Oils/Lubes front to back....what to use and how much? Syn, conv? Royal P, Mobil?

[thefarmboy21]

I see oil types and fluid capacity threads come up from time to time and it's time for me to go through all of mine, so I thought I'd compile it all into one. I think this would make a good "sticky" but that's not up to me.

Anyway I'm getting ready to change all the oils in my K20 from front to back and I'm wondering what the capacities are and what I should use. My truck is an 86 K20, 4-speed, NP208, 4.10 limited slip and the fresh 350 is ready to go in as we speak. I know the 350 holds 5qts of whatever I want to dump in, but what about everything else? Transmission, T-case, front and rear axles, even wheel bearing and U-joint grease? I'm thinking I want to put Royal Purple all the way through the truck, but I'm not sure if synthetics are good or "recommended" anywhere besides the motor? I think most of us belong to this site because we love these trucks and want them to last forever. Mine was given to me by my grandpa and has less than 82,000mi on it. On average I drive it 1000 miles a year, so I don't care to buy the high priced stuff, because hopefully I won't have to touch any of it for a long time.

So let's have it.....what are the capacities to everything 73-87 GM trucks and what do we use and not use and why?!?! Thanks....can't wait to see how this thread turns out.

[thefarmboy21]

Soooo.....no one on this forum uses oil? And no one knows transmission and rearend capacities?

[Stewart G Griffin]

Do you have the owner's manual?

i usually put in 5 qts. oil in my smallblock [(1 qt for filter change AND) even not putting the filter change into consideration, 1qt over is not going to hurt anything and you'll have 1qt extra in reserve]   i use Redline Synthetic 10W-30;  There is a notion that a stock engine with flat lifters with stock spring pressures DOES NOT need synthetic or additives, but if synthetic can last twice as long as conventional oil before changing then the money is exactly the same anyways.  So i feel safer this way while the controversy over synthetic vs. conventional oil continues.

[Captkaos]

There is a bunch of variables here..
TH350 holds 4 quarts, converter depends on size but in general, 3 quarts
TH400 holds 6 quarts, converter depends on size but in general, 3 quarts
700R4 holds 4 quarts, converter depends on size but in general, 3 quarts

10/12 bolt: 4.25 pints (2 qt 4 oz)

Oil is a consumable, so if you are changing it often I would spend a ton of money on it.  I put what ever is on sale in my 2 stock vehicles.  Mobile 1 synthetic goes in my Corvette (factory spec), my twin turbo truck gets Mobile 1 synthetic because I have it for the Vette.

 

[thefarmboy21]

Looks like the SM465 uses 4qts of 80w90 but some say 75w90 synthetic will improve shifting.

NP208 T-case uses Dextron III

[thefarmboy21]

Limited slip rears recommend a "friction modifier" does anyone know where to get it?
*Also, is it still recommended if you're using synthetic?

[Stewart G Griffin]

All the capacities are in the tech section:
http://forum.73-87chevytrucks.com/smforum/index.php?topic=18701.0

You'll have to do some digging, but it's all in there.

Here is a nice forum on oils if you really want to get into it:
http://www.bobistheoilguy.com/forums/ubbthreads.php

i think they were even saying NOT to use synthetic in the rear diff.