I'm an import mechanic, new to Fords, just bought a '73 P400 with a 300 six and an NP435.

The trans had a nasty leak from the output seal, lost about a third of its oil before I fixed it in the seller's driveway. I drained the oil and found modest metal shavings on the magnetic drain plug, not a lot and no chunks. I then drove it without incident about 100 miles on the freeway, at the blistering pace of about 45mph

How loud are these boxes normally? The trans makes a *lot* of noise by my standards (BMW and Toyota, mostly), different in all gears. Countershaft whine is one thing, but what concerns me is that fourth makes both a prominent howl and sometimes an extra noise, a dissonant mid-pitched half-grind-half-whine. Both noises vary with speed and load - about as loud decelerating as accelerating, less when doing neither. The howl is there always; the extra noise comes and goes.

I haven't checked for metal since the drive and new noise; will do that very soon.

There's very little noise in neutral with the clutch out. This leads me to believe that the output bearing is the main source of noise. Does this sound right? I've rebuilt a couple of manual boxes but am far from a transmission expert.

The frontmost U-joint is slightly loose, and the CSB is slightly loose in its housing, but not torn. There's some vibrations that I feel through the seat, not really through the shifter.

This thing has a Bendix driveline brake. Can I assume that if the output shaft bearing takes a proper dump, that I will feel the driveline brake drum binding on its shoes as the output shaft goes out of alignment? What else am I risking by driving it in fourth for a while?

It came with a spare T18. I searched and found that the bellhousing pattern is the same. What about that driveline brake; will it fit?

I need to drive it about 500 miles home through some desolate highway. I do have tools and roadside assistance. Assuming I find the oil metal-free, should I wing it, maybe with a spare output bearing? Or play it safe and either rebuild it entirely or replace with the T18?

 

You probably have a bearing going out in the tranny. If you have rebuilt other manuals, this one shouldn't be an issue. Bearing and seals kits are pretty cheap for it.

 

That does sound like an output shaft bearing, fill it with straight 140wt gear oil and you'll be fine for the trip home. But if you can I would fix that u-joint, and replace the carrier bearing. That vibration is probably what killed the bearing.

As far as the T18 goes, the driveline brake won't fit, not easily at least. And unless the t18 was out of an HD truck (which is doubtful because it doesn't have the parking brake) the bell housing pattern may actually be different. For whatever reason, the HD 4spds use a different pattern, 3 bolts line up but the 4th is in a different spot entirely.

Where are you at? If you don't want to rebuild it I know where there are 3 or 4 of these gear boxes sitting in storage.

Sam

 

Sam, I am in Seattle at the moment, and need to get back to Missoula. Three mountain passes and the desolation between Ellensburg and Spokane (no, Ritzville does not count), then more desolation after CDA.

Got three U-joints (Chinese garbage that somehow costs more than Japanese GMB, but I'm in a hurry...), will replace tomorrow morning. The CSB turns smooth and quiet. With a small spacer between its top edge and the frame crossmember, it behaves like a good normal one.

I don't mind rebuilding it, just not now if I can possibly avoid it. It's parked on the street near downtown Seattle outside a friend-of-a-friend's house. I understand these can be rebuilt using not much more than a rock and a big stick, but the conditions are not optimal to say the least.

Good warning about that T-18 on both ends. Sounds like it's useless to me, then. Trade you it and some beer for a 435? Seems I can't send you a PM yet.

Having spent a few hours between parts stores and a Ford dealership, the best-seeming advice on oil I got was from Novak's website, which suggests that a conventional 80W90 GL5 works just fine, so that's what I put in it (what came out smelled and looked similar, not ATF anyway). Synchros work great. Should I still bother with 140?

 

I'm in seattle too, can you post some pictures of your NP435? especially where it bolts to the bellhousing on both sides

The main reason i suggested the 140wt was to quiet that bearing a bit. The thicker oil can help injured parts live a bit longer, especially out on the highway. 80w90 is great for a lower mile or a rebuilt box, but I would put the 140wt in yours.

Let me see how much I can get one of those NP435's for, I don't have much use for a t18, but if you chip in a few bucks for gas i might be able to go check out and grab one of those 435's for you.

Sam

 

PM sent.

Dumphone here, so no pictures. I just pulled the drain plug. It looks like about half of this:



...except it's after about 100 miles, not 60k. When I drained the oil two days ago, it was about three times as bad and a lot less shiny. No chunks either time.

 

The mystery deepens. I just pulled the output bearing (piece of cake; screwdriver and a light hammering was all it needed)... and it looks fine, smells fine, and turns fine. Ever so slightly rough when given as much axial load as my hands can. Zero play. It's a Nachi 6308. Should I replace it anyway with an overpriced National one from the local store?

 

I would. Or order a cheaper bearing online.

 

Motion industries on 4th ave in georgetown can get you one for about $40

Sam

 

I'm also interested finding one or two of the NP435's, prefer a divorced transfer case version or a 2wd version. One with the larger 5.1" input bearing retainer size and one with the smaller 4.8".

 

Thanks! Motion Industries came through. I got that Nachi there at the last minute, installed it, topped up the 80W90. The shaving clump looked a lot bigger than it really was when I cleaned it off the plug. If the trans continues to make crazy noises I'll replace the oil with 140, otherwise short of a full rebuild there's nothing else to be done. After I check the diff oil (not leaking, but just to be sure) and replace tierod ends, I set sail and hope for the best.

 

They're a noisy gearbox even when in good running condition. I replaced the original one in mine for a rebuild and it was less noisy but the sound reduction was hardly noticeable.

 

The new output bearing and U-joints didn't make a huge difference if at all, but with a pair of earplugs, I made it! Will check oil again at some point, but if it drove 500 miles over mountain passes without incident, it'll do just fine for the occasional local trips that I need it for.

Got about 8mpg doing 60, 10.3mpg doing about 50.

 

Glad you made it man!! Enjoy the new truck

 

I'd like to see a picture of this "Bendix driveline brake"