Need Help Determining Gear Ratio

[Bumblebee]

Trying to determine the axel Ratio on my 2006 TJ so I can change out my speedo gear. I previous thread said I can determine from the tag on the Differential. T

he number is 52132355AA second Line is 07-2006280 -2. So, can anyone tell me what the axel ratio is?? Thanks

Denny

 

[lindsey97]

Chock your wheels, jack the rear of the jeep upon a flat hard surface, making sure it can't roll or fall.
Place a mark with paint or whatever in the 12 o'clock position. Place a mark on your rear driveshaft in the 6 o'clock position.

Rotate the driveshaft by hand, counting the turns of the driveshaft carefully, until the wheel with the mark makes on complete revolution.

For example, if you get 3 3/4 driveshaft turns to 1 turn of the wheel, then you have 3:73 to 1 gears.

 

[tworley]

I see .07 towards the top...3.07 gears

 

[cliffish]

Why get the free build sheet, if it stock it will tell you exactly how it left the factory, options and all.

Copy the rest of the link and type your vin in where it says XXXX:
https://www.jeep.com/webselfservice/BuildSheetServlet?vin=XXXX

 

[softballnrd27]

That link no longer works as far as I know.
Go to this website:
https://fcacommunity.force.com/Jeep/s/
select FAQ
select most popular
Select how do I get a vehicle equipment list
Select Equipment Listing in the text

https://fcacommunity.force.com/RAM/s/equipment-listing

 

[cliffish]

you are correct - thanks for checking

 

[Bumblebee]

Thanks guys. That works. It has 3.07 gears and was suggested by tworley. Also, Equipment Listing is good to have with the rest of the documentation.

 

[Jerry Bransford]

3.07... an abysmal ratio, I can only think of one or two people I would wish that ratio on.

 

[99jeeper]

give me the last 8 of your vin #. I work at a Chrysler/Jeep dealer and I can get it for you

 

[Bumblebee]

3.07... an abysmal ratio, I can only think of one or two people I would wish that ratio on.

Jerry, Can you elaborate on this please????

 

[Bumblebee]

give me the last 8 of your vin #. I work at a Chrysler/Jeep dealer and I can get it for you

I got it Jerry. It sems to be 3,07. If toy disagree , let me know' Last 4 of the vin is 6430

 

[Rob5589]

Jerry, Can you elaborate on this please????

3.07 is too tall a ratio, especially for over sized tires. What transmission do you have?

 

[Bumblebee]

3.07 is too tall a ratio, especially for over sized tires. What transmission do you have?

6 speed manual

 

[Rob5589]

6 speed manual

Of all the available transmission/3.07 combos, that is probably the best of them all due to the lower gearing. But it still is a poor combo, especially with the larger tires you are running.

 

[Jerry Bransford]

Jerry, Can you elaborate on this please????

3.07 produces such a low engine rpm while driving that the engine struggles to produce enough power with any tire size other than the very smallest size possible. Once larger tires are installed the driving experience becomes miserable due to the engine rpms not being enough to keep up with traffic, accelerate, or even make it up even a gentle grade without needing to downshift excessively or needing to stay in a lower gear like 4th with a 5-speed to maintain your speed.

 

[AndyG]

This is a pretty typical scenario.

Someone inherits the larger tires someone else put on the vehicle... Then they drive the Jeep and they don't have any reference point of how far off the gearing is because they never drove the Jeep stock.

With those 32 inch tires, 4:10 would be pretty good or 4:56 but I would defer to Rob.

There's not a thing wrong with your Jeep so we're not being critical... It's a fine example of a well-cared-for TJ... The larger tires look cool and many people don't realize that they affect the gearing which hurts the performance the mileage and to some extent the clutch.

 

[billiebob]

Had an '87 with 33s and 3.07s. I never used 5th gear but it would cruise all day at 75 in 4th and deliver 20mpg. The best part of 3.07s was 4LO. It was like a Mustang on forestry roads and could hit 60mph. It was a great daily driver. I think I sold mine with 250K miles on it.

 

[Bumblebee]

Thanks fellas. I really haven't noticed too much of the issues you are describing, however, I have only logged about 1800 miles since I bought it. It is pretty flat here in northern Ohio so I haven't experienced cruising up and down mountains and having to downshift all the time. I can say that I very seldom get into 6th gear. I can maintain the speed limit without 6th most of the time.

 

[Rob5589]

Thanks fellas. I really haven't noticed too much of the issues you are describing, however, I have only logged about 1800 miles since I bought it. It is pretty flat here in northern Ohio so I haven't experienced cruising up and down mountains and having to downshift all the time. I can say that I very seldom get into 6th gear. I can maintain the speed limit without 6th most of the time.

All due to the super tall gearing and over sized tires. You want to be running approx 2600-2800 rpm at 70 (ish) in 6th. For your combo 2800 is 105 mph

 

[billiebob]

Unless gas mileage is a concern in which case cruising at 2000rpm is ideal. I get 20mpg if I stay under 60mph with 33s and 4.10s. At 75mph I'm lucky to get 15mpg.

I got over 20mpg at 75mph with 33s and 3.07s in 4th gear with my YJ.

3000rpm is the sweet spot for performance with a TJ but 2000rpm is the sweet spot for gas mileage.