Trans/Diff not Engaging

Every now and then (every few weeks), I will accelerate from a stop and it feels like either the transmission or rear end does not engage correctly. The motor revs up, but not a like it does in neutral, it revs like there is a load on it. The truck will move forward slowly but feels like something did not catch/engage properly. I will then take my foot off the accelerator (for fear of breaking something) and accelerate again. Then everything feels okay and the truck drives and shifts fine. I changed both trans fluid & filter and differential fluid about 10,000 miles ago. Any thoughts?

2002 1500 4.8L Silverado 2x4
145,000 miles

Rear drum or disk bakes? If rear drums you may want to look there.

They are rear disks. Thanks for the reply.
BlackBerry8310/4.5.0.110 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/102

There is a TSB out on this. There is a bug in the programming for the trans and every now and then it will start off in second gear. My Silverado used to do it now and then as well but because it was a 2000 there was no update for the programming specifically for that. Talk to the service department at your dealership and tell them what it is doing and if they know what they are doing, they should know about the program updates to solve this problem.

Hmmm, that's interesting. Now that you mention it, it does feel like the trans starts out in 2nd. Kind of wierd that it would just now start to do that. I've owned the truck for 6 years and put 100K miles on it. I'll call the dealer and let you know what they say.
BlackBerry8310/4.5.0.110 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/102

I just talked to the service manager at the dealer, he was aware of the issue and the tsb to correct it. Now I just have to fork over $100 (this includes updating all of the programming) to fix it. Thanks for the good info Kenny!
BlackBerry8310/4.5.0.110 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/102

I just talked to the service manager at the dealer, he was aware of the issue and the tsb to correct it. Now I just have to fork over $100 (this includes updating all of the programming) to fix it. Thanks for the good info Kenny!
BlackBerry8310/4.5.0.110 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/102

if it is starting in second it could be a bad solenoid 1st gear. I actually seen this on a tahoe ...starting in second gear but not always..turned out the solenoid coil had a poor soldering joint [made in mexico]........

getting the drive train codes first should show this ..I would not have any parts replaced or work done until the drive train is scanned...

how could the programming get corrupted ?

Good point, I'll have it scanned before I have the programming updated.
BlackBerry8310/4.5.0.110 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/102

I paid $75 plus tax for a "general driveability issues" programming update for my 2000 Silverado and that solved my same problem although the service manager at the dealership i had it done at said that the update may or may not help, but it was worth a shot.

Did it work, and did your trans develop this over time or did it happen from day one? Like previously mentioned, it seems unlikely that the programming could become corrupted.
BlackBerry8310/4.5.0.110 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/102

I bought the truck used at 3 years old so I can not say if it did this from new or not, and like you, one day taking off from a stop it did this. Same as you, I got off the throttle right away for fear of breaking something but everything was fine when I put my foot back on the gas. At that time I had had the truck maybe a year or so. It did not do it again for quite a few months but it did it again twice within a week and that is when I called the service department of a nearby dealership where I was informed about this being a known programming "bug" and that there was an update for 2003 and newer, but for my 2000 there was only this general driveability issues programming update. I wouldn't go as far as saying the programming was corrupt because it was working, just not right all of the time (buggy) just like windows, hence all of the updates to correct "issues" which may or may not happen. I got rid of the truck about 5 years later with 187,000 kms on it and it had not done it again.