6_2LTZ

Have this issue too. Have yet to take it in.

Finally. I've been waiting for this. Never had it disabled since I may have opened the rear window once. I'll take a defrosting window over a sliding window any day.

My guess is shocks if nothing else changed. I run 40 to 45 psi in tires that are max 80psi. Two reasons for it coinciding with change in tires: The winter tires were a lower pressure and affected the way the truck hit the bumps. Or the road thawed out and the bumps changed. I changed out my ranchos for bilsteins and never worried about the rear end jumping around again.

I don't think the PPV Tahoe has a special drive shaft compared to a regular Tahoe or Silverado. It's just shorter overall and can handle higher speed. If you look at a 3500hd Crew Cab Long Box it has a 2 piece shaft thats 116" long. If you want to go faster you will need to change your drive shaft. Since it already has a 5" diameter shaft, a larger diameter shaft may not clear. I'd suggest checking with a driveshaft shop to see what they could do.

Unfortunately it seems like you have one of the longest possible driveshaft combinations with 2wd crew cab. Based on the critical speed calculations, it has a top speed of ~108mph. Which is the point where everyone fears their driveshaft will blow up. Here's a video of a two piece drive shaft: https://www.youtube.com/watch?v=4k8Qa474I1U

Every time this question comes around pandemonium erupts. I'm amazed that we got to the second page before being told to think about the children. For once I'd like a discussion on the real mechanics of why a speed limiter is in place. It took me way too long to find solid info one day so hopefully if I summarize what I found out maybe someone with actual knowledge can clarify it further. My understanding is the driveshaft is the weak point when it comes to top speed. The critical speed of the driveshaft occurs long before the truck tops out. (It's possible in trucks with a shorter drive shaft that air resistance could the critical factor in top speed.) A crew cab RWD truck is at a disadvantage due to having a longer drive shaft than the 4WD models. Here's a video of a straight cab standard box truck doing 120mph without issue. https://youtu.be/P32WCFcIzR4?t=141 Here's the driveshaft from that truck: https://www.dormanproducts.com/p-99708-946-306.aspx Specs: Diameter 3.5", Length 67.71", Material: Steel, Thickness: .083" Put those specs into this calculator here: http://www.wallaceracing.com/driveshaftspeed.php and you get ~5500rpm as the critical speed. A 6L80 ratio in fourth gear is 1.152, 3.08 rear end, I'll guess an 32" tire, and in the video the engine is turning at ~4500 rpm. Plug all that info here: https://www.dennysdriveshaft.com/potential_speed_calculator.html and we get a speed of 122mph. This confirm the tranmission gear. To calculate the driveshaft rpm take the engine rpm divided by the gear ratio. In this case 4500/1.152 = 3906 rpm. Under the calculated critical speed. To calculate the theoretical limit just multiple the critical RPM by the gear ratio to get engine rpm. In this 5500rpm is critical so multiplying it by the 4th gear will put us over the engine rpm limit. We'll use fifth gear instead. 5500*.852= 4686. Pop that in the calculator and we get 166mph with a 3.08 rear end. Based on researching the dorman site, it seems that there are many driveshaft combinations based on engine size, cab size, bed length, axle ratio, and drive type. The thickness can differ, material, and diameter for each model. Each truck will then have a slightly different critical speed based its' driveshaft.