[jdp8402]

How do I tell what my gear ratio is? Is there a way to count them? Also what gear ratio should I have to run 35's? I believe the front axle is a 30 and the rear is a 44. Is that correct?

Thanks,
Jeff

 

[jdp8402]

Maybe I should mention that it's an automatic also. Not sure if that will make a difference on the gearing.

 

[Jerry Bransford]

To know for sure, count the number of teeth on the ring gear and divide that by the number of teeth on the pinion gear.

But to cut to the chase, the factory installed 3.73 into your TJ. That's what all TJs with a front Dana 30 and rear Dana 44 came with. Only if a previous owner regeared it to a different ratio would it not be 3.73.

 

[Joey330]

35s and an auto 5.13

 

[jdp8402]

Thanks for the replies. Do I only need to replace the ring and pinion gears or should some other parts be upgraded while I'm in there?

 

[Sneakynut]

Thanks for the replies. Do I only need to replace the ring and pinion gears or should some other parts be upgraded while I'm in there?

you'll need to get a master install kit for both the front and rear axles. This will give you all new bearings which is always recommend when doing a gear change!

 

[Water Dog]

If you are talking about the "98" in your profile, you have a three speed auto. If that is the case, I believe you want 4.56 gears with the 4.0L and 35's...Jerry B. can correct me if I'm wrong. I think he used to run the 3 speed auto.

If you have never done gears, have a shop do it...there's a lot more to setting up gears than just replacing parts.

 

[Jerry Bransford]

Yep the correct ratio to run 35's depends on which automatic is installed. For 2002 and older TJs that have the 32RH 3-speed automatic, 4.56 is appropriate for 35's. For 2003 and newer with the 4-speed automatic, 5.13 or 5.38 would be ideal but he has the Dana 30 front axle which can currently only be geared to 4.88. The good news is that Revolution Gear & Axle is currently testing 5.13 for the Dana 30 so that will be available before not too much longer.

 

[nathan36]

Yep the correct ratio to run 35's depends on which automatic is installed. For 2002 and older TJs that have the 32RH 3-speed automatic, 4.56 is appropriate for 35's. For 2003 and newer with the 4-speed automatic, 5.13 or 5.38 would be ideal but he has the Dana 30 front axle which can currently only be geared to 4.88. The good news is that Revolution Gear & Axle is currently testing 5.13 for the Dana 30 so that will be available before not too much longer.

yes I emailed Revolution Gear & Axle at the beginning of this month and they did tell me they have TESTED the 5.13s in a TJ Dana 30 and are in production! Should be available at the end of this month!

 

[jdp8402]

Yes I'm talking about the "98" in my profile. Automatic with the 4.0L. I bought the Jeep with 35's on it and it came with 5 other matching 35's with rims. So I don't want to change the tires. Plus I like the look of the 35's. I recently put on a SYE (had a mechanic do it). There's a bunch more stuff I have to do yet. One of which will be a new lift. But for now I'm putting money where it's needed. It's kind of became my daily driver just because I love driving it, but I still want to be able to offroad with it. I need to make it mechanically dependable before I buy a bunch of other mods for it. Is revolution gear and axle a good company to go with?

Thanks again for all the replies,
Jeff

 

[nathan36]

Yes I'm talking about the "98" in my profile. Automatic with the 4.0L. I bought the Jeep with 35's on it and it came with 5 other matching 35's with rims. So I don't want to change the tires. Plus I like the look of the 35's. I recently put on a SYE (had a mechanic do it). There's a bunch more stuff I have to do yet. One of which will be a new lift. But for now I'm putting money where it's needed. It's kind of became my daily driver just because I love driving it, but I still want to be able to offroad with it. I need to make it mechanically dependable before I buy a bunch of other mods for it. Is revolution gear and axle a good company to go with? Thanks again for all the replies, Jeff

yes since you have the 32RH transmission you will want to go with 4.56 gears with those 35s! Also, if you have a dana 35 in the rear you may want to look into ditching that axle. And Revolution gear and axle is a good company there are some other ones too hopefully others will chime in.

 

[Water Dog]

He has a D44 in the rear...see picture in first post.

 

[jdp8402]

Sorry the pictures are sideways. Don't know what happened. I've read on here to get rid of the drop pitman arm. Why do they send them with lift kits if you shouldn't use them? The previous owner put on a 4" skyjacker lift. If I go back to a stock pitman arm is there anything else I'll need there?

 

[FloridaRunner]

Sorry the pictures are sideways. Don't know what happened. I've read on here to get rid of the drop pitman arm. Why do they send them with lift kits if you shouldn't use them? The previous owner put on a 4" skyjacker lift. If I go back to a stock pitman arm is there anything else I'll need there?

There will probably be a track bar relocation bracket or its just relocated. If you do, you can buy an adjustable track bar and mount it in the factory location. That should have your angles right.

 

[Water Dog]

Sorry the pictures are sideways. Don't know what happened. I've read on here to get rid of the drop pitman arm. Why do they send them with lift kits if you shouldn't use them? The previous owner put on a 4" skyjacker lift. If I go back to a stock pitman arm is there anything else I'll need there?

Dropped pitman arms are a left over mod from YJ's leaf spring suspension. They are not needed and actually detrimental to a TJ. Maintaining correct steering geometry means keeping the line formed by the drag link ends and the track bar ends as parallel as possible. Installing a dropped pitman arm without dropping the track bar by the same amount takes the two further from parallel, and there is no point to dropping them both. Here's a visual.

The first picture is with a stock pitman arm and adjustable track bar, and the second is with a dropped pitman arm. When you get the angles this far off, you will have bump steer.

 

[jdp8402]

Thanks for the visual. It really helps someone like me that doesn't all the termanology yet. I'm still in the learning phase. They say a picture is worth a thousand words.

 

[Little_Willy]

2 questions to add to this thread:

1. What is bump steer?

2. If I have a 2000 TJ with D30 in front and D44 in the rear, would a 4.56 be sufficient for 35s? I know I would have to upgrade some steering and braking components.

 

[FloridaRunner]

2 questions to add to this thread:

1. What is bump steer?

2. If I have a 2000 TJ with D30 in front and D44 in the rear, would a 4.56 be sufficient for 35s? I know I would have to upgrade some steering and braking components.

1. When you hit a bump or a dip, your axle will pivot. It's connected to your drag link that steers and the track bar that centers the axle and is connected to the frame or body (I don't know, just kinda regurgitating what I remember). The drag link and track bar are yellow and green respectively in Water Dog's picture. When the axle pivots, it is restrained by either bar and the axle shifts forward or backwards causing the steering to turn to the side. If you can picture that, it makes sense haha.

2. Yes, I think as stated by Jerry, the 3-speed auto and 5-speed manual would need 4.56 gears.

 

[Little_Willy]

1. When you hit a bump or a dip, your axle will pivot. It's connected to your drag link that steers and the track bar that centers the axle and is connected to the frame or body (I don't know, just kinda regurgitating what I remember). The drag link and track bar are yellow and green respectively in Water Dog's picture. When the axle pivots, it is restrained by either bar and the axle shifts forward or backwards causing the steering to turn to the side. If you can picture that, it makes sense haha.

2. Yes, I think as stated by Jerry, the 3-speed auto and 5-speed manual would need 4.56 gears.

Thanks for the explanations. Thant makes perfect sense.