I have a 01 that I'm putting in a ODLO switch tomorrow. Upon checking the location of the TCM I noticed Kennedy's instructions say there is one gray connector and one red connector. I think both mine might be gray. I haven't taken them apart yet but from the outside they both look gray. If so which one is c1 and which one is c2. Should I assume the one on top is one and the bottom is two? I won't start the install until I am sure about the number of each connector. Or will I readily know the answer when I take the connectors apart? Any help is appreciated. I have an appointment for the recalibration on Monday.............Bob

The instructions were also in a GM TSB (not sure what the number was). I do have to ODLO switch on my 2001 but it is almost useless.

I want to stay in 5th, not 4th towing our high profile 12,000 lb. 5er. The recalibrations did improve shifting a lot (less hunting) and as long as I am going at least 65 mph, it stays in 5th pretty well.

In 4th, you will be lucky to get 10 mpg. Only really useful if you were towing a house !

I just got the truck and am planning a trip next week. I haven't pulled my fith wheel yet but thought having the ODLO would make descending the mountain passes much easier. Is this not true?

I haven't pulled my fith wheel yet but thought having the ODLO would make descending the mountain passes much easier. Is this not true?If you have tow/haul mode engaged, you can activate the grade-braking feature by just tapping your brakes. The Allison will downshift as necessary to keep your speeds in check.

I put my switch in 3 years ago.

Best thing I have done to the truck for towing. To bad GM didn't think of it.

Taking it out of OD is only for HILLS, not for normal flat country driving. Grade braking in the ally works just fine in 4th.

It is a tool to optimize rpm and speed while negotiating hills. It keeps the ally from shifting in and out of gear.

I would not tow without it. And I am towing 13K 5th wheel trailer.

I have a 01 that I'm putting in a ODLO switch tomorrow. Upon checking the location of the TCM I noticed Kennedy's instructions say there is one gray connector and one red connector. I think both mine might be gray. I haven't taken them apart yet but from the outside they both look gray. If so which one is c1 and which one is c2. Should I assume the one on top is one and the bottom is two? I won't start the install until I am sure about the number of each connector. Or will I readily know the answer when I take the connectors apart? Any help is appreciated. I have an appointment for the recalibration on Monday.............BobWhen you disconnect them. You will see the different colors.

I installed the switch and the LED. My questions now are, Is the LED supposed to operate before the programming is done? Are there any operating characteristics I should look for before the programming is done?
Thanks..........Bob

They need to reflash the TCM.

Your reasoning is that the tranny is "hunting/seeking/shifting to much".

That should be a freebie.

Switch and LED won't work without the reflash, if my reading is correct.

Good luck

Thanks for the replies. Now I can't wait to have the computer programed on Monday................Bob

The TCM is now reprogramed. The ODLO works as described. I am looking forward to towing my 12k 5th wheel to Palm Springs from Reno tomorrow and learning how the Allison works going down hill in T/H. I am sure I will have more questions when I get back next week...........Thanks