Overdrive options

[cs641]

I have an old MH on the M500(?) Chassis with the 440 and TF727. I'd like an overdrive but I'm not crazy about the $3000 price tag thru gear vendors. Could the A518 be made strong enough for a 13,000LB MH and trailer or is there a better trans to use?

[Rickf1985]

They used it in the one ton pick ups so it should have no problems. As long as it is set up with a proper shift kit and a good oil cooler.

[cs641]

Thanks. I doubt I'll see any sort of MPG increase but in theory I should pick up several MPH, right?

Would like to get my sweet spot up from 60 to maybe 65/66

[Rickf1985]

The 518 came in a lockup and a non lock up version. If you have the lock up version you might gain some speed and mileage, if you have the non-lockup you will most likely just gain a lot of transmission heat from torque convertor loss due to pushing a barn door through the air at 65 MPH. What did the trans you have come out of? I am thinking along the lines of a 47RH out of a pick up. Be sure it has the gas converter and not the diesel. What rear end ratio do you have in the vehicle now?

Here is a engine RPM/Speed calculator for you to play with. You want to keep your engine above at least 2100-2500 RPM minimum at 65.

http://www.crawlpedia.com/rpm_gear_calculator.htm