Transmission Fluid and Differential Fluid Change

[KELMO]

Dang, the last time I bought Sta-Lube it was around $40.00. But then again, that was BBC era. (Before Brandon Came).

[Damnsun 720]

On 1/9/2024 at 1:18 PM, IZRL said:

I went with Sta-Lube 85w-90. $78.99 is the cheapest non synthetic I could find. 

You won’t regret it! We put the same fluid on my dads 81 and I don’t know how to describe it but when shifting it feels like I’m one with the 720. Smooth and it engages good well worth the money.

[IZRL]

On 12/29/2023 at 3:16 PM, Thomas Perkins said:

I use Redline MT-90,75-90 in my 85 Nissan 720 4x4.I use the pump at Harbor freight.9.99 for pump.Awesome pump.I/2 drive to remove drain plug.Takes a hair less than 2 quarts.Amazon has 2 quarts for 40.99 with free shipping.I got mine their.When I removed drain plug no metal.I never grind my gears.

Tranny, Transfer, and both diffs done ✔️. Everything went well aside from my rear diff having a few good sized metal shavings, and my tranny being a quart low 🤦‍♂️. That harbor freight pump is a must for this job, well worth the 10 smackers . I was about to order one of those pump-less hoses from autozone when I saw your post. Pump is the way to go for sure, thanks.

[datzenmike]

Be sure to clean the magnet off so you can look at it the next oil change.... in 30K miles

 

 

I use Delco synthetic. It shifts faster with the same effort, shifts much easier the first few miles when the transmission is cold. I noticed that it much less effort pulling it down into 2nd and 1st when down shifting. May be me but the shifts are click/click and maybe a little louder and clearer. Not complaining at all... kind of pleasing.

[IZRL]

1 hour ago, datzenmike said:

Be sure to clean the magnet off so you can look at it the next oil change.... in 30K miles

 

 

I use Delco synthetic. It shifts faster with the same effort, shifts much easier the first few miles when the transmission is cold. I noticed that it much less effort pulling it down into 2nd and 1st when down shifting. May be me but the shifts are click/click and maybe a little louder and clearer. Not complaining at all... kind of pleasing.

 

The odd thing is that with the old oil (quart short) it was easier to down shift to 1st and 2nd. Up shifting when cold was a bit clunky in 1st, 2nd, & 3rd. When it came up to temp all up shifts were good except 3rd.

 

With the new oil (sta-lube 85 90) all up shifts are smoother when cold, 1st and 2nd still a bit clunky but better. When up to temp all upshifts are smooth like butter. But down shifting to 1st and 2nd is worse than with the old oil so far. Not sure what condition the clutch is in. I'm going to bleed the clutch fluid tomorrow see if it helps any.

Edited January 11 by IZRL

[powderfinger]

I'll second Mike here. From my experience the Delco synthetic, which is what I have in my transmission, provides smoother shifts that the Sta-Lube. I saw a noticeable difference when I switched fluids.

[datzenmike]

The GL-4 80w90 is a bit thick and acts accordingly when cold. I avoid down shifting as a rule because it's over used for slowing down and that's not good. I found that you really had to pull it to get into 2nd and often you would feel the gears grind slightly and rev matching helped but again not really needed much. With the Delco it did down shift much easier and any grinding was much reduced.

[IZRL]

3 hours ago, datzenmike said:

The GL-4 80w90 is a bit thick and acts accordingly when cold. I avoid down shifting as a rule because it's over used for slowing down and that's not good. I found that you really had to pull it to get into 2nd and often you would feel the gears grind slightly and rev matching helped but again not really needed much. With the Delco it did down shift much easier and any grinding was much reduced.

At some point in the near future I'm going to have to replace the seals on the tranny by the looks of it. So ill definitely give synthetic a try after that.  The tranny seems to already have a small leak. Synthetic might worsen it and I want to delay changing the seals as long as possible. I do occasionally slow down by down shifting, it's just habit. I'll have to stop doing that hahaha 

Edited January 11 by IZRL

[IZRL]

On 1/11/2024 at 7:14 AM, datzenmike said:

The GL-4 80w90 is a bit thick and acts accordingly when cold. I avoid down shifting as a rule because it's over used for slowing down and that's not good. I found that you really had to pull it to get into 2nd and often you would feel the gears grind slightly and rev matching helped but again not really needed much. With the Delco it did down shift much easier and any grinding was much reduced.

 

Found out why the shifting was a little wonky before. My Clutch Master leaked out all the fluid a few days ago so I replaced it. The next day when I was going to bleed the system I noticed that the Slave had just started leaking as well. So I swapped the Slave and bled the system. The truck feels like a whole different animal. It shifts like butter now. The slave must've been going out for a while. The old one never leaked before but now that I've replaced it. I can tell the new slave rod pushes further than the old one. Both new parts are Autozone. So I'm just gonna have to keep in mind that I'm gonna be replacing them about every 6 months for the rest of my days 😆.

Edited February 15 by IZRL

[Thomas Perkins]

Autozone's slave cylinders don't last long but they have a lifetime waranty.I just replaced mine.They rust bad too.Did you know if your slave cylinder leaks out you can fill it and bleed it to get home.I did it before.I have a one man bleeder kit.

[datzenmike]

Was likely the slave all along so save the 'old' master and most especially if it was an original Nissan master as the replacements these days aren't very good.