Has any one tried a synethic in the tranny of the manuals? whats the verdic does it help, and are there any drawbacks. What about synthetic blends?
thanks
james

Seems a pretty technical question. All it does is lube the gears by flicking the oil around. Pretty low tech. They recommend diesel engine oil here for the tranny. Its a pretty harsh/hot environment here, and it obviously does the trick. Obviously there is a balance here between economy and performance, as most people are poor. The diff seems to be a different story, however. Mega thick oil for this. The locals use SAE 90 for the diff, but Isuzu recommend SAE 140 (this costs much more and is thicker); I prefer to use the thicker oil as it gives better protection.

</font><blockquote><font size="1" face="Verdana, Tahoma, Arial, Helv, Helvetica, Sans">quote:</font><hr /><font size="2" face="Verdana, Tahoma, Arial, Helv, Helvetica, Sans">Originally posted by amunro:
<strong>They recommend diesel engine oil here for the tranny.</strong></font><hr /></blockquote><font size="2" face="Verdana, Tahoma, Arial, Helv, Helvetica, Sans">Not in the MUA5. Isuzu recommends 5w-30 for most enviroments. If i remember correctly, diesel engine oil is much thicker (10w-40, 20w-50).

James, I ran a full synthetic in my MUA for a while. I switched to it hoping it would help calm the driveline noise i now get at 65mph, but in reality, i didn't notice any difference except in the check book. I'd say just go with normal dyno oil here.

-Rob

TiT (This Is Thailand). Well the hotter your environment the thicker the oil you need <img border="0" title="" alt="[Razz]" src="images/icons/tongue.gif" /> Actually, it was 20w 50 that went into my MSG transmission (which is a 1988 pickup). I would be much more selective about what I put in my newer one, though, which has the MUA <img border="0" title="" alt="[Razz]" src="images/icons/tongue.gif" /> . The proper oil went into the diff, which is much more demanding on the oil.

My 1998 Amigo has a Borg Warner T-5 manual Transmission. It takes ATF Dexron III or Mercon, however, When I last changed it I put in #7500 Power fluid from Lubrication Engineers. I can't believe the difference!! Before it would hang up a little, now it's soo smooth, like silk. Temperature dropped also.

Jon V

P.S. It's 100% Parrafin oil. Synthetics don't carry as heavy a load in gearboxes as the parrafin oils.

Jon V

I've personally tested many types of oil while in the military. Synthetics are far superior in every way. I've ran Amsoil 5w-30 in my 86 trooper tranny for 336,000 without a single problem. Own a large bass boat and towed many trailers all over Arizona,(just about the hottest spot in the nation), and California. I did tear down my engine at 206,000 due to catalytic converter clogging and cracked the head, but the bottom half was not just within factory specs, but on the minimum side! The inside of the engine was totally clean. It's one thing to always read about and do tests on the stuff, it's another to actually tear down your own engine to find it almost brand new 8 years later. I could personally run lab test of synthetic, specifically Amsoil and some Castrol syntecs, that had 25,000 miles or so and it would still outdo brand new conventional oil in just about every catagory, (falex wear tests, boil off tests, etc). Synthetic gear oils (normally Valvoline was tested) give approx. double the protection while the Amsoil I tested one time gave approx. 3-4 times the gear protection while still maintaining a positive flow at -30degrees plus! While conventional engine oils have improved in high heat environments, conventional gear oils cannot hold a candle to synthetics.
Not puttin down conventional lubricants. They will protect your vehicle just fine, especially today's more advanced conventional lubricants. But for the long term performance minded person who demands only the best protection and longest life of their internal parts, synthetic lubricants must be used. If you cannot find Amsoil, Castrol makes a very good synthetic and Valvoline would be 3rd.

The power fluid in the 98 Amigo above was an excellent choice. You can obviously see and feel the difference the choice of fluid makes. Remember too in automatic tranny's, when the lubricant temperature is lowered just 10 degrees, and I mean only 10 degrees, the fluid life is doubled! Even GM tranny lubricant spec. sheets will tell you that. I believe all automatic trannys should have a cooler on them. Combine a cooler with syntentic auto tranny fluid and you have much longer tranny life.

I would also like to say something about the thicker oils. Be very careful!!! Notice the 98 Amigo with the manual tranny that takes Dextron III. There is a reason for that. The reason is that when computers now design and manufacture our parts tolerences are much tighter and more precision between the gears, synchros, countershaft bearings, etc, that normal thicker oil will have a difficult time getting BETWEEN all those parts, shaft surfaces and needle roller bearings and lubricating them properly. New engines take 5w-30 or 0w-30 because the bearing tolerences are so much tighter as compared to yesteryear, any thicker oil will not allow proper lubrication. Thinner oils do possess the additives to lubricate just as well and even better than thicker oils due to the fact that they get "in and out" of an area quicker, thus dispersing heat and reducing friction more efficiantly. Since gearboxes and differentials "splash" their oil around, thinner gear oil,(75W-90), with a good hypoid additive will always produce superior lubricating abilities over say 90W-140, which doesn't splash half as good. Yes, there are specific applications which will use 140, but we're talking isuzu trucks and the like.
Remember also, my 86 trooper takes 140 gear oil if temps are over 90 degrees constantly and 80W-90 for all other applications. But that was 16 years ago. 75W-90 gear oil of today is far superior in its additive package and lubricating abilities than any of yesteryears 140 gear oil ever was. So I use 75W-90.
Today's synthetic gear oils, if they could speak, would laugh at our trucks and the ease of which they could protect them!