steelman Posted January 13, 2015 Share Posted January 13, 2015 I have a couple of questions someone may know the answer to. Can I put an automatic transmission in an older R model Mack with a 237 or a 300 (with a single rear axle)? Also, is it possible to put adapters on the hubs so I could put smaller wheels and tires on so it would be lower to the ground? (Say 19.5 tires) Thanks, Steelman Quote Link to comment https://www.bigmacktrucks.com/topic/38432-mack-modifications/ Share on other sites More sharing options...
Superdog Posted January 13, 2015 Share Posted January 13, 2015 not sure about hub adapters but a automatic wouldn't be a problem. A friend of mine put one behind a E6-350 in his Superliner Quote Link to comment https://www.bigmacktrucks.com/topic/38432-mack-modifications/#findComment-274204 Share on other sites More sharing options...
Superdog Posted January 13, 2015 Share Posted January 13, 2015 why not just go with a really lo pro 22.5 like they use on dropdecks? 1 Quote Link to comment https://www.bigmacktrucks.com/topic/38432-mack-modifications/#findComment-274206 Share on other sites More sharing options...
steelman Posted January 14, 2015 Author Share Posted January 14, 2015 Thank you for the reply. I am not familiar with the lo pro 22.5 tires. I am thinking of using an R model (or U model) to pull my 36' PJ gooseneck hydraulic dove tail trailer to take my "toys" to the shows. I was interested in using a vehicle that qualified as an antique, and since I am getting older, I wanted something that rode a little lower to the ground. Won't put that many miles on it, but figured it would last forever in that kind of situation. Several friends use 1 ton pickups, but I wanted a little more meat around me. Any thoughts, or am I barking up the wrong tree? Quote Link to comment https://www.bigmacktrucks.com/topic/38432-mack-modifications/#findComment-274214 Share on other sites More sharing options...
thomastractorsvc Posted January 14, 2015 Share Posted January 14, 2015 It would be really slow with smaller tires not that it would be super fast with large tires 1 Quote Robert"I reject your reality and substitute my own." Link to comment https://www.bigmacktrucks.com/topic/38432-mack-modifications/#findComment-274215 Share on other sites More sharing options...
Superdog Posted January 14, 2015 Share Posted January 14, 2015 you would just have to find a ratio that would provide that right road speed with the smaller tires. I'll look for sure,but I think the tire size is 255/70R22.5 There is quite a bit of height difference between those and a 11R22.5,I think they would work and would sure be alot cheaper than getting adapters and all new wheels Quote Link to comment https://www.bigmacktrucks.com/topic/38432-mack-modifications/#findComment-274217 Share on other sites More sharing options...
41chevy Posted January 14, 2015 Share Posted January 14, 2015 you would just have to find a ratio that would provide that right road speed with the smaller tires. I'll look for sure,but I think the tire size is 255/70R22.5 There is quite a bit of height difference between those and a 11R22.5,I think they would work and would sure be alot cheaper than getting adapters and all new wheelsIf it a single axle why not go to a 2 speed rear to give a "highway gear" with the automatic, it would also compensate for the smaller diameter rubber. Paul Quote "OPERTUNITY IS MISSED BY MOST PEOPLE BECAUSE IT IS DRESSED IN OVERALLS AND LOOKS LIKE WORK" Thomas Edison “Life’s journey is not to arrive at the grave safely, in a well preserved body, but rather to skid in sideways, totally worn out, shouting ‘Holy shit, what a ride!’” P.T.CHESHIRE Link to comment https://www.bigmacktrucks.com/topic/38432-mack-modifications/#findComment-274220 Share on other sites More sharing options...
TeamsterGrrrl Posted January 14, 2015 Share Posted January 14, 2015 There are no adapters that will allow you to put 19.5 wheels on in place of 22.5, the brake drums are too big to fit 19.5 rims over. As far as the automatics, most of the R models you see with a 237 or 300 have overdrive top gears. To avoid losing a lot of speed capability, you'll need a newer overdrive Allison automatic with the overdrive top gears. An Allison with the torque capacity to handle a 237 or 300 Maxidyne can be pretty spend, even if it's 15 years old. Quote Link to comment https://www.bigmacktrucks.com/topic/38432-mack-modifications/#findComment-274246 Share on other sites More sharing options...
Ezrider Posted January 14, 2015 Share Posted January 14, 2015 the tire on my pusher axle is a lower than standard low pro 22.5 i want to say its a 255/70 if memory serves the drive tires in that picture my truck had standard low pro 24.5 on the drives for size reference. Quote Link to comment https://www.bigmacktrucks.com/topic/38432-mack-modifications/#findComment-274250 Share on other sites More sharing options...
Ezrider Posted January 14, 2015 Share Posted January 14, 2015 the tire on my pusher axle is a lower than standard low pro 22.5 i want to say its a 255/70 if memory serves the drive tires in that picture my truck had standard low pro 24.5 on the drives for size reference. Quote Link to comment https://www.bigmacktrucks.com/topic/38432-mack-modifications/#findComment-274251 Share on other sites More sharing options...
mack mhe9 Posted January 15, 2015 Share Posted January 15, 2015 And a 255/50 will cost more then the 19.5 but will also last a lot longer. Easyer to get om the road. Quote Link to comment https://www.bigmacktrucks.com/topic/38432-mack-modifications/#findComment-274424 Share on other sites More sharing options...
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