Hi Guys,
Well, if all goes well, my '72 F350 will be picked up by the Transport Co. today, and be home tomorrow.
One of the things that we'll be doing to it is installing a new Clutch (w/Pressure Plate & Re-Surfaced Flywheel).
It has the NP 435 Tranny (4 Speed w/Granny Gear).
Since we're going to have the Transmission out - I definitely want to change the Fluid.
What kind of Transmission Fluid goes in one of those?
How much does it take?
Has anyone here ever done a Fluid Change on one of these?
Thanks.

Below is "Mr. Green Jeans" waiting to be picked up.


Ford Truck in yard Finland.jpg

 

https://www.novak-adapt.com/knowledg...ual/np435.html

These guys are helpful and provide some useful info. I use 50 weight motor oil in my NP435 as recommended in the 1965 owner manual. It's actually thicker than 80-90 weight gear oil but seem to work fine. Main idea is to not use hypoid gear oil or oil with high zinc content---aka ZDDP containing--- (for flat tappet engines) due to corroding non ferrous transmission parts.

It takes 3-4 quarts...can't remember for sure.

Couple tips on swapping clutch. I use a tranny jack or motor cycle jack to lower and lift the tranny. They're around 140 lbs. Also, the flywheel looks like the bolt holes are evenly spaced but they only line up one way.

 

Thanks so much for chiming in!
Really appreciate it - and the web site link.
I'm attempting to learn as much as possible about my "new" Truck.
We're actually going to be pulling the Engine/Transmission out together - doing all the work in a heated garage, then putting it back in.
(Actually putting a 390 back in it - w/new Clutch, etc.)
So.......50W Oil?
if you get the chance, let me know what brand, if you don't mind.
This really helps.
Appreciate it!

 

I would run a syn oil, you will like it better during the colder months, easier shifting. Plus it can take higher temp than std oils during the summer and high loads.

 

Still looking for some 50W Conventional Oil, but found this (below) at O'Reilly's. Looks like I could use this to (potentially) top off the rear end if necessary........

https://www.oreillyauto.com/detail/c...f-250?q=80w-90

(Novak site says this would be good).

An 80W-90, API-GL5 or MT-1 rated fluid is very good. Some claim faster shifts from using a 50W engine oil in their transmission and we do not consider this to be contraindicated unless you operate your vehicle in a very warm environment
An 80W-90, API-GL5 or MT-1 rated fluid is very good. Some claim faster shifts from using a 50W engine oil in their transmission and we do not consider this to be contraindicated unless you operate your vehicle in a very warm environment.

 

Thanks.
What they're saying on that Novak site is that partial synthetic is good - full synthetic may be a waste of $.
I don't know (and I admit it!).
This is all new to me.
I really don't care about the $ - if it's the best thing for the Vehicle.

BUTT.......they have a thing on there about towing with the 435 - I need to add a "Transfer Case" is I want to tow????
WTF???
I was unable to copy & paste it.
My F350 is a 2WD.
This would be a big problem if I can't haul my hay trailer!
Anybody know anything about this???

https://www.novak-adapt.com/knowledg...ual/np435.html

 

I got a case of Valvoline 50w on Amazon.

 

50w is normally a racing oil.

Transfer case not needed unless you want 4x4. I don't know where you heard that it was required.

 

You do not need a transfer case. I didn't see anything suggesting that but I just glanced at it.

While these are a good transmission, towing heavy loads in hilly areas can be semi-miserable due to the gear spread with only 3 usable gears.

Another thing to note and Novak covers it--you can't flat tow without pulling the driveshaft. Unlike most manual transmissions, the 435 won't tolerate being spun in neutral without the engine running.

 

The amazon product is 50w engine oil not VR1 racing oil. The shop manual and service spec manual both show 50w for the transmission and transfer case for 1968 F100 4x4.

 

I use 50w valvoline I got on Amazon (link below). NOT the VR1 which is racing oil and has the ZDDP additive for flat tappets. I don't think you want ZDDP in an NP435

Heat was mentioned earlier. My tranny doesn't get above normal engine temperature even when towing so I figure conventional oil is "okay".

As mentioned, you do not need a transfer case to tow a hay trailer. Novak was warning you not to flat tow your truck in neutral because the NP435 can't lubricate itself unless the input shaft is spinning. If you ever need to flat tow your truck, just disconnect the driveshaft next to the differential and hang it up.

Also as mentioned, there is kind of a wide spread between 3rd and 4th gears. The problem persists in some 5 speed trannies as well where they have the same gear ratios as the NP435 but added an overdrive. I found with my 4.10 rear there were a few times I was limited to 3rd gear doing 40 mph (up hills) because 4th gear was too fast for towing in that scenario. I worked around that by adding a gear vendor which splits the gears. it's not a big deal but I don't think it was really over come until we got 6 speed trannies.

On the other hand, 1st gear in an NP435 is very handy for launching heavy trailers and crawling around a barnyard with a load.

 

Ford said to use SAE50 or SAE30 if you encountered hard shifting in cold weather. Any off the shelf non detergent oil should work just fine. The problem with any oil, other than racing oil these days is that it will have way less zinc and way more detergent than the oil that was available in the 60's and 70's. There is another option but a little more costly it will have some zinc but nothing else.
Buy AeroShell 100 Mineral Oil - 12 Quart Case SAE 50 Oil

 

Oh.......so I wouldn't want to Flat Tow MY TRUCK without dropping the Drive Shaft.
Thanks Heaven.
The way it was written, it sounded like you weren't supposed to Tow Anything without having a Transfer Case attached, or Dropping the Drive Shaft.
I thought, Darn, that makes no sense!
I guess it's just not good to Flat Tow your NP435 when n Neutral - it doesn't like that.
Whooo. I was worried.
Thanks Guys!

 

Okay......so how do these 2 look for the NP435 & Rear End Differential?
One is 75W-90. One is 75W-140.
Which is better?

https://www.oreillyauto.com/detail/c...0%2C+Synthetic

https://www.oreillyauto.com/detail/c...0%2C+Synthetic

Thanks.

 

I personally use Amsoil for all my lubricants, have been using it since the 80's. If the 75-90w is the right weight that's the one I would go for. You don't need the 140w. The first time I used Amsoil I changed all the drive chain lubs (dif ft and rear, transfer case, and trans) I gained almost 2 mpg in my jeep. I've been sold ever since. During extreme cold (30's) you will notice the trans shifts like it's in the 80's, smooth no stiffness.

The main thing about pure syn lubes is that they move more easily during cold temps and protect better during high temps and loads. I stay away from blends since they only need to add 3% syn to call it a blend. Which means the base stock is crude.