I have a 2002 Chevy Duramax 2500 LB7 6sp, I bought the truck about a month and so change ago. On the way back from buying the truck we put it in cruise control and it was running and driving fine for about 30 to 45 minutes then the check engine light came on and the truck wasn't like shaking but it was going back and forth real hard almost like the back wheels were locking up for a split second an letting go at 65 mph then i would hit the brake and take it out of cruise control and it would stop then i put it back in cruise it would be fine for a minute or two then start going back and fourth hard. So I just quit using cruise and it was fine. fast foreword and i tried putting it in cruise and it didn't work light didn't come on or anything. still doesn't work.
Then like a week or two later i was driving on the high way and the check engine came on again but this time i was only in like third gear and i would get to about 2000 rpm and wouldn't go any higher or any faster and i had to shift into forth and it would do the same thing then i got up to 65 mph and it starting going back and forth hard again, and this time i wasn't in cruise control and again it was doing it at 65 mph, i would take my foot of the gas and it would stop then i would get it back to to 65 mph and it would start doing it again and wouldn't go over 65 mph, so this time i made the truck tough it out an just let it go back and forth really hard and it stopped after about a minute of me doing that then it would get to 65 mph and it was like i had no power to go pasted 65 mph. So i took it to a shop to service and look over the truck. Well i had been noticing that i was always low on coolant and they looked at that and my water pump was out so i go that fixed then i got a call and they said i had a hole and my trans case, from what I've read basically all 01 to 04 duramaxs have had this problem. they said it drive just fine when they drove it, it didn't shake or nothing or the check engine light come on. I drive it for a couple days and it was fine then it started doing it again at 65 mph not in cruise
So really i just want to know whats going on with it. It really only dose it at 65 mph it has done it at 70 a couple times but that it. I'm thinking it is maybe the back axle or i know in the automatic trans and engine then those years will go into pimp mode i was wondering if the manual trans and engine can go into pimp mode. an just to throw in it docent happen every time i drive and some time the truck will only go up to the speeds 70 to 75 mph and not go any fast like it was hitting a governor but sometime i can get it to 85 to 90 mph easy and it acts like the governor is coming on.
Then like a week or two later i was driving on the high way and the check engine came on again but this time i was only in like third gear and i would get to about 2000 rpm and wouldn't go any higher or any faster and i had to shift into forth and it would do the same thing then i got up to 65 mph and it starting going back and forth hard again, and this time i wasn't in cruise control and again it was doing it at 65 mph, i would take my foot of the gas and it would stop then i would get it back to to 65 mph and it would start doing it again and wouldn't go over 65 mph, so this time i made the truck tough it out an just let it go back and forth really hard and it stopped after about a minute of me doing that then it would get to 65 mph and it was like i had no power to go pasted 65 mph. So i took it to a shop to service and look over the truck. Well i had been noticing that i was always low on coolant and they looked at that and my water pump was out so i go that fixed then i got a call and they said i had a hole and my trans case, from what I've read basically all 01 to 04 duramaxs have had this problem. they said it drive just fine when they drove it, it didn't shake or nothing or the check engine light come on. I drive it for a couple days and it was fine then it started doing it again at 65 mph not in cruise
So really i just want to know whats going on with it. It really only dose it at 65 mph it has done it at 70 a couple times but that it. I'm thinking it is maybe the back axle or i know in the automatic trans and engine then those years will go into pimp mode i was wondering if the manual trans and engine can go into pimp mode. an just to throw in it docent happen every time i drive and some time the truck will only go up to the speeds 70 to 75 mph and not go any fast like it was hitting a governor but sometime i can get it to 85 to 90 mph easy and it acts like the governor is coming on.
