Swap Mack T318LR tranny for Eaton 18 tranny

[Vac-Daddy]

I was hoping on getting some insight on doing a swap, Mack 18 to Eaton 18. My Mack tranny needs to be replaced and parts are hard to get and very expensive. I can purchase a very good Eaton 18 For quite cheap from a good buddy of mine. What's everybody's thoughts, please help? 2007 Mack Granite.

[Geoff Weeks]

boy, did we get "off in the weeds" on this thread.

[Joey Mack]

sure did..   But,,,, thats what we do here..  I did ask some off track questions that you guys were willing to answer...

[Joseph Cummings]

1 minute ago, Geoff Weeks said:

I just put my numbers into Spicer's driveshaft calculator and it spits out what I need to know. Critical and 1/2 true critical.

When I was in school we didn't have "driveshaft calculators". We had to do the math with a pencil and paper and a slide rule. I had to walk there in torrential rain wearing a yellow rubber rainsuit and galoshes. Uphill both ways

[Geoff Weeks]

Yeah, well he had to do it in snow!

[Joseph Cummings]

Starting at the lower right and ending with the upper left (I know its kinda Chinese or something) is how a power transmission shaft tries to distort as you hit each critical speed.

Think of an out of balance tire. You hit a speed and it's bouncing, speed up and it smoothes out, then you hit another bouncy speed and so on

 

[67RModel]

The Mack transmission might seem more expensive than the Eaton on the surface but I can almost guarantee it would be cheaper, all things considered, to just replace what you have. Either by overhaul or just getting a reman unit. Call Weller or similar order exactly what you have delivered to whatever shop you use. Once it gets in they can have it swapped out and everything switched over in a day and you can be back to work the next. Then send your old one back as a core. I would forget about the Eaton in your case.