Anyone seen one of these transmissions?

[rsh4364]

NP 440/ NP 883. It is a 4 speed manual transmission. With 4th being a. 73 od. Gm option code MY6. Came in 81-87 full size trucks.2wd and 4wd. The 4wd models were cast iron cases,2wd aluminum. About the same gear ratio in 1st and 2nd as a 700r4. Would be great with a set of 3.73- 4.10 gears. I am starting junkyard searches.

 

[Iceman3005]

Interesting, never new they offered that manual trans! So from what I have gathered, it was used in the blazer and the 1/2 ton pickups only. It was considered a light duty trans, not meant for towing or big block engines. Also the 4x4 is very rare, and parts are hard to come by for both the 2 and 4 wheel drive version.

 

[dependable]

I have one in a factory 1982 C-20 with a 6.2. It is cast iron, with the factory supplier Hurst shifer, the build code on mine is MM7. The truck is geared pretty high, not sure if it is 3:73 or 4:10.

I do not think it is a very good match for the 6.2. On the freeway it can/could get up toward 70MPH, but the gears are too steep to sustain that on any kind of a grade or pass much of anything, so you are often stuck in the slow lane in 3rd, in danger of getting run over (these days). There is also a spot between 2nd & 3rd where you have to rev pretty high or lug, if you are in traffic that speed, especially on a hill.

The truck is recently retired due to rust, and I'd sell it, but I do not have time to part it out right now. The main reason I don't just scrap the truck is the C code 6.2 is OK, with 80K miles, and the tranny, which is considered valuable, mainly to the street rod hobby, from what I gather.

 

[blueblaze]

I've seen the trans a few times, 2wd and 4wd, gas and diesel, only half tons though. Apparently the aluminum case units had issues with cracking and coming apart. Last one I saw was on a 4WD 6.2 K10 and the case was cracked, we JB welded it back, replaced the clutch and then sold it. Local trans shop says the OD isn't worth while, they say the 465 is a much better option although no overdrive. If you had a half ton with a decent small block, I'd say its probably okay. The trans was in older Dodge / Chrysler applications I believe. I'd stick with the sm465 and make it up with gearing or tire size.

 

[rsh4364]

I have been driving my 1009 with 33s and 4.56 gears for 3 years, any time I see the letters OD transmission in the same sentence as a 6.2 diesel I get excited. If only they were common. Almost the same gear ratios as 700r4.

 

[dependable]

I don't think there is anything wrong with these transmissions, its just that the torque curve on the 6.2 is too narrow for the gaps between gears with a high ratio rear end, and not enough torque to cruise on highway. The torque converter on the 700r4 fills in the gaps some, and a blazer is lighter than a C-20, so it might not be as bad. But if one was going to bother with the clutch pedal conversion and all that to have a manual tranny, something like a 5 speed NV-4500 would be a better choice, as well as much more common. I believe some people on this forum have done that conversion.

Edit: plenty of people have added beefed up 700s, or 4L80s to get an over drive gear, which is almost a drop in compared to manual conversion. Of course civilian blazers usually came with a 700r4.

 

[ken]

I had one of those about 20 years ago. In a K10 short bed with a 305. It worked great. You can still find them from rebuild suppliers online. They are not heavy duty but will give good service in a 1/2 ton.