5 Speed Oil Question

[Yaboyolin]

Hey guys, I finally got my 1978 Datsun Running. If youve been following my problem in the fuel injection section, you should know that this car has already been a headache. Anyways. This car was a 5 speed swap. Not sure if out of a ZX or just a Z. Ive got a 5 gallon bucket of 80-90w gear oil sitting in front of me, will this work? Ive read about GL4 and other weights, but this stuff is free and works good (My stepdad owns 15 tractors and this is all he ever uses). Ive read that you can use 80-90w, but I didnt know if there was a difference between the ZX and Z trannys as I dont know which this is. Thanks

 

[Jeff G 78]

I strongly suggest Redline MT-90.  Don't just throw any old oil in there.

[Zed Head]

2 minutes ago, Yaboyolin said:

Hey guys, I finally got my 1978 Datsun Running. If

Ive got a 5 gallon bucket of 80-90w gear oil sitting in front of me, will this work? Ive read about GL4 and other weights, but this stuff is free and works good (

 

How?  You have to tell what was wrong if a bunch of people have made suggestions.

If you've read about GL-4 and-5 then you know that the wrong fluid can destroy your synchro gears.  So the equation is - do you feel lucky?  Is there a brand name and description for the oil or is it mystery fluid?

 

[Yaboyolin]

Nothing's wrong. I just got the car running and am doing a complete fluid flush because I don't know how old any of it is. The oil I have is GL5 80-90w. Its shell gear oil. We run it in other transmission on various vehicles and tractors on the farm, never had an issue. I'm just curious if 80-90w will work on all 5 speed  Z and ZX series transmissions

[Dave WM]

GL-4 in the transmission.

[SteveJ]

From the factory service manual:

 

[Yaboyolin]

Alright, thank you. I was just worried about the fact that I didnt know if this granny came out of a Z or ZX and I dont have a manual on a ZX

[Jeff G 78]

Same gear oil for both.

[Yaboyolin]

Where exactly am I supposed to buy GL4 oil? Ive called all the local places and they only carry GL5 or they carry GL4 140w

[Jeff G 78]

https://www.amazon.com/Red-Line-50304-Transmission-Transaxle/dp/B000CPCBEQ

[Zed Head]

Somewhere in the past somebody's trans got damaged by a GL-5 spec oil and ever since there's been the "all GL-5 spec oils destroy yellow metals" boogie man.  There are GL-5 spec oils that work fine in yellow metal transmissions.  But the safe bet is a fluid that specifically calls out manual transmissions, and/or yellow metals.

There must be more on that mystery can of oil that the word "Shell".  Big picture wise though, the transmission is sensitive to the fluid used.  For a a few extra dollars you can avoid a lot of trouble.

[zacny77]

Owned my 280Z for 40 years. Have had really good luck with Redline MT90. Two quarts should do it.

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