Hey all, I've spent a lot of time lurking and searching and fixing things based on others posts, but was hoping for some more specific advice this time around.

1974 F350 DRW 360 NP435 with Hydraulic dump bed (so I use the PTO)

I recently picked this thing up knowing there were tranny issues, but I'm not sure where to take it next.

Granny 1st and second gear work just fine other than the slipping clutch. 3rd works, but it will pop out of gear when decelerating if you don't clutch it because it will start bouncing. 4th gear doesn't work at all. Horrible grinding if you try and put it in. PO said it used to go into 4th, but would pop out unless he held it in.

Other than this, the thing leaks like a sieve. It is just caked in oil and leaves some nice spots even just overnight. There's so much oil that it is impossible to tell where it is coming from.

This NP is also incredibly loud unless the clutch is pushed in. I know 1st/reverse should be loud, but it isn't much quieter in any other gear. Almost roaring loud. In reading other posts some have mentioned perhaps bad bearings causing the noise?

With all of these problems/concerns would rebuilding it be a reasonable thing to do, or should I look for a junkyard replacement? I'll probably pull it before I decide, but when I do what should I look for that would make rebuilding it not worth it? In doing some reading they seem to be regarded as bulletproof, and if getting a rebuild kit and plugging through it is what it would take I'm ready to go that route. Just don't want to throw good money at bad.

Thanks!

 

I've got a couple extra NP435s if you want a parts one or another used one to try out or rebuild (can't promise they work perfect but they don't leak and aren't locked up)!

Can't help ya with your problem tho, I'm still learning about them too!


(Saw you're located in IN, I'm in central Indiana but frequent southern Indiana quite often)

 

Third sounds like syncros or maybe hard part's like gears and so forth and so on. They are very easy to rebuild but when it comes to hard part's I'm not sure what the cost is, only ever had to put bearings and syncros in ,So if you can find one that shift's and acts responsible and you should be able to.Go with it and refresh it with bearings and syncros. Also maybe throw out bearing and pilot bearing could be making some of the noise.

 

I'd go with fordguy's offer!

 

Hey, they can't be any worse than what I've got. I work in Indy so we are super close. I can't message anyone for 10 days since I just joined, but you can find me at https://www.facebook.com/sean.fil and send me a message on there!

 

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Watch for cracks in the front cover, pretty common prob but new one's are available.

 

There are nylon inserts on the NP435 shift forks 1/2 is different than 3/4. Overtime these wear down, could crack apart, pieces fall into the gears, where they may jam them up.

Popping out of gear is caused by worn synchro brass blocker rings. NAPA and etc auto parts stores have all the parts that are also available NOS

The 'spring loaded' shift lever retainer cap (B8T-7220-D) has two notches, it's retained to the shift tower with two pins.

To remove this cap, place lever in neutral, then the cap must be pressed down by hand and held down while turning it counterclockwise to remove it.

Clueless people use pliers or channel locks to remove it, which tears out one or both of the notches. Not pleasant because now they aren't going anywhere until the puppy is replaced.

 

Well, for better or for worse I found what has to be part of the problem. The transmission only has 2 bolts holding it in! And they are half backed out. I couldn't get any pictures of the other side, but its in the same condition. As you can see it's leaking oil like crazy. I went to the top side and took a video of all the slop. Everything in there is wiggling all over the place.


So, now throwing this into the mix, what all could have gotten trashed while driving around like this? Input shaft? Something on the bellhousing/motor side?

No idea how long the previous owner drove it like this. I did a quick 2 mile test drive before deciding there was definitely a real problem.

 

For what it's worth I just had a good transmission shop put a Novak kit with new synrco's in my 435. total cost about $850. it's tight, quiet and leak fee but I have to say I'm not impressed with how it shifts. they tell me it will smooth in with use but I'm not sure. moral of the story, if you can find a good one you may be better off than rebuilding one.

If mine doesn't get better I'm going to swap it with one of my farm pickups that shifts perfectly.

 

In case anyone happens across this in the future because they are having a same or similar issue, the tranny being run not properly bolted up trashed things to the point where it will cost quadruple in hard parts than just buying a used one locally.


Heres a video of the slop in the input shaft and the resulting damage to the input gear and the gear below it. There was also damage to 1st gear which just added insult to injury. I don't believe it was related, but rather just 45 years of grind em till you find em.

I already have the rebuild kit, so I'll find a used one and rebuild it and hopefully get another 45 years. Thanks all for the help

 

We rebuilt my son's NP435 which was having some of the same issues. We spent the money on a high-quality complete kit. We also, replaced the clutch plate and flywheel while we were in there. Shifts like a dream now. The NP435 is a tank of a transmission.

 

Yeah, I was hoping to be able to do the same. I bought a high end rebuild kit, but I have 3 trashed gears, so it's a no go.

 

Sent ya a pm! Meant to message you sooner but lost your thread