Thanks for all of the advice! I will work on getting some things switched around and hopefully get the temps down. Thanks much!

 

That BD cooler doesn't seem very large. Might be pretty heavy at 4" thick though... If you can find a good 6.0 cooler and mount it up front, that will be ideal. The Tru-Cool MAX cooler looks like it has a lot of surface area as well, so that is another good option...

If it were me, I would try moving the BD cooler out front so it can get cooler air and reduce the length of your cooler lines. You might find that it works much better in that position and then you wouldn't need to purchase anything different. I have a Tru-Cool brand supplemental cooler and it's not very big. (10" x 10") but it does the job pretty well. (The Tru-Cool MAX wasn't available when I ordered my cooler...) Assuming your fan clutch is working correctly, you will find that it pulls quite a bit of air. In your case, since you have to drive slowly, it would be a good idea to wire up a manual override so you can turn on the BD fan a bit sooner.

The TC lock idea is interesting as well. I have a manual TC lock switch in my cab but I've never used it while ascending steep grades. No particular reason...I just never thought about trying it to see how effective it might be in keeping things cool. So, I only use it in conjunction with the EBPV to help control my speed while descending. I presume you have to tow back down the same logging road... how do you control your speed? Do you just leave it in 1st gear and use the service brakes when necessary?

 

My advice is simple: Follow Mark's advice.
I did just that. Grabbed a 6.0 cooler from a junkyard for $50 and my flaming POS tranny problems are solved (fingers crossed, knocking on wood, yada yada).