GM F40 Transmission, synchromesh?

[Dillonkennedy003]

Hi All,

I’m seeking some help selecting manual transmission fluid for the F40 6MT in my Saab 9-3 Aero.

Saab recommends the GM 0063 GL-4 MTF but I have heard from others that this fluid does not improve shifting feel/performance. I have read from other forums that Redline MTL 75w-80 does in fact improve shifting but I was wondering if there was a third option: friction modified AC Delco synchromesh.

I used this stuff in all my Hondas with great success - I was wondering if this fluid could be successful in the F40 as well.

Does anyone know more about the properties of the synchromesh, would it meet the GL-4 rating? Information was difficult to come by via googling.

I don’t necessarily mind being a Guinea pig to test it out, but at the same time I would rather not damage my transmission.

Let me know what you all think.

Thank you

 

[ceecbtg]

Official oil is 75w85 true GL4, ZDDP based, false syn good quality. It's spec you should search.

Redline 75w80 is very good oil, stronger additive. It's little thinner but will work same or better than official oil.

Other true GL4 ZDDP 75w85 options:
Redline MT-85
Amsoil Syncromesh (5w30)
Castrol Syntrans
Tutela Geartech
Tutela Matryx
Hyundai MTF

There are any GL4 compatible (different additive), it should work well like Penrite Pro Gear 75w85 and Motul Motylgear 75w85

Discard because same oil: Castrol BOT 402, Castrol GM 93165290.

 

[tcp71]

Did a bit of experimenting with the 6mt in the mazda. Used Mazda OEM (it came used with 60k miles on it), Ford XT-M5-QS, Valvoline Synchromesh Manual Transmission Fluid and Amsoil Syncromesh (5w30). The best result was actually the Amsoil fluid which I originally bought from amazon.

 

[ctechbob]

Did a bit of experimenting with the 6mt in the mazda. Used Mazda OEM (it came used with 60k miles on it), Ford XT-M5-QS, Valvoline Synchromesh Manual Transmission Fluid and Amsoil Syncromesh (5w30). The best result was actually the Amsoil fluid which I originally bought from amazon.

I was going to mention the Ford stuff. I know back in the day that was the go-to in Miatas with balky transmissions. I got rid of the car before I had a chance to try it, but lots of people swore by it.

 

[dfarr67]

In the Honda- gone thru Honda MT2, Synchromesh, finally on Pentosin MT2 which they have discontinued. My problem was cold weather notchiness.