My D100 pickup has a three speed manual transmission and I want a four speed. My factory manual says they made an "overdrive-4" transmission. It also mentions a 4 speed manual transmission. What's the difference between these two? Will either work in my pickup? It has a 225 engine.

In the junkyard today, the guy said he had a 78 Dodge 4 speed mnaul transmission. I asked about an overdrive-4 and he said they didn't make that transmission for my truck. I know they did because it says so according to my factory manual. The guy wasn't very pleasant and wouldn't listen to what I said, he just wanted to show me the four speed. Which brings me to another question: Since I know next to nothing about transmission, how do I identify the one I need? I couldn't trust this guy, I figured he just wanted to sell me what he had.

The OD-4spd will work in your truck, howmuch mods it will take to get it to work is resting on what you currently have bellhousing wise.

the original non OD 4spds were cast iron and heavy buggers to boot and were made up untill 70 (?) then they were replaced with the iron OD-4spds, then later on the Aluminum OD 4spds came intoplay. you may want to check out Doc's "4spd Transmission" article in the Articles section on this site, its very well put together and should awnser 90% of your questions.

Justin

a little more information:

I consulted my service manual and scooted under my truck. I have the 390 transmission on there. The manual says there's the overdrive-4, the 435, and the 445-D four speed transmissions. The 445-D was available as extra equipment on all light duty model trucks. "It is a rugged, smooth, exceptionally easy shifting transmission. All gears are helical." So says the manual

Anyone have experience going from a 390 to a 445-D? I wonder how difficult it is.

When I had my 79 D-100 shortbed, it had a /6, 3 on the tree. The shift linkage wore out in my column, found another in the yard. THAT one went to hell, and I put in an A833 OD ("Overdrive-4"), short tail out of an F body. It was the 1st 833 OD that came along at the time, and I NEEDED my truck. Bolted right up, mounts are in the same spot, regardless of tailshaft length. I had previously switched to an 8-3/4 out of a '69 truck
(FYI; went right in easy as could be, only difference was the donor truck was a long bed to my short, E brake cables were too long a blue wrench took care of that). I had swapped my mom's '84 Fifth Avenue's rear from a 7-1/4 to an 8-1/4 and had to swap to a shorter driveshaft. The old driveshaft out of the 5th Ave (318, 904,7-1/4) fit my shortbed D-100 with the /6, short tail A833OD, 8-3/4 perfect! Needed a longer one cuz the 3 speed was a long tail. The 8-1/4 (8-3/8??) originally in my truck blew up without much effort, 8-3/4 never missed a beat! Neither did the A833OD, both stood up to more than they should have!

I know a yard that has a NP 435, and an A-833OD truck setup for sale, kept safe in their warehouse for a decent price. I also have an A-833OD truck setup with the shifter and linkage all intact....If you were local I'd get you hooked up.

-D.Idiot