4-speed fluid

Reply Subscribe

Thread Tools

Search this Thread

Feb 1, 2011 | 02:20 PM

1977F1504X4AUBURN

Thread Starter

Junior User

Joined: Oct 2010

Posts: 75

Likes: 0

4-speed fluid

What fluids do you guys use in your manual 4-speeds and NP205?

Feb 1, 2011 | 03:40 PM

78 PEB

Cargo Master

Joined: Oct 2010

Posts: 2,674

Likes: 16

From: Ideeho

Gear oil.............I have used 80W90 as well a 85W140 successfully..........no real preference........

Feb 1, 2011 | 04:45 PM

fordman400

Senior User

Joined: Oct 2003

Posts: 161

Likes: 0

From: wisconsin

I use lucas 80w90.

Feb 1, 2011 | 04:56 PM

wyckedcombo17

Posting Guru

Joined: Sep 2009

Posts: 1,159

Likes: 1

From: Suburbs of Chicago

I use Valvoline 80w90 conventional gear oil for both. I prefer conventional anything over synthetic for these trucks.

Feb 1, 2011 | 05:03 PM

HIO Silver

Fleet Owner

Joined: Dec 2009

Posts: 20,678

Likes: 83

From: NorCal

Valvoline 80w90 gear oil in the NP435 and NP203. Smelly sulfur stuff!!! Wear latex gloves if you can...

Feb 1, 2011 | 05:27 PM

4x4 Bart

Fleet Mechanic

Joined: Feb 2007

Posts: 1,326

Likes: 48

From: Middle TN

I'm running Mobil One Synthetic Gear Oil LS 75W90. This shifts much better in cold weather.
The original factory fill was 50w motor oil, to be topped off when needed with 90w gear oil????

Feb 1, 2011 | 06:08 PM

1977F1504X4AUBURN

Thread Starter

Junior User

Joined: Oct 2010

Posts: 75

Likes: 0

Synthetic or conventional? I live in the Pacific NW so it rarely gets in the 90's in the summer and it rarely gets below freezing in the winter. Write now second gear can be a bugger to get into, especially when a Lexus is crammed up my tail pipe at a stop lite. It drives them nuts when I'm trying to find a gear. Puts a smile on my face.

This Hennessey Takes the Expedition Tremor's Off-Roading Capability to the Next Level

Verdad Gallardo

Top 10 Fords at 2026 Carlisle Ford Nationals

Joe Kucinski

3 Best / 3 Worst Parts of Modern Ford Ownership

Brett Foote

10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches

Pouria Savadkouei

Every 2026 Ford Engine Explained

Brett Foote

10 Ugly Ford Trucks That We Still Kinda Love

Joe Kucinski

10 Things Every Truck Owner NEEDS (2026 Edition)

Michael S. Palmer

Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath

Verdad Gallardo

Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer

Joe Kucinski

2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)

Brett Foote

Feb 1, 2011 | 08:36 PM

Bullitt390

Certified Thread Hijacker

Joined: Aug 2001

Posts: 14,441

Likes: 60

Quote:

Originally Posted by bamaf150

My 1976 owners manual says SAE 50 weight for both the 4 speed and the transfer case, unless below 10 degs, then use SAE 30

That's egine oil which is equivelent to 70W90, or more readily available 80W90

Josh

Feb 2, 2011 | 01:58 AM

#10

tikkakoski

Senior User

Joined: Feb 2010

Posts: 252

Likes: 0

From: Tualatin OR

We just put 85w-140 in my buds np435 and np205. And it shifts sooo much better. But im pretty sure the PO had ATF in both... Fail lol...

Feb 2, 2011 | 10:09 AM

#11

1977F1504X4AUBURN

Thread Starter

Junior User

Joined: Oct 2010

Posts: 75

Likes: 0

I put ATF-4 in my Jeep's transfer case put ATF has detergents so I figured that wouldn't be good in these older trucks. I'll just through in some 80W90 and move on. Thanks for your help guys. I appreciate it.