muncie sm420

[rudyyloverboiii]

My four speed is starting to go bad on my 64. Anyone swap it out with a 5 speed manual that not much modification or none of it was required. Thanks for the help I would really appreciate it.

[chevy_mike]

I did an AX15 5 speed swap, detailed here, http://67-72chevytrucks.com/vboard/s...d.php?t=475370

[par4tom]

I did an NP440 swap for my 420. It has overdrive and there is one for sale on ebay right now for less than $1000.

It will bolt right up and there are several threads on the various forums on this tranny...

I like mine with the .73 overdrive...especially if you drive the highways a lot...

[josephmichael09]

Ok so this thread caught my eye and I'm hoping we get some good information here...

So I have this same transmission, and it is leaking a bit of oil. I am not sure if I should go through the trouble in replacing the seals or replacing the transmission. The transmission ratings that I have found give the transmissions "smoothness" is 3 stars out of 5.

Honestly, I think I want to go with an automatic. What is involved in swapping transmissions? What to look for when searching for a new transmission? What generally needs to be modified?

Also, my uncle purchases a lot of old trucks and cuts a lot of corners, so I am a bit skeptical of the advice he gives me, but he mentioned a 700 transmission. What is a 700 transmission?

[spookylynx]

700R4.... probably