| Crusing in the Passing Lane Joined: Jun 2011 Posts: 5,096 | I added a 'brownie' to my 1.5 ton GMC firetruck with 302 engine. 6.6 diff. ratio, made a very useful high gear. 5 speed direct trans.
Many 5 speed OD trans' are just converted direct trans' which they take 3rd. gear to make OD. That leaves a big gap without a 2 speed rear, so with a load, get stuck in too low gear because of big gap.
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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