While the work on Rusty is preparatory to working on Dad's truck, it probably deserves its own thread, so here goes.

And, in case you don't know what Rusty is, he's an '81 F150 351M w/an NP435/NP208 combo. Yes, he's a 4x4 but he wasn't originally. In fact, judging by the way the floor is cut I'd say he was originally an auto, although he does have a manual steering column and instrumentation.

I bought Rusty because he has a recently built 351M w/an E'brock intake, Holley carb, and some kind of an aftermarket cam. And, there are other goodies. But, he was said to have a bad clutch, which was the reason the guy sold it cheaply, and it does make an awful noise when you let out on the clutch.

So, today I rolled Rusty into the shop and started taking him apart to get to the clutch. When I pulled the drive shaft I was reminded that when I got Rusty home he leaked diff lube on the driveway, and that seemed odd since the PO told me he'd just had a new pinion seal installed. Well, when I got the driveshaft off I tried spinning the yoke to see how much slop is in the diff, and discovered that the yoke moves after the slop is out of the diff.

Well, on to the tranny. The FSM says the first step is to take the shift levers out, but I couldn't get the one out of the transmission. So, guys, what's the trick on the NP435? In any event, I did get the tranny loose and ready to come out but not until I get the shift lever out. However, that did let me look at the clutch from the side and at first blush it looks like it has plenty of material on it.

So, now I'm wondering if the grinding noise is the yoke on the pinion and not the clutch. Hopefully I'll figure that out tomorrow, but another question is what is wrong when the yoke moves in relationship to the pinion? Is it just loose? Is the pinion ruined?

More on Rusty later.

 

Well on the pinion yoke...should be splined on there so if it's spinning then can only be 2 things....splines are stripped or just not engaged. Not sure if that's a 9" or 8.8"....not real familiar with either but on a chevy 10 or 12 bolt...the seal is part of the casing and seals the OD of the of the yoke as it slides over the pinion spline. The ID of the yoke (where the spline is) is sealed by the washer and bolt that holds the yoke to the pinion...normally put some rtv on there to help it seal. If it wasn't engaged all the way, that may explain why ist's slipping and leaking...not torqued to spec.

Does it go when you let the clutch out? Can't believe you can spin it by hand yet it would still tranfer enough torque to move the truck?

As for the clutch noise...you state it only makes the noise when you let the clutch out....is this while the truck is moving or does it do this standing still in neutral? If it everytime you let the clutch out, regardless of if the truck is moving then I would suspect a Throw-out bearing. Under pressue it might be tight but released it makes noise. I've had noise throw-out bearing when the clutch is released before.

Not familiar enough with the NP transmissions to help on the shift levers. Had one in my 78' F250 but thankfully never had any problems with it....Love it...wish I still had it

 

I wonder if you are right, and it's not the clutch at all but the rearend yoke slipping on the splines when power is applied to get it moving. How hard would it be to slip it back together and run it without the rear driveshaft hooked up? You can run it around in 4x4. That would prove out the clutch and the tranny.

 

Yes thats a good idea Franklin. Sounds to me like the pinion splines are stripped as well as the yoke. Gary you might be in for some more 9" fun is what it is sounding like. The crappy part is if the pinion is screwed then the R&P will have to be changed as a set.

What ratio is Rusty?

 

Oddly enough, the leak seems to be past the splines, not past the seal. Which, if all of this proves out, probably means the splines have been ruined and the seal on the front is leaking.

No, it doesn't go at all when I let the clutch out, it makes awful grinding noises so you push the clutch back in very very quickly. I found this issue when checking the slack in the diff and noticed that the yoke turns a bit more than the pinion. And, the truck is on the lift so I can see the tires and they don't turn then either so I know the pinion isn't turning that last little bit the yoke does. But, I can turn the pinion and the rear tires by hand via the yoke, so it does transmit at least that much torque. May have to bring the park brake on and see if I can turn the yoke, maybe with the u-joint u-bolts back in and a pipe through them.

Makes no noise in neutral.

Well, the only thing keeping the tranny and t-case under the truck is the fact that I can't figure out how to get the shift lever off. IOW, the tranny & t-case are completely disconnected and sitting, precariously I might add since there is no reasonable balance point for them, on the tranny jack. However, all of this effort won't be for naught even if it is the diff since I want to check the size of the flywheel, clutch, and pressure plate as well as various dimensions in prep for the ZF5 swap. Anyway, driving it under front wheel power isn't possible at the moment.

Yeah, I've already come to that assumption. Still need to verify it. And, still need to get the shift lever out. As for the diff, it is supposedly 3.50 - at least that's what the tag on the front diff says.

 

Let me check across the street for a used set. I posted the shifter stick question on FSB. Hopefully sometime soon there will some good suggestions.

 

Good idea on the pumpkin/jackpot/pig. But, I won't know until tomorrow if it really spins w/o the tires turning.

As for the shifter, thanks for posting it on FSB. Should be an easy thing to do, but nothing has worked for me.

 

James said if you still have the tub of used parts bring it by and he will put all of that stuff back in the old carrier and you can use that one for Rusty. Or even bring the one from Rusty and the used tub o crap and he will use the best parts of the selection for the rear end.

P.S. those rear ends were 3:50's also werent they?

 

Getting the stick shift out is done by either pushing down on the cap, and turning it ~1/4 turn, OR by unthreading the cap. I cannot recall which method is for BW and NP......

Kick trans into any gear, and make sure transfer case is not in neutral. Try spinning the output yoke on the back of the TC with engine off.

Did the unusual noise come from the trans/TC area, or the rear axle?

 

Here is what Steve83(big time Ford Guru) at FSB had to say about it Gary:
I will be looking in his album and trying to post some of the pics and instructions from it here shortly.

 

Found several threads on removing the shift lever. Here's one: https://www.ford-trucks.com/forums/8...r-removal.html

Now that I have the tranny sorta out and almost hung up on the shift lever getting it into neutral may be fun. But, all the threads say that's the way to do it, so I'll try it tomorrow.

And, for posterity, my suggestion for others wanting to pull an NP435/208 combo is to do it the way the factory manual says - first drain and then pull the t-case, then pull the tranny. The problem is that the balance point for the combo is in a weird location and you can't put the tranny jack there. And where you can put the tranny jack, which is under the tranny itself, leaves the t-case hanging in the breeze and putting a lot of pressure on the tranny jack as it tries to tilt it.

So, I'm planning to separate the two when I get them out from under the truck and then go back with them one at a time..

 

See if this linky works:
1983 Ford Bronco NP-435 Swap pictures, videos, and sounds | SuperMotors.net

 

Thanks. But, what he doesn't tell you with the lightbulb analogy is that they installed a valve spring behind the lightbulb. Some of the guys are saying it is almost a 2-man job.

 

Well I suppose that would be bad if it came off while you were driving down the road.

 

It's not quite a two man job, but you do have to put some weight into it.
I wrapped a rag around the base of the shifter (on top of the retainer) to give my fingers some protection.
Being in neutral for removal just helps with reinstalling later, when the shift forks are difficult to see down through the tower.

Push down HARD against the spring, then rotate the retainer anti-clockwise about 1/8 turn. It will pop up & the shifter, spring & caps will come out together.........EASY!!

Then, when you get the 435 out, I would personally throw it in the diff parts tub (no offense, Gary!). I really don't understand the choice of ratios Ford used in these.
Dodge & GM also used the NP435, but with much more practical gearing.

But - I'll get off my soapbox now