SM420 overdrive?`

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Jan 15, 2003
Is there an overdrive made for the SM420?
Ok, I just did a search for the overdrive and found info on the Ranger Overdrive. What kind of gear ratios could I expect with stock 4:11s, SM420 and 3speed tcase?
Are the Ranger ODs any good? If they split gears, wouldn't it be just as effective as the ToyBox or Atlas II?
Rangers are nice....not sure on availability tho...

The Atlas and Marlin stuff will not give you overdrive, as their high is 1:1 just like a stock t-case or tranny, but will give you much lower crawl speeds for offroad.

IMO, run taller tires and call it an overdrive (ie: 33x10.5 or something)
I'm runnin' 33, 12.50 thornbirds for now...35 BFGs or MTRs in the hopefully near future. :D
I run a Ranger in my rig. The overdrive is 27%. I run 31 x 10.50 tires and turn 2200 RPM at 60 MPH. No trouble yet with noise, failure, vibration, or otherwise (I'm about 380 HP at the flywheel). The install was easy but only because I had the body off and was doing my SBC conversion at the same time. Keep in mind it moves the engine 7.5 inches up if you don't move the drivetrain. Doing so means you can't run a long water pump, however, having my clutch fan right up on the radiator is very nice ... no trouble with heat. Happy to help with any other questions you might have.

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