case of engine oil, why scrimp?

Ah that's good to hear it will make the difference! I've heard Redline oil is that stuff to go for.

How much oil does the Roadsters gearbox take?
Title: Re: Gearbox Oil-Which ones best??
Post by: Carolyn on February 25, 2018, 09:34
Quote from: Bossworld on February 25, 2018, 08:18
Happy to be proved wrong but I think I read ours don't need LSD specific gearbox oil. If someone could confirm if we have a Torsen or Viscous Coupling that'd be handy.

Did a lot of research last year and apparently back in the day, GL-5 gearbox oils could trash brass synchros.

MT90 is rated GL-4 and very highly regarded in this community.

But you'll find a lot of modern gearbox oils are rated for both GL-4 and GL-5 - the brass synchros thing seems to be a legacy issue.

I'm running this

https://www.nielsencdg.co.uk/total-transmission-dual-9-fe-75w90-manual-gear-box-oil-tot-201656/

Our diffs are Torsen.
Title: Re: Gearbox Oil-Which ones best??
Post by: Ardent on February 25, 2018, 23:26
I went for mpm gear oil of the correct spec and veryhappy with that.
Mt 90 "might" be better. I dont know.
I have yet to see a review where 60 70 80 thousand mile used gear oil is dropped, replaced with something non mt90 ran for a few thousand miles then dropped again for mt90 and compared.
Is it because it is mt90 or is it because it is new oil that people say how much better it is.
Strangely enough, my "fresh" stock suspension felt so much better than my old original shocks.
Title: Re: Gearbox Oil-Which ones best??
Post by: Topdownman on February 26, 2018, 09:55
Quote from: MR2Adam on February 25, 2018, 09:07
Quote from: shnazzle on February 25, 2018, 08:54
I've always stuck to MT90. Yes it's 35 quid but how often do you replace it? And the difference is quite noticeable if you've never replaced it so it justifies it in your head :)

As far as fluids go, I just go for the best. Saving 20 quid on something I replace maybe once or twice a year in case of engine oil, why scrimp?

Ah that's good to hear it will make the difference! I've heard Redline oil is that stuff to go for.

How much oil does the Roadsters gearbox take?

All from memory, is it 1.7 litres? I am pretty sure I bought 2 bottles of the mt90. I think the mt90 is popular because it can make the gear change a bit slicker.
Title: Re: Gearbox Oil-Which ones best??
Post by: 1979scotte on February 26, 2018, 10:08
@Ardent (https://www.mr2roc.org/forum/index.php?action=profile;u=20018)

Although I have put MT90 into my 2 and would do again I agree with Jason's sentiment.
After thousands of miles changing it for anything of the correct spec will make a positive difference.
Title: Re: Gearbox Oil-Which ones best??
Post by: Joesson on February 26, 2018, 10:31
Slightly off gearbox topic, but to do with lubrication and in the same general area, I mentioned a while ago about a slight leak from the drive shaft boot and consequently " "drained" what was once grease from the inner and outer bearings/ boots and replace with grease.
No noticeable difference but I felt better after seeing what came out and what I put back in.
Psychology, rather than physics perhaps plays a part in our perceptions of change.
Title: Re: Gearbox Oil-Which ones best??
Post by: ChrisGB on February 27, 2018, 08:01
I've swapped one fresh gear oil for another in a stock MR2 box. 28,000 miles on stock gear oil, I was not too happy with shift quality, so filled with Silktran 75W90. This was a bit too slippery, changes where very notchy and obstructive. Drained and filled with Redline MT90 which proved to have the best shift quality of the 3. When I went turbo, it was suggested that although MT90 gives good shift quality, it may not be the best for high stress applications, so went to a Shell product, not sure which one. Good shift quality, but not quite as slick as MT90.
Title: Re: Gearbox Oil-Which ones best??
Post by: Ardent on February 27, 2018, 23:19
MR2Adam

Given that Chris is arguably running the most power on here, if MT90 works for him, it will work for you.

I am running half or less juice than Chris. MPM is more than smooth enough for me.
Title: Re: Gearbox Oil-Which ones best??
Post by: tow on March 7, 2024, 12:55
I am using Castrol Syntrans Multivehicle 75W/90. MT90 isn't available in my area, and the Castrol has always done good on my transmissions. Had one that had hard gearing, that got a lot better after changing to Syntrans.
Title: Re: Gearbox Oil-Which ones best??
Post by: puma2 on March 7, 2024, 13:00
 :) i have used mt90 twice now just  my go to from other people advice on here and from the who  does the work :)  :)
Title: Re: Gearbox Oil-Which ones best??
Post by: Carolyn on March 7, 2024, 14:47
Quote from: tow on March  7, 2024, 12:55I am using Castrol Syntrans Multivehicle 75W/90. MT90 isn't available in my area, and the Castrol has always done good on my transmissions. Had one that had hard gearing, that got a lot better after changing to Syntrans.
I buy it from Fleabay
Title: Re: Gearbox Oil-Which ones best??
Post by: J88TEO on March 7, 2024, 16:16
Quote from: Carolyn on March  7, 2024, 14:47I buy it from Fleabay
Same here.
Title: Re: Gearbox Oil-Which ones best??
Post by: MarkB1 on April 1, 2024, 14:11
Millers TRX 75w-90.....it was actually the semi synthetic version but seems to work well, gear change is great. I'm not doing big miles or hard driving.