Plain and simple, Do all "Z71" trucks necessarily havethe 5.3L engine? I understand Z71 is an Off Road package, and by the same token, do the trucks with "4X4" on the rear quarters always mean it has the 4.8L engine? I'm thinking NO, but never knew for sure. I'm talking without special order trucks only. I know my wifes Avalanche has the "4X4" on hers, and her Av has the 5.3L in it. Thanx, Jim

 

Nope. It's all random.

 

It's all in the truck. What I mean is like Charger said, it's all random. However you can get the same Z-71 package in both motors. Now you can get the Z-71 package in a 2x4, also in the 2500HD's. So nowall of uswill really have to look at the truck to see what it has in it! Chevy has basically offered all trucks in all packages. More choices for the customer. I am not complaining!

 

This is a general idea of how it works, I am not 100% correct on years here and details so don't bite my head off.

Eighty something to early nineties I believe, was the Z71 option on a single cab truck meant a 5.7 V8 instead of the standard equipment 5.0 and also included the badging, heavier duty shocks and a limited slip rearend. BUT Ext. cab 4X4 trucks and long bed 4X4 typically came with the 5.7 anyway.

Around the Mid Nineties when the Vortec was popular, the engine upgrade was just about gone. Now all you got for your money on the Z71 was the shocks (maybe the jounce bumpers, I can’t remember), the badging and the limited slip rearend. The 5.7 wasn’t standard issue, but still available and more common in the Z71 then any other light duty trucks.

Late Nineties, the 5.7 is typically special order, available on HD trucks, or optional on the Z71. They squeezed more HP out of the 5.0 making it standard issue on light duties all-together. Still got the heavier jounce bumpers, badging, shocks and limited slip rearend.

99 New body style and up. You pretty much get jounce bumpers (I think shocks) and the limited slip rearend only. Engine is standard duty based on vehicle weight only. Example: An Ext. Cab 4X4 has a 5.3 no matter if it is Z71 or not.

06 (I believe) and up you get the badges, the jounce bumpers, NO MORE SHOCKS, and the limited slip rearend.

I know off hand that mid to late nineties Z71 suffered from rearends that went bad around 100,000 miles due to some “pin� that holds the gears in place. It wears out and wiggles out letting the gears move freely.

 

easiest way to do it? check the vin.

 

Don't tell me crap like that. Now I'm worried.[&:]

 

Ha that actually could be true on what happend to my rear end originally at 148k miles, the spider gears over rid themselves cause the middle locking pin became more loose over time. Though one tire fire burn outs accelerate this process much more... :P

 

well there is also a 6.0 liter option on some of the later model 271 1500 but its the weird 1500hd model. the z71 is "off road" package which all it really means is like stated above you get a little heavier duty shocks and bumpers and you also get the trans sid plate and engine skid plate.