So it's time to rebuild the 700r4 in my car. Also have a friend that has one I can buy and rebuild while mine is in the car. The one in the car is out of a 91 and I know it has all the upgrades/better parts. Is there a way to know the year or if it's a better 700. I know the input shaft got upgraded did all the upgrades a me with that? Any advice is appreciated.

 

Look for the stamped numbers on the case. This is what the stampings meant back in 1987.

It should look like: 7YWM-Y-00597618-329 B

7 = Year (1987)
YW = Model
M = 700R4
Y = Plant (in this case Toledo)
00597618 = Serial Number
329 = Production Date (Julian Calendar)
B = Assembly Shift (A/B = 1st shift; C/H = 2nd Shift)

Most all of the factory improvements were made by Jan. 1987.

In your case, you can determine the year of manufacture but you'll probably not be able to tell which one is better over the other. Many of these transmissions have already been rebuilt and in all likelihood been upgraded in some fashion.

I would look for the one that has the latest assembly date.

 

Thanks that's good to know. Plan is to rebuild one so I can do a quick drop and swap of mine. Then rebuild it and have it for a back up.