$5000 Truck I bought.

dodge man · Aug 30, 2010

If anybody read my thread from a couple of weeks ago, I was looking at trading my 2007 Ram for a Dodge Challenger, and them buying a $5000 truck to replace the Ram. We did the deal for the Challenger this last Saturday, and bought a truck today. The $5000 truck turned in to a $8800 truck. It is a 2002 GMC half ton, 100,000 miles, 4x4 regular cab, 5.3l V8. Its in excellent shape for its age and miles.

I have one question, how do you determine the rear gear ratio. The truck has the tow package. In the past I have spun the rear tires and counted the revoloutions of the drive shaft. I did it several times, and got 2 spins of the driveshaft for one of the tire. This doesn't seem possible. I've never hear of rear gears much taller than a 2.7 to 1. Am I doing something stupid when I spin the tires and count the drive shaft revs? Is there some kind of code on the truck that tells? At times they have put tags on the rear ends, but I couldn't find one.

BTW, I love the Challenger.

bp fick · Aug 30, 2010

What gear ratio do I have in my GM or Chevrolet rear end, do I have positraction - Drivetrain.com

Page down this web page. You'll find what you are looking for.

Diamondpilot · Aug 30, 2010

Spinning the rear end does not work like it used to now with some having the lockers, ect. Many GM's you have to do what you have done and multiply it by 2.

According to my tow book a 2002 reg cab 1/2 ton 4x4 GM with the 5.3L has only one gear option, and thats 4.10. That makes your math work with 2 revolutions times 2. That gives you a tow rating of 8,800#. Not to shabby for that old of a truck.

We now need pictures.

Chris

Diamondpilot · Aug 30, 2010

You know, now that I posted it seems odd. Many GM's of the early to mid 2000's had a 3.42 gear that was pathetic. The tow rating was around 6,500#. They also had a 3.73 gear that was much better but I do not remember many 4.10 gears. Maybe there was and since that is the only gear my book list on a reg cab 4x4. They may have just put them in reg cab 4x4's which to be honest cant say if I have ever dealt with one. Most of my customers have extended cab and crew cab trucks.

If so that will be a good truck for what you want. I had a 01 F-150 4x4 with 4.10 gears and it was a towing beast. Did not matter what you had behind it I always averaged 14mpg.

Chris

dodge man · Aug 30, 2010

Its is code GT4, which is a 3.73. It also says "(DUP WITH 5 X 1)" , which I don't know what that means. Thats pretty good ratio, it could be worse.

The guy I bought it from said it was a posi, but it doesn't have code G80, and when I did a little burn out, it only spun one tire. I don't think the guy lied to me, but he probably doesn't have a clue one way or the other. So far I found a slight leak in the windshield, and thats it.

I'll post some pictures in the next few days.

Thanks for the responses and links.

czechsonofagun · Aug 31, 2010

Well you are going to replace all fluids, right? Just count teeth on ring and pinon and you will know the ratio:thumbsup:

doall · Aug 31, 2010

the only time a Z 71 is a locker is if it is in 4 low. Limited slip in 4 high or 2 high.
My 03 has 3.73 ratio. The 4.10's really make for a much more capable truck.

scoutcub · Aug 31, 2010

Good deal. Does this mean an avatar change??

And, might as well throw in some pics of the challenger....

Dmace · Aug 31, 2010

Forget the pics of the truck, I want pics of the Challenger! :thumbsup:

jwstewar · Aug 31, 2010

doall said:
the only time a Z 71 is a locker is if it is in 4 low. Limited slip in 4 high or 2 high.
My 03 has 3.73 ratio. The 4.10's really make for a much more capable truck.

This is wrong. If the truck has a G80 - and Dodge Dude's doesn't. It will lock when it senses and 200 RPM difference in wheel speed and you are going less than 20 MPH. I've owned 5 different vehicles with the G80 and haven't had a problem with any of them. Some places you will hear people bad mouth them and call them Grenade 80s, but I think these people could tear up anything. Use them right and don't abuse them and they will last a good long time.

Diamondpilot · Aug 31, 2010

dodge man said:
Its is code GT4, which is a 3.73. It also says "(DUP WITH 5 X 1)" , which I don't know what that means. Thats pretty good ratio, it could be worse.

