| Crusing in the Passing Lane Joined: Jun 2011 Posts: 5,096 | Count gear teeth. If the cluster driven(front gear) is larger than the input shaft(mating) gear, it is probably not OD. OD trans without 2 speed rears are awkward because of large ratio gap where 3rd. was removed to make OD, but worthwhile otherwise. If it is OD would be fwd and right shift rail, direct would then be straight back. Either way, fwd and right shift rail will tell you. Steel pins in Al top housing are frequently loose, can relocate with epoxy or welding girdle on outside.
Ed
'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires.
'47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle.
'54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed.
'55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.
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