whats the rear gear on a 05 z71 tahoe. I had an idea to change out the gear for a higher one or the torque converter. what do you guys think?

Probably came with a 3.23 gear ratio. Just curious as to why you want to go higher. Do you do a lot of highway driving? Because your city mpg and acceleration will both suffer.

I like the get up and go, passing gear. my work 09 tahoe runs very good takes off like a champ and keeps going, my 05 dosent.

Well you want a lower gear then. Not a higher gear. What size tires are you running? If you have stock tires and would like to lower your gear ratio I would recommend a 4.10 ratio, a 3.73 won't be a real dramatic noticeable difference. A higher stall tc would also do the trick. I'd search it but I believe many members have installed the stock trailblazer 3000 stall converters. But if you do a lot of towing I'd recommend regearing.

I was just advised that i would have to change front and rear gears, so i might change the torque converter. how dose it affect towing?

I called TCI torque conveters & the one I liked is theTCI Breakaway It provides approximately 2400 to 2600 rpm flash stall with out negatively affecting part throttle driving, now i need 2 find out if i got a 4L80E or 4L80E, 11" or 12" converter. The price dependes on the model. (05 Z71 Tahoe)

You have a 4L60E trans. Just make sure you do your homework before doing either mod. There is plenty to search here on Z71TS. Good luck.

Check your glove box for your gear ratio code.

Later GMT800 2WD were typically 3.42, but sometimes 3.23 and sometimes 3.73
Later GMT800 4WD were typically 3.73, but sometimes 3.42 and sometimes 4.10

As far as torque converters, absolutely do it for a noticeable difference in performance (even untuned), but note that TCI is no longer a reliable brand for torque converters. The Big 3 brands right now are Circle D, Precision Industries (Vigilante), and Yank, but a quick look around PerformanceTrucks.net will steer you toward Circle D.

I'm running Circle D's upgraded 278mm (11") I6 Trailblazer converter with a 3K-3.2K stall and love how much more passing power I have, but I got a larger one because the cam I am going to install shifts the power band up higher than the stock cam. If you want to tow frequently and keep your stock cam, they make a modified I6 Trailblazer converter that has a 2.6K-2.8K stall. Either one of these is $375 shipped for members of the PerformanceTrucks.net forum.

If you want something even milder, but still better than stock (i.e., in between the Trailblazer stall and the stock stall), Circle D also sells an upgraded 300mm (12") 4.8L converter (which has a higher stall than the stock 5.3L converter), with available two different stall ranges of 2.2K-2.4K and 2.4K-2.6K.

Thanks for filling in the details!

I contacted Circle D and got SKU# 01-07-07-1A GM 278mm HP 4L60E LS Torque Converter-HP 2600-2800 RPM 1A $375 I used promo code (278mm) to take off shipping
the guy said this TC would do the Job. INFO I GAVE:off roading, heavy loaded vehicle long trips, minimal towing (make sure you have trans cooler) at a later time 285/70-17 tires.

also keep in mind that even with a gear swap, its not going to feel the same. the 08+ modles have more gears in the trans.