I've got an 85 E350 with a f250 4wd frame and the 300. I have searched all over these forums and the 300sixperformance forum and I haven't been able to find a useful guide or any threads that would help me figure it out for sure.
Its a 4 speed manual (not sure if fourth is OD or not). It seems to be geared low but I'm not sure on the diff gearing so I can't say for sure. It has an aluminum shift tower and cast iron case. I have found numbers on both sides. The side opposite the starter has a 3 above 15795. The side with the starter has C12A then NH 84 below that and then C (or G, hard to tell) -13894-1.
The starter is on the passenger side. Someone had painted on 79 F150 4x4 as well. It has a hydraulic clutch.
Any Ideas?

These are the problems I'm having with it. Shifting into first is rough and grinding unless I really take my time, shift halfway give it a couple seconds to "slow down" and then drop it in, shifting into reverse can be the same way. Also when rolling forward or backwards in first or R respectively, with the clutch all the way in, it seems to try to engage and will drag and lurch.
Shifting into second is fine unless going around a tight corner which makes it very hard and rough. Third and fourth are smooth and fine. It ldoes have a non-slip rear diff (detroit locker).
Thanks in advance for all insight and ideas!
Andre

 

Warner T-18/19 4 speeds: Shift lever retainer cap threads off/on. T-18 introduced in 1965 F100/350, T-19 introduced in 1979 F350 2WD

New Process 435 4 speed: Shift lever retainer cap has two notches, is retained by two visible pins that protrude from shift tower.

Hydraulic clutch first introduced in 1983 F250/350 with 6.9L diesel & 460, 1984 F150/350 w/300/302/351W.

 

New Process 435! Thank you very much!
continued reading, seems like synchronizers could be the culprit for the rough shifting.

 

I have the t18 myself. These transmissions last forever..so much that slop comes with the shifter. The t18 and np435 are almost identical with a few exceptions..but are very easy to rebuild and freshened up. I have a lot of playin shifting mine..that's cuz the groove the metal pin fits in gets worm out and loose. I'm sure any tranny shop would rebuild it for ya or heck..ya might be able to yourself

 

First and reverse grind because they are non-synchro.

Run it into 3 or 2nd before you engage 1st or reverse, making sure you are stopped first.

Your cornering sounds like typical clunk and chirp Detroit Locker.

 

His locker would explain somethings..but the np435 differed from the t18 in that the 1st and reverse WERE synchronized. I can understand on a t18 have difficulty at times cuz they're non synchronized..but on a np? Something else is up

 

T19 is a synchro first, no first gear synchro for the NP435 or T18.

 

Thanks for the clarification I thought since the np had the synchronized reverse it had the synchronized 1st haha. Anyhoo...these trannys are really just 3spds with a low pulling gear. It's a pain to start in first cuz they're so low geared unless you have a large load. Most the time I start in second gear and it does just fine. The 1st gear just ain't practical until you have a large load. Try driving w/o the 1st gear..start in second and see how it does. I'm sure thatll make a bit of a difference

 

And as for the lurching..its cuz the 1st and reverse are low geared. I had the same problem until I leanred to drive the 4 speed haha. The t18 has a 6.32:1 ratio 1st gear and the np is even lower..so trying to give it a lot of gas will cause it it grab and stumble a few

 

Well alrighty then This is excellent news! Thank you all very much for the clarification. The only other odd thing about it is a clicking/ticking that starts around 45 mph and seems to come from the transmission. I'm pretty sure it hasn't always been there but maybe I'm crazy. I can't feel any abnormal vibration but the noise is quite audible.

Just out of curiosity any ideas on how much a rebuild from a shop would be? I'm fairly mechanically inclined but I probably won't ever have enough down time to figure it all out myself.

 

The ticking is normal. Mine does it too. Just be sire to check your gear oil ever now and again. Rebuild kits are in the ball park of 150-200 bux. A shop would probably charge you 5-700 bucks to rebuild depending on labor costs..could be more though..as I know a typical rebuild for a newer type transmission can range from 1300-2000$