Re-gearing for 33s

[Joe Banko]

I am currently running 31s on my TJ 2.5L 3 speed automatic, and the previous owner didn't regear it correctly. I was going to regear it anyway, but I was wondering if it is possible to go up to 33s or even 35s with the smaller engine. Also, what would the gear ratios be like? I've done a bit of research but only have found that 4.88 and up is good for a 5 speed, but haven't found much for 3 speeds.

 

[Rob5589]

What is in there now? For 33's, 4.56; 35's, 4.88. Either way with the 3 spd you will be spinning 3100 or so at 65. Personally I wouldn't run 35's on the 2.5 unless it was strictly an off road machine. Either way you are going to have to beef up the 35 with a Super 35 kit, some stronger axle u joints in front, better brakes, stronger steering, etc.

 

[glwood]

I am currently running 31s on my TJ 2.5L 3 speed automatic, and the previous owner didn't regear it correctly.

That's the main question - didn't regear it correctly by putting in what gears?

 

[Joe Banko]

What is in there now? For 33's, 4.56; 35's, 4.88. Either way with the 3 spd you will be spinning 3100 or so at 65. Personally I wouldn't run 35's on the 2.5 unless it was strictly an off road machine. Either way you are going to have to beef up the 35 with a Super 35 kit, some stronger axle u joints in front, better brakes, stronger steering, etc.

I'm actually not sure what is currently installed, but what would be a good daily driver ratio for the 31s? If I'm going to have to spin 3100 on the highway then I might just stick with what I have and possibly regear to 31s

 

[glwood]

If you're not sure what's in there, how do you know it was regeared by the previous owner?

 

[Jerry Bransford]

35" tires are too large for the Dana 35 rear axle that comes with all Wrangler TJs with the 2.5L engine, they'll snap a Dana 35 axle shaft.

For 33" tires and 3-speed automatic, I'd go with 4.56 gearing. 4.88 is the usual recommendation for 33" tires with the 2.5L engine but that's only for when you have the 5-speed manual transmission. Your 3-speed automatic doesn't have an Overdrive so you need a slightly higher ratio which would be 4.56 to keep the rpms at a reasonable speed for highway driving.

 

[Joe Banko]

Contacted the previous owner, and it is still stock gearing for the 205/75R15 Tires (27s)

 

[Rob5589]

Contacted the previous owner, and it is still stock gearing for the 205/75R15 Tires (27s)

Ok, but you still need to find out what the stock gearing is. There is usually a tag on the diff covers, front, rear, or both, that will have the ratio imprinted. It will be something like, 3.54, 4.10, etc.