Why Fast Coolers?
A manual transmissions like the NV4500 hold a mere 8.5 pints. In 4th gear, the transmission stays cool, but in 5th gear (overdrive) it can quickly heat up. There is just not enough gear oil capacity. It didn't matter what oil I used, it wasn't enough. So I did the math and compared it to the gear oil capacity of semi-tractor trailers in retrospect to their gross cargo weight and compared it to my pickup trucks gear oil capacity and its gross cargo weight. What I calculated was, my pickup should hold at least 7-8 quarts, not 8.5 pints. Two more quarts would make a huge difference, and it did!
The best way to add 2 quarts is to extend the pto covers with aluminum (for cooling) to add gear oil capacity.
I quickly found out that with Fast Coolers on my NV4500, I could keep the temperatures under 200 degrees versus the previous 230 degrees.
And one side does for all. Fast Coolers would have fit a 4 speed from 1932 and they will fit our brand new truck today. The SAE 6 bolt PTO access cover has been the same bolt pattern for over 80 years in all trucks. Dodge, Ford and GM all utilize the same SAE 6 bolt PTO access cover. They will fit, and they're cool!
-Verlyn Fast (Owner)