My '79 F150 has a 351M with 4-speed manual---although the VIN info says I have an H2J! Anyway, how can I be sure I have the NP435? It's got a granny, and I know the differential is a 9" 3.50 TracLok (learned it from this place!).

Yesterday I was hitting an uphill on-ramp in 4th gear at a little over 30mph and attempted to gun it. The engine revved just fine! But the transmission was having nothing to do with it. It wasn't until I lowered my RPM's that it started accelerating. Is my clutch on it's way to greener pastures? I'm seriously considering taking the plunge and trying to fix it myself (gulp!), and I've gotten lots of good tips here for doing so. (renting tools/floor jack, etc.)

Also, there is an odd noise/vibration in 3d gear that doesn't exist in any other gear, and it's got me concerned. I don't spend a lot of time in 3d gear, as a result. Should I be concerned, or is this within the tolerances of "normal?"

By the way, I've read a THOUSAND posts on here, using the search feature, and have learned an incredible amount. There is so much good information here! Up to and including what NOT to ask... ("what's the "M" for????" HaHa)

Note to newbies (like me), USE THE SEARCH FEATURE!!! I see the same basic questions asked over and over again, the same ones I would've asked had I not used the Search button.

 

This is a NP435 with the 2wd tail housing. the PTO cover is on the other side and the top cover is aluminum. The granny 1st is unsyncronized



This is a T18 without the tail housing. the PTO cover is on the other side like a NP435 but there are more reinforceing ribs on the case and the top cover is iron. The granny 1st is unsyncronized



This is a T19 without the tail housing. there are PTO covers is on both sides and the top cover is iron. The granny 1st is syncronized but a little higher gear then the T18 and Np435.

 

I have 2 '78 Fords w/300's, one with a NP435 and the other with the T18. Both have a growl and a very slight vibration in 3rd. I think the technical name for it is "Old Truck Growl" LOL. I think it's just the way they are.....Every other manual I've ever ridden in acts the same way.

How bad is your vibration anyways????? How many miles on your clutch??? Is it adjusted correct?? It should only have a 3/4" to 1.5" of freeplay in the pedal to be adjusted correctly.....

Lenny

 

Thanks for the information, it's an NP435 for sure. As far as how many miles the clutch has on it, there's no way to know. I got it a couple of weeks ago, and it turns out that the guy who sold it to me REALLY sold it to me. I'm in the process right now of replacing the unbeknownst-to-me holey fuel tank (the auto shop ordered the wrong one, so now it's apart until Monday... ). Anyway, the seller told me that the rebuilt 351m has about 40K on it, and hopefully there's some truth to that part of the story at least. I've found slgns that it had been sitting for some time, and he didn't mention that part either. On the upside, it's a great project truck and will be very solid when I'm done---if being "done" ever really happens. Meaning I'll be doing this or that to it for as long as I own it, I'm sure, just to tweak it or polish it up.

I'll be checking the free-play to see if that's it, thanks for that advice. I see that the repair manual suggests the same thing, so you're right on. Fingers crossed!