Originally Posted by Blake Clark

When you have it in "D" and you hit the +/- it should throw the gear indicator to the right and show which gear you are currently in. You must hit the "-" button to activate the selectable gear switching. When starting off you can put it on gear "1" and upshift using the + for each gear change. You can also do the same thing downshifting to give the engine a higher RPM range to make the exhaust brake more effective.

Another way to use it is for setting the highest gear that the tranny will shift into. For example, when towing a heavy load and not wanting the tranny to shift higher than fourth gear, place the numerical indicator on "4" and the tranny will not shift above 4th gear, normal upshift and downshift up to 4th gear will remain the same.

If you are driving along using the auto/shift function and want to revert back to the standard D mode, just mash the "+" button until "D" comes up. If you are driving along in "D" and want to use the auto shift mash the "-" button and the gear indicator will come up.

The +/- selector has nothing to do with exhaust brake control other than allowing you to keep your truck in a lower gear effectively raising the rpm's and in turn the effectiveness of the exhaust brake.


The 68RE has three basic modes of operation, regardless of exhaust brake function.

1. Standard operation "D", tranny operates normally.
2. Tow/Haul Mode, tranny uses a set point vs engine load and rpm to maximize effectiveness when towing. It will not shift into overdrive until its needed. Downshifts will be roughter to gain engine rpms to help the exhaust brake function when needed.
3. Auto/select, this lets you choose when and how the tranny shifts.

Originally Posted by AttilaTheHun

Thanks BlakeClark for your explanation of how the +/- option works. Tried it today and it worked great. The problem was that I wasn't holding the button down long enough to get it over. Thanks again for the response and the explanation. Really appreciate it.