I am replacing the t-18 in my 2wd with a np435 from a 4wd. Can I just unbolt the tranny from the bell housing and replace the tranny without messing with the bell housing bolts, clutch, starter, etc? The 2wd t-18 is behind a 4.9 and the 4wd np435 was behind a 302. Also are there any good ways of telling if the 435 needs rebuilt or not? I notice the input shaft seems a little loose and don't know if this is normal or not.

 

I just rebuilt my NP435 in my 2WD '75 this past weekend. The input shaft should have some side to side slop in it. There should be about .010" end play in the shaft. I know it feels funny to be able to move that shaft around a bit, but as long as it's not touching the throwout bearing collar, it should be all right.
As far as knowing whether or not your tranny is good without installing it first is a crapshoot. Mine was leaking badly at the output shaft, the 2nd gear syncros were shot, it growled/howled in 3rd and 4th gear, and the shifter rattled real bad in 3rd and 4th gear. When I took it apart, I could find no obvious signs of wear or damage. I bought a master rebuild kit from bronco graveyard for $165, and it included all new bearings, syncros and seals. I replaced everything and put it back in the truck yesterday. The tranny now shifts like new, doesn't make any noise, the shifter doesn't rattle any more, and no leaks yet.
So i am very happy and quite pleased with myself. The local tranny shop said it would cost me $700 to do the same job if I removed and replaced it myself. It took me close to 2 days to do the entire job, but was well worth the effort.

 

did you need any special tools to rebuild the np435?

I was just quoted $700 too

 

The only special tools would be pullers for the bearings and races. I didn't have them, so I had to do some shade tree type stuff. A couple of the races i cut out using the dremel tool and cutoff wheels and/or carbide bits, just being careful not to cut the housings. Basically, the input shaft bearing and race were the most difficult. They took some time to get out. I tried the slide hammer bit, but they wouldn't budge. I had read in a post here where a transmission shop had used a welder to run a bead on the race itself - its a rather large bearing- and the race popped out. I didn't try that, I thought I'd probably end up with the race welded permanantly to the input shaft housing.
Other than all that, a decent set of feeler gauges and a dial indicator are needed to set the clearance for the syncros and the input shaft end play.
BTW, you can get the instructions for the rebuild at BroncoGraveyard.com in their tech section. I printed it out and along with an exploded view diagram, I didn't have any problems.
I also took pictures with the digital camera as I took it apart so I could look back at them during the reassembly, but it turns out I didn't need them. But I think they would have been good to have if i had found something damaged that needed replacement and would have delayed the reassembly - my memory just isn't that good

 

did the np435 have a married transfer case? if so I don't think that you can use it in a 2wd.

 

I just picked up a t-98/t-18 to replace my 3 speed....also snagged another bellhousing off a loose 3 speed....bellhousing from both 3 and 4 speeds are same...truck is 2wd w/352....bellhousing has same numbers....but as far as changing trannys....if you arent doing a clutch, leave b/hsg alone, if you are doing it alone I would pull bellhousing...makes bolting up the P/plate easier access. Just my .02
BTW, this is a 66 truck its going into, out of a 65. my 65 driver is an FE w/NP435....same bellhsg too............hows that for parts interchange


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