Just purchased a 2003 C4500 LB7 Duramax 300hp Allison 1000 tranny.

According to the spec sheet for the truck, the speed limiter of 75 mph is a $24.00 part. If they can add it why am I finding it so hard to get a straight answer on how to remove it?

This is a vehicle used for personal use (not a business) it's a private hauler.

GM say's it can't be done (I think it's a liability issue on their part).

I have already purchased one programer (that claimed to be able to remove it)...needless to say it is being shipped back this week.

I am also going to post this thread in the Med-Duty truck area.

Please help!

Don't know much about the 4500's but the 25 and 3500's have a speed limiter of 96mph and some of the program's available will remove it or raise it anyway, don't know why your's would be any diffrent but I guess it is.

Good Luck

DD

Usually the speed rating of your tires seems to determine your speed limiter setting.
Our stock LT245/75/16 tires have a "Q" speed rating of 99 MPH.

Don't the 4500 and 5500 trucks come with the medium duty 19.5" tire?
The couple of 19.5 speed ratings I've come across in the past all seem to have a 75 MPH speed rating.
You just might want to leave things alone.

1 diode will make it do 100+