Technical 1955 - 1957 Chevy Pickup Wiper Motor Differences?

Are there any significant differences between 1955, 1956, and 1957 Chevy truck electric wiper motors? I had always thought that they were the same. However, the Hollander interchange shows that they do not interchange. My 1960 Chevrolet parts book list two different part numbers. One for 55 & 56 motors, and another for 57 motors.

Are there really any major differences? If so, what are they? Do they mount differently? Use a different switch, or wiper linkage? Is it very difficult to mount a 55, 56 motor in a 57 pickup?

I'm working on a 59 GMC, which uses the same motor as a 57 Chevy pickup. I already have a 59 Chevy pickup electric wiper motor, (same as 58 Chevy passenger car), but there are a few problems getting it mounted and the linkage hooked up.

 

...where's squirrel?,...bet he knows

 

It's been awhile, but the difference in in the plastic slide that the actuating cable goes to. I believe they will all work or interchange. Cosmetically some had square corners and others one round corner. It was pretty much the same for the passenger 55-57 and Corvette. But I'm not positive, like I said it's been awhile.

Pat

 

58-59 wiper motor travels in a full circle uses arms 381 on rt and 382 on lt.55-57 motor travels back and forth uses arms 346 and 347. they mount a little different

 

It was also mentioned on another recent thread there is a bump/relief on the 58/59 panel underneath the cowl panel that interferes with the 55.5/56/57 wiper motor mounting and operation.

 

I put a 56 motor in my 57 and it seems to be fine. Not sure what year the control knob assembly is, though.

 

Thanks everyone for the replies. It sounds like the 55, 56, and the 57 Chevy truck motors all interchange and 55 - 59 GMC's use the same motor as 55 - 57 Chevy trucks. That's the important thing to know.

The 58 - 59 Chevy trucks use different motors, which are the same as a 58 Chevy passenger car. This explains why the 59 Chevy pickup motor, that I already have will not bolt into my 59 GMC.

As far as the 55 - 56, and 57 motors, the main difference is in the switch. As shown in the following photos.


1955 - 1956 motor,



1957 motor.

Hopefully, I've got all of this straight.

 

I know this is an older thread, and I didn't see this answer so I thought I would add this for completeness.
I have a 55 Cameo, and I installed an electric wiper motor from a 57 car. The electric wiper motor is activated by the same cable that actuates the vacuum wiper.