Chevy Silverado Z-71

[Tim D]

I have an 03 Z-71 1500. When I bought it I had the hitch installed as well as the plug. When I bought the TT I took it in to have the transmission serviced as well as have a transmission cooler put on. The shop said it already had one. So...I don't really know if it came with a "tow package" or not. I am guessing no since I had to do the above. Anyway, my question is this: What would be the optimal gear ratio for this truck? How can I tell what it has? Can it be changed reasonably? What about lift bags? Recommendations besides a new tow vehicle? This one is paid for and would like to get a couple more years out of it.

[dalemac377]

You should be able to determine all your truck's spec by researching the VIN#. You can change differential gears for more towing capacity. Cost will be higher if you have four wheel drive, two sets of gears. Several years ago I had my dealer change my '01 GMC 2wd differential to a 3.73. It cost me about $900.00.

[fhenn]

Also in the glove box, there is a sticker that has a list of all of the build codes. the rear end code will be there. Though I would think the the easiest method would to take the vin down to GM and have the run it that will give all of the options and rear end also

[anaro]

you can change gear ratio and add aIr bags but it does not increase your tow capacity. you will still be limited by gvwr. in fact air bags will add weight and technically decrease your available payload and towing capacity. like it or not you are limited by payload. the only thing that will change that is another tow vehicle. I also had a paid for tow vehicle that I kept trying to make work. I kept throwing money at it but in the end I gave up and got the bigger stronger tow vehicle. I bought it used saving some $$$ that way but I sure wish I hadn't thrown thousands into the old TV. just my 2 cents from having been there, done that.

[ewbldavis]

With a Z71, I would be surprised if diff is other than a 3.73.

Check glove box to be sure as Frank suggested. You can google build codes for rear end (that is how I confirmed our Trailblazer rear end).

You likely had tranny cooler as part of the Z71 package. Generally, the Z71's are setup for towing already, except some don't have hitch.

I agree, too, with Anaro. Don't dump a ton of money into a 10-year old truck. Especially rear end, as you will need to change front differential, too. You can easily have $3000 in it to change gear ratio on your truck.

Another question: Does it matter? Your truck, even if equipped with a 3:42 rear end, should be more than adequate for the ST25RB.

[Beamer5]

The Z-71 almost all come with 3.73 and tranny cooler. You could change to 4.10 or something along those line, but with a 4x4 it will be expensive and not worth the small gain in performance IMHO. Just save the cash for your next TV.

[Tim D]

Was'nt even thinking I would need to do more than the rear. I think I will leave well enough alone. I tows fine, not a speed demon by any means, nut a new truck is not in the budget right now. Thanks everyone.

[dalemac377]

Good luck and enjoy your camping Tim.

[2slick]

Originally Posted by Tim D

Was'nt even thinking I would need to do more than the rear. I think I will leave well enough alone. I tows fine, not a speed demon by any means, nut a new truck is not in the budget right now. Thanks everyone.

I would say you made a good decision. I had a 2003 Silverado with camper package.....4:10 gears and 6.0 engine. Towed a 28' TT with it. I never liked to lose speed on hills, so I went to a Duramax. Best decision I ever made on a truck.

[Tim D]

Originally Posted by 2slick

I would say you made a good decision. I had a 2003 Silverado with camper package.....4:10 gears and 6.0 engine. Towed a 28' TT with it. I never liked to lose speed on hills, so I went to a Duramax. Best decision I ever made on a truck.

Well...that is my only problem with it. I do drop speed in the hills. Hoping to travel further from home next year, involving some mountain driving. Will just have to see how it does.

[ewbldavis]

Speed...why hurry. Enjoy the drive. It is why we all camp! Getting there is half the fun!

[Tim D]

Originally Posted by ewbldavis

Speed...why hurry. Enjoy the drive. It is why we all camp! Getting there is half the fun!

I understand that is the whole point. However, with time off as a premium I find I want to get to my destination as quickly as I can so I can "Enjoy" myself. Then when time has run out I want to get home. LOL

[anaro]

Originally Posted by Tim D

I understand that is the whole point. However, with time off as a premium I find I want to get to my destination as quickly as I can so I can "Enjoy" myself. Then when time has run out I want to get home. LOL

x2..... I will enjoy the driving more when I'm retired and not hauling a 6 yr old around in the car.

[ewbldavis]

X3 Anaro...BTW, are we there yet?

[sking]

Z71 is 4wheel drive, you'd need to do front and back for about $750 each. You should be just fine as is, I'd simply check the weight rating of your hitch. I've had to repair and gusset a few Chevy rear frame rails do to overloaded hitches that have torn the rear frame rails.

[NorskeNY]

For towing you would want a 3:73 or 4:10 rear end - - as indicated above there is a sheet glued to the inside of the glove box with all of the truck build codes
I found this: GU6 = 3.42, GT4 = 3.73, or GT5 = 4.10
here are all of the codes:
http://www.sierragear.com/gm-rpo-axl...ation-codes-3/



Air bags will help with the ride when hitched - you will need to adjust the hitch bars - someone with bags and an equalizer hitch can give you some hints.

You could always increase the size of the tranny cooler. If the tranny takes Dexron 6 tranny fluid - switch to a synthetic fluid. I use TranSynd in my Allison tranny.

TES 295 approved fluids:
Castrol - - TranSynd
BP - - Autran Syn 295
Cognis Corporation - - Emgard 2805
International - - Fleetrite Synthetic ATF
ExxonMobil - - Mobil Delvac Synthetic ATF
John Deere - - HD SynTran
Volvo - - Bulldog Synthetic ATF


Put some Bilstein shocks on the truck - my OEMs were shot after 22,000 miles.


Remember that the trailer tires are only rated for 65 mph. Always keep them properly inflated to minimize the chance for a blow out.


The Z71 is the suspension package - mine has the Z85. Z85 = Heavy Trailering Package

Z71 "OFF ROAD" CHASSIS PACKAGE 'OFF ROAD' CHAS PKG

You should find something like this in the glove box

[sking]

Z 71 comes will Bilstein shocks doesn't it??

[Shoalwater]

X amillion Anaro, I have a 5 year old, 3 year old, and another that will be here in February(Wife is finally getting her little baby girl). It's tough for them on long trips to sit still, even with DVD players to help pass the time.

[anaro]

Shoal water- Congrats on the soon to be new addition!

[vmathias]

I have a 2011 Silverado with the tow package. the Tran cooler it came with was not very big, maybe 2" x 12". Tran temp was hitting 240 on some of our smaller hills here in Colorado. I Talked to the local transmission guy and went with the biggest one that would fit, maybe 6" x 24" for less than $300. Now the tran tem doesn't go over 210 on the biggest mountians. My understanding is that you can't over cool your tran. Go big if you can, New or rebuilt transmissions are expensive.