Gear Oil (changing from synthetic to regular)

[Rollamaster]

I have had synthetic gear oil on my corolla 1997 which now has 138k kms. I am just feeling like its time for me to change the gear oil again as it has been quite some time since when i had the last change.

WOuld it harm in anyway if i use the regular gear oil (not synthetic) this time as it was synthetic last time, i have felt more comfortable using regular instead of Synthetic and am concerned now if i can go ahead and use regular instead,

All advise is much apprecaited. i would also very much apprecaite if any of the expreinced users would suggest the best oil to use (should i use the gear oil available at Toyota dealership ? or are the third party ones better ?)

Thanks again !

[BDSL]

You can switch back and forth.

[PhatRoyale]

Switch to your hearts content!

[sequoiasoon]

Switch anytime BUT remember that synthetic flows easier when cold and normally doesn't breakdown as easy.

That said I switched mine many times with syn (Pennzoil) and dino (Toyota, Pennzoil, Mobil) and for a while I had a problem with grinding of the gears at higher rpm's both up and down shifts. Dealer and independent mechanic said tranny rebuild needed (they tried changing fluids first and clutch etc).

My Friend who works for BMW said to try BG Synchro Shift II as thats what BMW was using to clear up some of the same type problems. $60 later grinding was gone for good. I changed it every 2 years after that just because and stuck with BG since it eliminated needing a rebuild.

Many other people I know recommend Redline, MT90, and amsoil also.

As for the cold flow thing. My old Honda in college had dino in it and one winter I had REAL troubles shifting until it ran for a while and warmed up (-20F outside). The following year I had Mobil1 in it and it shifted fine even at -25F outside. You be the judge. What's the current temp in Toronto?

[Rollamaster]

Originally Posted by sequoiasoon

Switch anytime BUT remember that synthetic flows easier when cold and normally doesn't breakdown as easy.. What's the current temp in Toronto?

Sorry I am not a pro at Transmission fluids, but just to understand clearly - are you suggesting that synthetic is better in a car as old as a 97 corolla for manual transmission. I was thinking may be Toyota Tranny oil would be better but really am still open to options.

Its usually around -10 C now however can go upto -30 C at times, so in other words it very cold most of the year round however we tend to get the worst of summer season as well.

I am getting some occasional grinding feeling while shifting and thats causing discomfort within myself as the i know the clutch is just fine and the transmission itself is carefully used. I was trying to get may some oil in it that would help me reduce or eliminate griding feeling altoghether

[PhatRoyale]

Just stick with the Redline MT-90..... synthetic will always suit a wider variety of driving conditions than conventional tranny fluid. One of them being better at flowing well in extremely low temperatures. There's a reason why it's more expensive.

[Rollamaster]

Originally Posted by PhatRoyale

Just stick with the Redline MT-90.

Will do.

and thank You everyone for their feedback ! Happy Holidays !!

[sequoiasoon]

I would switch to the BG Synchro Shift II and run it for at least 100 miles before forming opinions. You say you are experiencing some grinding and are currently using MT-90 correct?

Over my time I had used Toyota dino, Mobil Dino and Syn, Pennzoil Dino and Syn. The switch to BG was based on my friend at BMW who said it was eliminating the same type light grind issues on many the cars that came to the shop.

Toyota, my normal independent mechanic and a tranny shop said I would need a rebuild to get rid of my grinding. All of them had tried changing the fluid first (see above) and had me drive at least a week. No change from any of them so the BG was my last effort. I changed it hoping for miracles expecting no change. Leaving the shop I noticed no change and was bummed out. 30 miles later on a 70 mph 5-4 downshift that was ALWAYS a light grind, to my surprise was smooth. Took off from the light and at 5500 the 1-2 shift that would do it at high RPM was also gone and never returned for the next 100k+.

Talking to BG tech dept and my normal mechanic and friend, common consensus is that whichever other fluids based on viscosity, were causing the synchros to slow to fast because of drag in the close tolerances even though they were all either GL-4 or GL-5 recommended weight.

http://www.bgprod.com/products/driveline.html and you can also hit the findashop for local dealer. Otherwise order up on the net.

Reviews.
http://www.prostreetonline.com/x/bg-synchroshift.asp
http://www.m5board.com/vbulletin/e39...shift-2-a.html