What is the difference in the steering gear assemblies for 3 speed column and 4 speed floor shift? What about the differences between 1956 and 1957?
Thanks for any info.
"Do not walk behind me, for I may not lead. Do not walk ahead of me, for I may not follow. Do not walk beside me either. Just leave me alone, you're starting to freak me out."
jmoore - I'm no expert when it comes to GMC Master Parts Books, but a search through GMPartswiki for GMC Steering Gears, shows the below details from a 1963 Parts Book covering the years 1955 (Y), 1956 (X) and 1957 (T) for your Model 150 (15 as shown in the book).
There does appear to be a specific "w/4 Speed Trans" gear box for a 150 for 1956 (X) and 1955 (Y) - GM# 5668106. Then there is another 4 speed specific gear box for 1957 (T) - GM# 5671458. Also listed is steering gear for the 1956 (X) and 1957 (T) trucks with power steering - GM# 5684268. Separate from those 4 speed specified gear boxes, there are 3 different part numbers for "STD CAB" (Standard Cab?). One for each of the model years 1955, 1956 and 1957. My best guess is those represent the standard 3 speed trucks, but again that is only a guess on my part.
Perhaps some of our GMC guru's can shed more light on your question???
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What is the difference in the steering gear assemblies for 3 speed column and 4 speed floor shift? What about the differences between 1956 and 1957?
I noticed that you have a '57 GMC 3/4 ton (150), so my info is from a 55.2-60 GMC Master Parts Book and will deal strictly with '56 and '57 100, 150 and 250 series trucks. You didn't mention power steering, so I'll leave that out of the mix as well.
The case is the same and as far as I can tell so is everything inside the case.
The steering column jacket (outer tube) varies based on transmission type, 3 speed, 4 speed or Hydra-Matic. These differences are mostly (maybe all) due to holes for mounting shift linkages. The jacket and inner shaft varies in length from '56 to '57 because the '57 has a dished steering wheel and a shorter steering column. If you mount a '57 steering wheel on a '56 shaft you will find that it is about 3" closer to the driver than when mounted on a '57 shaft. The opposite is true of a '56 steering wheel on a '57 shaft.
If you have factory turn signals, the '56 turn signal stalk comes out at a 90 degree angle to the steering column while the '57 mimics the "dish angle" of the '57 steering wheel.
Last edited by Bill Hanlon; 01/18/20259:18 PM.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12 '52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
What Bill said about the column jacket and shift linkage mounting holes holds true for the AD series trucks as well. Internally, the steering gears are identical whether a three on the tree or a floor shifted 4 speed. GM, like most other manufacturers try to standardize things to save costs.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
So outer sleeve mounting holes is only difference on 3 and 4 speed transmissions 56 to 57 difference is length due to steering wheel differences.
Seems to be the same for GMC and Chevy
Thank you gentlemen.
"Do not walk behind me, for I may not lead. Do not walk ahead of me, for I may not follow. Do not walk beside me either. Just leave me alone, you're starting to freak me out."