The guy I bought it from said it was a posi, but it doesn't have code G80, and when I did a little burn out, it only spun one tire. I don't think the guy lied to me, but he probably doesn't have a clue one way or the other. So far I found a slight leak in the windshield, and thats it.

I'll post some pictures in the next few days.

Thanks for the responses and links.

The 3.73 gear seem right. When my book listed 4.10 as the only gear it just did not seem right as I posted above. I have seen many of these trucks and installed hitches, brake controllers, ect and have never seen a 4.10 gear ratio on a GM 1/2 ton.

Glad its the 3.73 and not that 3.42 gear. It would not be a good tow rig with that. GM loves to play the MPG game so they can brag with that 3.42 gear but does not do them any justice when it comes to lugging a load.

Chris

Diamondpilot · Aug 31, 2010

jwstewar said:
This is wrong. If the truck has a G80 - and Dodge Dude's doesn't. It will lock when it senses and 200 RPM difference in wheel speed and you are going less than 20 MPH. I've owned 5 different vehicles with the G80 and haven't had a problem with any of them. Some places you will hear people bad mouth them and call them Grenade 80s, but I think these people could tear up anything. Use them right and don't abuse them and they will last a good long time.

You are right. Its totally automatic unlike my Detroit Locker I have front and rear that I must engage with a switches. They are electric lockers.

The G80 is crude compared to other lockers on the market but works pretty good. Biggest draw back is it only works upto 20 mph of rear wheel spin, not trucks speed, and it makes a clunking noise when it goes in and out. I would still take one any day of the week over a truck without a locker. There is just no comparison.

Chris

dodge man · Aug 31, 2010

How easy is it to hook up a brake controller? I'm almost positive it has the factory tow package. Does is just need a controller and a pig tail to hook up under the dash? I'm probably going to order a brake controller for it and might as well get everything I need at that time.

I will post picks of both the Challenger and the GMC soon. I work full time and have been running around lately taking care of insurance and such.

Change my Avatar from Dodge Man? Thats a good one!:laughing:

Diamondpilot · Aug 31, 2010

Here is the instructions on how to hook up a brake controller. You can order all you need from Paul and his wife and they are not to far from you. I have always gotten great service and prices.

R and P Carriages, Towing and trailer help questions

Chris

bp fick · Aug 31, 2010

My experience with factory towing packages is that they include the receiver, the wiring harness and sometimes also include a trans cooler, thicker radiator, and sometimes even a power steering cooler. YMMV. The brake controller was never included, of course.

There is nothing worse to drive than something geared wrong. Maybe "right" for mpg at a steady 70 mph on flat ground, but the real world doesn't include that scenario very often. 3.5x 3.7x 4.1x

Had a truck, briefly, with a mpg marketing fiasco rear end of 3.05
Useless.

Dodge, you're gonna enjoy that truck and it sounds like you got a good deal on it. Congrats.

CinderSchnauzer · Aug 31, 2010

Go to your GM Parts counter. Give them the VIN and they can print a build sheet showing all the codes and description. then you'll know exactly what you have.

bdeboer · Aug 31, 2010

dodge man said:
How easy is it to hook up a brake controller? I'm almost positive it has the factory tow package. Does is just need a controller and a pig tail to hook up under the dash? I'm probably going to order a brake controller for it and might as well get everything I need at that time.

!:laughing:

Buy a Tekonsha Prodigy and the correct harness for a 2002 GM, and it will plug in on both ends. If you have the factory tow package there should be a 7 wire plug and receiver hitch on the back of the truck.

Ford tractor · Aug 31, 2010

dodge man said:
How easy is it to hook up a brake controller? :

2 screws and a wire plug. You do have to level the box, but it's very simple with the tow package.

At some point around 2003 (I think) GM changed the wireout and the old harness used in the new truck would cause the brakes to come on with the headlights. Talk about a surprise when entering a tunnel!

dodge man · Sep 1, 2010

I ordered a Tekonsha Prodigy last night and a harness to hook it up, something like a $150 to the front door. It should be an easy hook up.

Diamondpilot · Sep 1, 2010

Go to the link I posted earlier and they have all the info you will need under GM Trucks. Just click the right year. Some trucks need a relay and fuse installed to make the controller work and to get the charge function working on the 7 pin plug.

Chris