Can i put a automatic transmission from 1985 Chevy pickup in 1970 Chevy pickup with manual transmission?

The 1985 pickup is a Chevy 3/4 ton pickup, and the the 1970 pickup is half ton. If i do put the automatic transmission in the 1970 would i have to also put the steering columns in from the 1985 pickup? Both pickups have small block 350s. and i also want to swap them out so will the holes to mount the engine line up?

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6 Responses to Can i put a automatic transmission from 1985 Chevy pickup in 1970 Chevy pickup with manual transmission?

  1. Jeremy S May 14, 2010 at 10:35 am #

    Yes you can. It will take a lot of work to rebuild the engine to work with the automatic transmission and rebuild the steering console to make it automatic.

  2. apoorapothecary May 14, 2010 at 10:35 am #

    The transmissions will physically bolt up. You don’t need to swap out steering columns; I don’t know if the 85 will fit yours; you may have to source one from a 70 automatic truck (or go aftermarket).

    Also, pay attention to vacuum connections (and tv cables, if you’re dealing with the TH400 or its variants.

    You may also have to likely swap out/move and possibly redrill the mount holes for the transmission crossmember, and possibly need to either change out tailhousings or change your driveshaft length. Physically measure both trannies to figure this one out.

    There’s a couple of other minor bits and pieces you’ll need to figure out on the fly as well.

  3. Truck May 14, 2010 at 10:35 am #

    the 15 years difference, I dont think so, U can find an adapter, and a ’70 has less power then ’85 and it may damage a trany, steering column probably has to be changed also plus the cooling lines and a radiator…
    its easier to rebuild the manual, then to switch, especially with a 15years difference…

  4. 69canam May 14, 2010 at 10:35 am #

    The swap should be no problem. My truck is a 1970 and it has a 1986 700R4 transmission. To make the swap a little easier, get a shifter that goes on the floor, then you don’t need to worry about the column. If you put in the column for the 85, you will have 2 ignition switches. You will have to make some adjustment to the transmission cross member. I don’t know if the cross member for the manual transmission can be used with the automatic. Make sure you either use the brackets from the 85 or buy new for the kick-down/TV cable for the tranny.

  5. Fuse May 14, 2010 at 10:35 am #

    I agree with canam … You should not have too many problems, its all in the little details.

    You dont say if they are 2wd or 4wd. When I swapped the 5 speed for an auto on my 93, I picked up a whole steering column for 75 bucks.

    You could easily put a floor shifter in since you have the hole in the floor already.

    Best of Luck!

  6. racer123 May 14, 2010 at 10:35 am #

    This is a very brazen swap. You will have to deal with the new tranny cross-member mount location and a new drive-line yoke to match.You most likely will have to re-size the drive line length,as well. The column shift range may be enough to accommodate the tranny,if the newer tranny is a 3-spd auto. Very important that the neutral lock-out remains very much effective- you don’t want your frankenstein to run someone over! Always adjust the shifter to be positively sure to hold the ‘park’ slot. Make sure that the E-brakes are allways engaged and effective- when parked. The ’85 tranny should utilize the same kick-down cable and vacuum modulator, but inter-year changes,at that time, may have the 3/4 tons running on the tvc cable ,of loan command. These must be attached to the ’85 intake and carb assembly to be accurately adjustible within defineable ranges.