Another re-gearing question

Flib

Flib

TJ Enthusiast
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Apr 15, 2018
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Nova Scotia
First question, 2004 TJ stock gearing, 3.73 or 3.07(?) or was either an option? The tags are not attached to the diff cover and I have yet to pop off the diff cover to have a look. Jeep is a dog on the road with the 33's.

Second question, if I wanted to go with 4.10 gears and it has 3.07's will I need to change the carrier? How about the 3.73's?
 
Not sure about the carrier, but for gears, assuming you have the 4.0, 4.56 for the stick, 5.13 for the auto.
 
Generally yes, you need to swap carriers. However, there are thick gear sets cut by some manufacturers that allow the high ratio carriers to run lower ratio gears.
 
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I thought IF the OP had 3.73's there would be no need for a new carrier unless he re-geared lower than 4.88?
 
JMT said:
I thought IF the OP had 3.73's there would be no need for a new carrier unless he re-geared lower than 4.88?
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3.73's in the 30 and 35 are good for lower gears. The 44 would need the 3.92 and lower carrier. There is not another carrier for lower than 4.88.
 
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Rob5589 said:
3.73's in the 30 and 35 are good for lower gears. The 44 would need the 3.92 and lower carrier. There is not another carrier for lower than 4.88.
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Thanks, that's a bit of knowledge I needed. Not as familiar with components outside of my Jeep!
 
You should be able to find out your stock gearing by looking on the tab bolted to the diff cover on your axles. Additionally, if you have your vin number handy follow the steps in the attached guide to get a build sheet of your jeep.

http://jeepsies.com/jeep-build-sheet/
 
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You can quickly determine your axle ratio by jacking up one side of the rear axle and rotating a wheel twice while counting the number of rotations the driveshaft makes. After doing jacking up one side, shift the transfer case into Neutral. Then put a mark or a bit of tape on the rear driveshaft so you can count how many turns it makes. Rotate the wheel precisely two turns and note whether the driveshaft rotated 3 times or nearly 4 times... 3.07 or 3.73 times. You can also read about the procedure at http://jedi.com/obiwan/jeep/misc/gearratio.html

Or you can note the rpms your engine produces at some exact speed like 65 mph and together with giving us those rpms plus your exact tire size and which transmission you have, we can calculate your axle ratio.
 
Rob5589 said:
3.73's in the 30 and 35 are good for lower gears. The 44 would need the 3.92 and lower carrier. There is not another carrier for lower than 4.88.
Click to expand...

Thanks Rob, this is a Dana 35 I am talking about so I could go from 3.73 to 4.10 without swapping the carrier?
 
Jerry Bransford said:
You can quickly determine your axle ratio by jacking up one side of the rear axle and rotating a wheel twice while counting the number of rotations the driveshaft makes. After doing jacking up one side, shift the transfer case into Neutral. Then put a mark or a bit of tape on the rear driveshaft so you can count how many turns it makes. Rotate the wheel precisely two turns and note whether the driveshaft rotated 3 times or nearly 4 times... 3.07 or 3.73 times. You can also read about the procedure at http://jedi.com/obiwan/jeep/misc/gearratio.html

Or you can note the rpms your engine produces at some exact speed like 65 mph and together with giving us those rpms plus your exact tire size and which transmission you have, we can calculate your axle ratio.
Click to expand...

I'll have to give that a go, thanks Jerry.
 
Flib said:
I'll have to give that a go, thanks Jerry.
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If you do this, really pay attention to where you start the mark on the drive line and where it ends up. because 3:73 and 4:10 look close after two revolutions of the tire. One is just before the final revolution of the drive line and one is just after. Might have to do it twice to make certain, and a third time is a science!
 
Rob5589 said:
Correct.
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so how about 3.73 to 5.10?? Carrier swap then or is there a "thick" set available (I think that is the correct term)?

I have 3 different options at this point, one is more expensive but gives me 4.10 gears and requires less of my time (with a new baby due any day this is a major plus).

They other 2 options are cheaper but require me to get new spring perches and weld them on, the cheapest option would see me keep my current gears and then have to re-gear at a later date. This would permit me to go to 5.10 gears but that would not be cheap either especially if I had to replace the carriers.
 
Flib said:
so how about 3.73 to 5.10?? Carrier swap then or is there a "thick" set available (I think that is the correct term)?

I have 3 different options at this point, one is more expensive but gives me 4.10 gears and requires less of my time (with a new baby due any day this is a major plus).

They other 2 options are cheaper but require me to get new spring perches and weld them on, the cheapest option would see me keep my current gears and then have to re-gear at a later date. This would permit me to go to 5.10 gears but that would not be cheap either especially if I had to replace the carriers.
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The carrier break is 3.31 and down, 3.54 and up. So if you have 3.73 it will accept anything lower.
 
Jerry Bransford said:
You can quickly determine your axle ratio by jacking up one side of the rear axle and rotating a wheel twice while counting the number of rotations the driveshaft makes. After doing jacking up one side, shift the transfer case into Neutral. Then put a mark or a bit of tape on the rear driveshaft so you can count how many turns it makes. Rotate the wheel precisely two turns and note whether the driveshaft rotated 3 times or nearly 4 times... 3.07 or 3.73 times. You can also read about the procedure at http://jedi.com/obiwan/jeep/misc/gearratio.html

Or you can note the rpms your engine produces at some exact speed like 65 mph and together with giving us those rpms plus your exact tire size and which transmission you have, we can calculate your axle ratio.
Click to expand...
I do this taping a string to the driveshaft and counting the wraps. Easier if yer alone.
 
son of a ,,,,, it has 3.07's. No wonder it is such a dog on the road.

I want to go to 4.88's so I guess I need to find a new carrier?
 
Flib said:
son of a ,,,,, it has 3.07's. No wonder it is such a dog on the road.

I want to go to 4.88's so I guess I need to find a new carrier?
Click to expand...
Booo, 3.07. There may be a thick gear set available but open carriers are relatively cheap if not. Of course now is the time if you want traction devices.
 
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