its for a 86 nwc t-5 and i want to use gear oil, but what weight? 80w-90?

 

Why gear oil?

 

 

why not gear oil? and i would prefer it bc its thicker and last longer.

 

If you're going to use gear oil, make sure it's yellow metal safe. GL4 gear oils should be safe. I'd avoid combo GL4/GL5 oils unless the label specifically reads it's safe for yellow metal.

Some synthetic GL5 oils are safe for yellow metal. Again, read the label.

As far as what grade to use? Depends on what available. I would just stick with whatever lube is commonly recommended. Why deviate?

 

GL4? GL5? yellow metal? and its not so much as im deviating bc the trans is beening rebuilt, hell when i got the thing it had motor oil in it, had a tag saying 5w-30 bolted to the case. and im gona be getting the gear oil from a parts store, dont want it to be to heavy tho.

 

Lots of manual transmissions call for motor oil. ATF is recommended for the W/C T5. There's not a lot to be gained by putting gear oil in it.

 

Yellow metal = the material the syncros and bushings inside the transmission are made out of. Bronze, brass, copper and other alloys.

GL4/GL5 are service grades established by the American Petroleum Institute (API). Some gear oils contain sulfur-based anti-wear additives (that's what makes rear end gear oils stink). Sulfur based anti-wear additives are corrosive to yellow metals.

If it calls for 5w-30 engine oil, just put that in. A nice upgrade from regular 5w-30 engine oil is Redline MTL. It's synthetic and is of the correct grade.

http://www.redlineoil.com/content/fi...ech%20Info.pdf

 

aaa ok. its gettign a fresh rebuild and its a nwc t-5. so since no1 has given me a weigh for the gear oil i guess i could put 5w-30 motor oil back in.

 

Yep. I'll tell you what you can expect if you put 80-90 in a unit intended for 5w-30 or ATF. It will shift like a 10 ton truck on a bad day. I made this mistake one time and noticed the problem right away. I went ahead and gave it to the customer to let them try it. I had the car right back because the owner could hardly shift gears the next morning when the oil was cold.

I know that 5w-30 seems awfully light for gears but anything heavier and you'll have a hard time shifting. Bad if you like grabbing gears. One suggestion if you want something with higher sheer strength, is Redline motorcycle engine oil. Motorcycle engines use the same oil for the crankcase and the transmission. Redline is formulated for maximum sheer strength(prevents metal to metal contact) while maintaining low viscosity for minimal drag(less parasitic power loss). Or just use a high quality synthetic motor oil.

 

ok ok ok so even tho everything is beening replaced with this rebuild (excluding gears and forks) i still should put 5w-30 in. very well 5w-30 it is, and i wanted gear oil bc its thicker, would leak out as easy and would stick to gear more.

 

"Thickness" doesn't have much to do with "leakiness" or "stickiness".

 

The stickiness you talk about is called pour point suppression, it is a measurement of how well an oil clings to a surface. It's more a matter of what additives an oil has. Sheer strength is just as important as it is a measurement of how much pressure it takes to displace the oil between two surfaces. Synthetics generally perform better on both fronts. I would hope that you're not worried about leaks on a fresh rebuild.

 

75W-90 Mobil1 is the cheapest best most widely available choice.

 

All the T-5s I have taken apart or rebuilt, have used ATF or GM syncromesh. Ford and GMs.
I don't think I have ever seen 1 with gear oil in it. I know there was but everyone made the change to atf for milage and better driveability.

If you haven't seen it here is a bunch of info about T-5s

http://www.jalopyjournal.com/forum/s...d.php?t=171291

 

ok thanks every one, i have my answers and now must think.

 

Here is what I used in mine.

https://www.oreillyauto.com/detail/b...+80W-90+&pos=0