NP435 swap

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May 2, 2013 | 08:37 PM

Cdouglas18

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5th Wheeling

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NP435 swap

I recently bought a 1964 F250. The previous owner swapped in a 360 with an NP435. I've had it for only a couple months and it's been great, but I just lost 2nd and 3rd gear. As much as I like the np435 I top out at about 45mph, so I'd like to swap it for something that will provide a bit more drivability. Any suggestions? I should add that the rear end is spicer/Dana 4.10 and I plan on doing a bit of heavy towing. Any tips or input would be great. Thanks guys!

May 2, 2013 | 09:26 PM

1972RedNeck

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From: Townsend, MT

How do you top out at 45? My truck with 4.10's and the 435 will go 90.

May 2, 2013 | 09:45 PM

Cdouglas18

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Hmm that's a good question then. There's no tach but but the rpms past 45 are really high.. If I really push it I might get 50, but it's maxed there.
I wouldn't be opposed to rebuilding the 435 if I could get a decent highway speed.

May 2, 2013 | 09:56 PM

garbz2

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From: Glendale Arizona

Unless you install an overdrive the NP is a 1 to 1 final drive like all other non OD units.

Garbz

May 2, 2013 | 11:02 PM

SuperSabre

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From: Tucson, Arizona

Since you're talking about a nearly 50 year old truck which no longer has its original engine, maybe the differential gears were also swapped out to, say, 4.56s? Are you sure your speedo is accurate? Tachs don't cost much and are easy to hook up - then you'll know what you're really turning. Someone may correct me, but I think stock 360 2 bbls are pretty much done winding by about 4800 - 5000. Too bad you don't live in Arizona - I have a surplus NP435 available. Good luck!

May 3, 2013 | 07:06 AM

1972RedNeck

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From: Townsend, MT

Quote:

Originally Posted by SuperSabre

Someone may correct me, but I think stock 360 2 bbls are pretty much done winding by about 4800 - 5000.

And if you wind them that high in 4th with 4.10's you'll be over 100.

May 3, 2013 | 08:51 AM

Cdouglas18

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So if the rebuild doesn't solve the prob then there is another issue that ill need to address regardless of which trans I have in there.

Thanks for all the quick responses I appreciate the help

Chad

May 3, 2013 | 09:45 PM

110

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sorry that was the wrong post

May 3, 2013 | 10:57 PM

#10

NumberDummy

Ford Parts Specialist

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From: Simi Valley, CA

Quote:

Originally Posted by 110

AXLE code stamped on the Warranty Plate, located on left door face below the latch.

F100 9" ID tag located at approx. 5 o'clock under one of the bolts that retains carrier to housing.

May 3, 2013 | 11:03 PM

#11

110

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Thanks ND!

Jan 22, 2014 | 07:53 AM

#12

Cdouglas18

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Thanks for everyone's input on the 435. I know it's been awhile now but I wanted to give some resolution. I ended up rebuilding the np435 I had. The synchro was dust- literally pulverized like mud in the bottom of the trans. The problem with the high rpms at low speed was a problem with the transfer case. I was able to move the shifter but it was never actually coming out of 4 low.
Thanks for all the help