Transmission and gear oil

[Joeype70]

I know this is very hot topic all over the forum as i have been reading many posts. Many people mention to use the 80w90 gear oil. My question is, if i grab a gallon of 80w90 gear oil, is this good to use in my gear and transmission? I see many people talk about the NAPA fluid and others even mention 20w50 motor oil in the tranny. Not going to personally you any motor oil in my tranny. Has anyone used Super Tech 80w90 high performance gear oil from walmart? I want to change both and just want to ensure i use the proper fluids. Nothing that will beat up the yellow metals. Thank you!!

[RRoller123]

Must be GL1, NON EP, or it attacks the synchros. NAPA has GL1 by the gallon at a reasonable price. Csaba used to say that he used 20W-50 motor oil with good results, and he is one to know!

[Joeype70]

Thanks for the reply. So can i use the NAPA for both the gear and trans?

[RRoller123]

Not sure I follow you? NAPA GL1 in the gearbox, Castrol or other 80W-90 in the Differential is the way to go.

[PhillySpider]

can someone post a "how to" as far as where the access is to add fluid and drain fluid? I've not done this in my 1980 yet w/56K original miles on it. Knowing oil degrades over time is it recommended to just change it?

[Joeype70]

Yes, sorry. I ment can I use both 80w90 from NAPA in my trans and differential/axel oil?

[Odoyle]

Factory manual says:

Transmission:
Manual 1.75 qts/ SAE 80W/90 oil (not EP) containing special anti-wear additives.
Auto 3.0 gts DEXRON auto trans fluid.

Rear axle:
1.40 gts. 80W/90 EP (extreme pressure) oil

Finding the right gear oil can be difficult due to the soft yellow metals in the trans. I switched from using NAPA mineral gear oil to the manual trans fluid from amsoil and shifting has never been smother.

http://www.amsoil.com/shop/by-product/t ... 2fmtf.aspx
http://www.pennzoil.com/en_us/products/ ... U9ZW5fdXM=

[DieselSpider]

You have to use a different lubes. The transmission can not use any lube with a sulfur or other potentially corrosive pressure additive however the diff absolutely needs the pressure additives. Brand is not important but having it free of corrosive pressure additives is critical for the transmission.

[MattVAS]

Yeah its regular old Gear Lube GL1 for the Transmission (non AP or EP)
Then GL5 for the rear end

Many Napas do offer GL1, although I've had a lot of customer recently say their Napa have stopped bringing it in.

We do offer GL1 in quart bottles if your local shops don't have it.

You can also try tractor supply stores.

[PhillySpider]

Process????

[Joeype70]

Matt,

Thank you for the information. Much appreciated.

[phaetn]

Process????

For manual transmission: Drain bolt at bottom of gearbox casting. DO NOT open until you know you can open the fill hole first so you don't get stuck having emptied used oil with no way to refill. The fill hole is quite hard to get at on the passenger side of the casting and requires a 17mm wrench and is right beside the exhaust pipe. There's a protrusion in the gearbox casing that can make it hard to get good clearance with a wrench. Best to use a ratcheting wrench for ease.

I've done it while sliding under the car and filling with a pump. PITA as my car is so low I have to put it up on jacks first and there's still not a lot of room. I've also going to a local garage and had them put it on a lift and squirted oil in with a long tube on the bottle cap. Worked okay, but had to pay for lift time. Yesterday I went went to a drive in oil-changers with a pit that is right by my work. I've been there a few times with other cars and once with the Fiat; they know me and so let me go down the stairs to get under the car when it wasn't busy and adjust whatever I wanted. Easy-peasy. (Bought the manager a six-pack of beer when I was done).

As others have said, either use 20W-50 motor oil, or I use Quaker State Synchromesh (or a Valvoline equivalent) that is safe for yellow metals because of the brass synchros. Fill until it starts to drip out the fill hole.

Diff: same deal. Drain bolt and fill bolt. 17mm. Accessible from rear of car and you don't even have to jack it as it is quite exposed. Use 80W-90EP (Extreme Pressure) oil for this.

Hope this helps.

Cheers,
phaetn

[PhillySpider]

Process????

For manual transmission: Drain bolt at bottom of gearbox casting. DO NOT open until you know you can open the fill hole first so you don't get stuck having emptied used oil with no way to refill. The fill hole is quite hard to get at on the passenger side of the casting and requires a 17mm wrench and is right beside the exhaust pipe. There's a protrusion in the gearbox casing that can make it hard to get good clearance with a wrench. Best to use a ratcheting wrench for ease.

I've done it while sliding under the car and filling with a pump. PITA as my car is so low I have to put it up on jacks first and there's still not a lot of room. I've also going to a local garage and had them put it on a lift and squirted oil in with a long tube on the bottle cap. Worked okay, but had to pay for lift time. Yesterday I went went to a drive in oil-changers with a pit that is right by my work. I've been there a few times with other cars and once with the Fiat; they know me and so let me go down the stairs to get under the car when it wasn't busy and adjust whatever I wanted. Easy-peasy. (Bought the manager a six-pack of beer when I was done).

As others have said, either use 20W-50 motor oil, or I use Quaker State Synchromesh (or a Valvoline equivalent) that is safe for yellow metals because of the brass synchros. Fill until it starts to drip out the fill hole.

Diff: same deal. Drain bolt and fill bolt. 17mm. Accessible from rear of car and you don't even have to jack it as it is quite exposed. Use 80W-90EP (Extreme Pressure) oil for this.

Hope this helps.

Cheers,
phaetn

Huge help, THANKS!

[Joeype70]

Thanks for the information Phaetn

[geospider]

Seems that ordering from VAS is the only option I can find. Not a lot of tractor shops in the SF Bay area.
local auto parts stores don't carry it and will tell you that the GL5 is just fine. Great to have this forum to know what is right for these cars. At least I can get the Rotella at Autozone. The size of the oil filter surprises the young guys at the parts store.
Like to buy local when I can and the shipping is as much as the oil.