gear trans: going from syn blend to full syn

[big bubba]

fellow members:
have 2 Toyota manual gear transmission (older) vehicles that i have been using Mystic 75/90 syn blend gear oil in for many years w/no issues at all. not sure of ratio of syn to dino base on that (GL5)...this is what the dealer uses & i purchase from them & change myself...but somewhat a pain to go & get & hand crank it out from them so considering going to full syn same viscosity & purchase locally. anyone see any potential issues w/that switch? no leaks or mechanical issues w/either trans. thx in advance bb

 

[Copperhead]

No issues. Go ahead and enjoy. It will work fine.

 

[Diamondpilot]

Nope!

Chris

 

[Egon]

What? You don't want to be pushing the clutch in just to turn the engine over or wait before the shifter works.

 

[RalphVa]

I'd go fully synthetic and never change it. Don't see why you'd ever need to change manual transmission or differential oil if it's full synthetic.

Ralph

 

[big bubba]

What? You don't want to be pushing the clutch in just to turn the engine over or wait before the shifter works.

hey man, been there so many times don't want to count...but did notice even from the start way back when i purchased my truck in early 90's, in this kind of weather, the syn blend based fluid is so much easier on the shifter linkage alone @ cold starts. all original drive train on my '92 yota truck. thx

"I'd go fully synthetic and never change it." thx ralph for vote of confid.... although i just use conventional GL5 in my tractor ft axle, syn is the way to go in geared transmissions for vehicles.... just didn't know about going to the full syn route from blends as you hear about seal compromise, etc. thx again bb

 

[Jkott]

I'd go fully synthetic and never change it. Don't see why you'd ever need to change manual transmission or differential oil if it's full synthetic.

Ralph

Sheer/pressure breakdown (oil squished between the gears under pressure), Heat and Age oxidation/breakdown, wear metal particles, and contamination from water leaks or condensation. There are a *LOT* of reasons to change fluids regularly whether they are synthetic or not. Probably more important with the unfiltered ones like axle gear lubes and manual transmissions.

The synthetic gear lubes are less prone to sheer breakdown and are usually more resistant to heat breakdown, but they are just as susceptible to wear metals and contamination as conventional.

To each his own, but your statement is why I tend to buy new equipment rather than buy used and hope the previous owners did proper maintenance.