Herm sells complete 25-percent overdrives or his signature 30-percent overdrive unit, in addition to offering rebuild services ... an overdrive behind a Cummins 4BT pushing over 800 lb-ft of ...

If you're searching for information about the Cummins 4BT diesel engine and how it differs from the 6BT, you likely fall into one of three camps. Camp one enjoys reading about obscure diesel engines.

Our farmer snatches off two of the stock Cummins valve covers and replaces them with one of the dual valve covers from the tractor’s 4BT ... better managed until a rebuild can be performed.