Oberstar Posted May 1, 2017 Report Share Posted May 1, 2017 My Father in Law has (2) Diamond T trucks- a 201 and 301. He's restoring them, but would like to change out the rear end for a bit more speed. Anyone know what the options are for gearing? Quote Link to comment Share on other sites More sharing options...
Plymouthy Adams Posted May 1, 2017 Report Share Posted May 1, 2017 there may be one or two folks here with Diamond T experience but would thinking the fishing here would be poor. The basics of rar end change as to why and how is covered pretty well and you can read the many thread by doing a search. The choice of rear axle will be dependent on the overall use of the truck as changes here will greatly affect your stock tranny gearing and the available torque at x rpm of the engine. However as a quick answer, you can pick a ratio based on paper racing from a multitude of online calculators and plug in the data and find a possible. Ratio now in mind you need to determine if you staying stock wheels. If so then the bolt pattern must remain the same or be willing to pay for axle flange alterations. Next also is wheel related, stock wheels and look will be the factor that gets you your axle width and should be measured flange to flange. Backing plate to backing plate is not a good number as many modern wheels are thicker brakes and thus will shorten any list in this area when in effect you are rally adding to but again..flange to flange. finding a modern with the right distance for the spring perches, odds are never, you will have to remove your old ones or purchase by proper size, (width and tube diameter). So to sum it up...wheels, width, ratio and grab a tape and head to the yards or find comparable axles on an internet chart and do a comparison to determine the most likely candidate prior. Quote Link to comment Share on other sites More sharing options...
lugnut123 Posted May 1, 2017 Report Share Posted May 1, 2017 A friend of mine put an Izuzu diesel in a short diamond T bus. I will see him this week end and see if he changed out the RR . That bus will git it down the highway. maybe a pic too. Quote Link to comment Share on other sites More sharing options...
Oberstar Posted May 1, 2017 Author Report Share Posted May 1, 2017 Lugnut, I would appreciate any help on that. Yeah, my FIL put a Cummins from a bread van into a 40 chevy. It's a looker, and gets great mileage. I'm just a fan of stock myself... Quote Link to comment Share on other sites More sharing options...
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