Need help
5 23 75. 435 it's a 4 speed manual with a really really low first hear. Can anyone help? Thanks in advance
Does the shift pattern look like this ****:
Or is there even a **** to look at? If not, try shifting it in this pattern to see if that covers yours.
Can't think of a single manual transmission that would have a pan to check the pattern for. Those charts you see around are only for automatics.
Does yours still have the cover and shift lever? If so, I'm pretty sure most, if not all of the NP435's had cast-iron cases and aluminum top covers with a twist-on collar to retain the shift lever.
Good idea to change the fluid in it while you're messing around with it too. If you don't have a book yet, you can check around with members here to see what they use.
I think these rugged boxes can take anything from ATF (fuel economy) to 130wt gear oil (protection) but I like the appropriate synthetic version of a 75w/90 gear lube myself.
Flows well, offers the protection of a gear lube while being thin enough to shift easy in the cold weather an protect in the hot.
In case you were wondering...

NP435 = aluminum top cover w/8 bolts
T-18 = cast iron top cover w/6 bolts
Warranty Plate TRANS code: A = NP435 (N-1965 only) / F = Warner T-18 / P = F350 Warner T-19.
Warner shift lever retainer cap (8MTH-7220) threads on/off.
NP435 shift lever retainer cap (B8T-7220-D) has two notches, is retained to shift tower by two pins.
To remove this cap, it must be pressed down and held down while turning it counter clock wise to remove it. (Its spring loaded and twists into place, we removed one and it was a 2 person job. Put the trans into 2nd, 4th, or reverse, then one person holds the cap and applies pressure, twisting in a counter clockwise direction.
The other person hits it from the top with a hammer to get the cap to go in below the two clips that hold it in.) People unaware use pliers or channel locks to remove it, which tears out the pins.
Originally NP435: Reverse-down towards the seat while Warner T-18: Reverse-up towards the dash.
The reverse shift pattern was changed circa 1973, but I can't recall for which of these 4 speeds. ( I believe it the NP435)
Note: There's another 4 speed: RUG SR-OD Single Rail.
Block of wood trick to get the cap off and not tear out the pins.
I like the wood idea for sure! Next time...
Paul
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When I got into the industry back in the eighties we were calling it the "New Process Gear Division of Chrysler" when getting into detailed discussions. But they'd been in business a LONG time before Chrysler got into the act.
They also made the transfer cases that were THE mainstay of the big three auto makers during that time. NP205's and NP203's were the only two options for many of the years.
All the gear boxes were very highly thought of, and are still highly sought after by some.
Your trans is not the most street friendly perhaps, but it's still one of my favorites. I like it because it's a simple, strong and super reliable unit, with a very simple "truck-like" attitude. Not as well heeled as a more modern gearbox for sure, but it's what we expected to be in a truck back then.
No synchro shifting in some gears? Check.
Anything but quick shifting? Check check.
But it could be used, abused, and shifted without a clutch easily once you got the hang of it and the size of the components alone practically guaranteed a long life. Yes, you can break anything if you try. But these needed you to try pretty hard if you really wanted to get one to complain.
Hope you like it in yours. In spite of it not being the most modern out there.
Unless you want an overdrive at some point. In which case maybe an NV4500 (New Venture Gear) or ZF-5 from a Ford would work better instead.
Paul
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