I'm going to be pulling a 5000# bumper pull single car trailer for a good 5000 miles starting Nov 15. My RPMs at 75MPH in OD are 2200. Is this going to be okay? I would assume it'll be fine on flats and medium grades but even if the MOTOR can haul it, is there some point where I should switch into OD OFF for the sake of not killing the trans or keeping EGT's down???

My concern is that with OD off, I can't go more than about 70MPH and that is at almost 3000 RPM.

On another note, I just added the 48RE to my RPM chart PHP script. You can put in your tranny, rear end gear ratio and tire height and it'll tell you speed @ RPM.

http://xj.cdevco.net/rpmchart.php

If there is any need I can add the NV5600 and any other tranny.

PS
I heard that if I have a 48RE behind a SO I might have a big old 11.5" ring gear. Any marking on the diff to confirm this?

 

You don't need to worry about downshifting out of O.D. until you get down to 1500 or 1600 rpms. If you are only towing 5000#, your CTD will hardly know it's there. As for the 11.5" ring gear, I'm afraid I can't help.

DeWain

 

Towing with mine and I come to a hill and don't take it out of OD and the RPMs drop it will shift its self.