Transmission and gear oil

[hayesbd]

For the transmission, I switched to Redline MT90, which is a GL4 (no EP additives). All that is needed for the preservation of the synchros is GL4 or lower. I noticed quite an improvement in shifting and this should be readily available.

Brian

[RRoller123]

Redline MT 90 makes for easy shifting, very smooth, yet you may notice that the input shaft bearing is much louder. With the GL1 it is kept very quiet. I tried it for a year or so and went back to the GL1. Immediately quieted down. No NAPA in your area that will get it for you?

[geospider]

Thanks for the Napa suggestion. yep, they have it and $14/gal not bad.
Even our local, "more mechanic" driven store vs Oreily and autozone didn;t have it.
hadn't thought of Napa. only a few around now.

[BSmith79]

How much do you need to fill the diff, also the gearbox?

Thanks

[RRoller123]

Diff: 1.4 Quarts. BUT! You will not get that much in on level ground, it will start to flow out at about 1-1/4 quarts. No idea why, but the spec is apparently wrong. I tilted my Spider back a couple of years ago to get the small balance in, no problem. I did this because when I checked the rear seals out when I first bought the car, there was no fluid in the axle area, i.e. none coming out to the end of the axle at the seals at the hubs. Pretty dry. So I figured that is why they want you to put the little bit extra in, it gets a small amount out along the axles when you turn, incline, roll, yadd yadda yadda. But a few months later the rear axle seals perished. Not saying it was a direct response, but I now just fill until it overflows on level ground. And the rear seals are still fine.

Trans: Manual 1.75 Quarts NON-EP! Automatic: 3.0 Quarts.

[Gerrit]

I had the same problem but the numbers are correct but when you just remove the drain plug of your transmission, there will still be 0,5 liter left in the back of your transmission housing. to drain that too there is al little square bolt further to the back. you have to remove that one to get the last oil out. ( I learned this from my mechanic who is specialized in the 124 spider)

[RRoller123]

We did this on my '80 while it was in the shop, up on a lift, and pulled the rear diff plate and sprayed everything out to clean it, and it STILL wouldn't hold the whole indicated amount. Where is the small drain plug you mention? It is not on the cover on an '80. Now I am curious. Maybe the later cars had this?

EDIT: My mistake, I think you are talking about the transmission? Yes! There is a small plug back there, square if I remember correctly, that holds a few ounces behind an internal baffle or casting wall or something. But the differential, that is just one of those Fiat mysteries...

[Gerrit]

Sorry my mistake i thougt you ment the transmission. Didn’t read properly.

[SanJoseSteve]

I made the short drive from san Jose to the Tractor Supply store in Gilroy to get my transmission oil. They sell it in a 2 gal container for just $20. -Steve

https://www.tractorsupply.com/tsc/produ ... luid-2-gal

[PhillySpider]

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=

That Amsoil link for the syncromesh says 5W 30!?

[RRoller123]

Sorry my mistake i thougt you ment the transmission. Didn’t read properly.

No problem, if mistakes were nickels, I would be a millionaire!

Pete

[RRoller123]

BTW, not to get too far off topic... But Amsoil sponsors "Engine Masters" on YouTube. There are dozens of videos of various engine header/Carb/Exhaust, etc. configurations on test beds, and soaking it all in is like studying for a masters degree in this stuff. Well worth checking them out!

Pete