5.13 Gears, My Thoughts and Real Numbers

[JTenn]

Dana 5.13 gears with rebuild kit ordered from NR4x4 this morning now that they're back in stock (sweet Jesus, finally). Going to wait a little bit to have them installed as I'd like to see what Jeep plans to do with the stock clutch before I order a Center Force replacement, as I'd like to do it all at the same time.

JTR/6MT/35s

Awesome!! You won't be disappointed.

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[Panthers65]

Dana 5.13 gears with rebuild kit ordered from NR4x4 this morning now that they're back in stock (sweet Jesus, finally). Going to wait a little bit to have them installed as I'd like to see what Jeep plans to do with the stock clutch before I order a Center Force replacement, as I'd like to do it all at the same time.

JTR/6MT/35s

Yep, received m shipment from NR4x4 this afternoon for the rear. I've had the front for a while. I ordered back on Black Friday in November, call it 4.5-5 months.

Originally Dana told NR4x4 they wouldn't manufacture them until June-July, so it was a nice surprise when I got the notification yesterday they shipped. My $150 GC got in my mailbox about 20 minutes after UPS dropped the gears off.

Now to install.....

 

[gt3mike]

I recently changed to 5.13 on my JTR with 35s. I've driven close to 700 miles, and the transmission is still unhappy. It's holding gears unnecessarily (for example yesterday I needed to force it to upshift from 5th to 6th at around 70mph). Also it sometimes shifts down to 1st gear when stopping, which can be abrupt.

Yes, I updated the computer for the 5.13 gear ratio. Twice.

Did anyone here that changed to 5.13 gearing and has a happy transmission do anything to reset the transmission "memory"? If so, what did you do? I can take it to Jeep, but that path usually leads to frustration.

I thought I'd post an update just for the benefit of others that might have this question in the future. It took somewhere between one and two thousand miles, but the transmission eventually learned how to behave with the new gearing and settled down. Now it shifts all the way up into 8th gear without any coaxing, and downshifting is predictable and smooth.

 

[JTenn]

I thought I'd post an update just for the benefit of others that might have this question in the future. It took somewhere between one and two thousand miles, but the transmission eventually learned how to behave with the new gearing and settled down. Now it shifts all the way up into 8th gear without any coaxing, and downshifting is predictable and smooth.

I love the 5.13's. They completely changed the driving/off roading/ general enjoyment factor for me. So glad I have them.

 

[Wheelin98TJ]

When I arrived at work this morning after a 50 mile trip at 70-75 mph, I crawled under the truck and laid hands on my diff. I began praying and..........lol, just kidding. Seriously though, it was, my best guess about 130 degrees. I could easily touch and leave my hands in contact with the diff. This to me doesn't seem like excessive heat but I'm not sure what a differential normally runs. I would definitely think the oil would be rated for much higher Temps though. I will probably plan to change the oil every 15000 miles although I think that's more than it needs. I'll lean towards the side of caution though.

This is a fun tool to have.

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[JarHeadLV]

Im "new" to Jeeps, but from all the reading/videos I've seen and watched lately 5.13 gears are NOT what I see the "experts" recommending for 35's. They are usually even recommending 4.88's for 37's. Curious why you went to 5.13's?

 

[AustinL911]

Im "new" to Jeeps, but from all the reading/videos I've seen and watched lately 5.13 gears are NOT what I see the "experts" recommending for 35's. They are usually even recommending 4.88's for 37's. Curious why you went to 5.13's?

1. Who are the experts? Most of these posts are anecdotal by common users.
2. Have you EVER heard a single person complain about over-gearing? It pretty much never happens.
3. It's transmission-dependent as well. The AT is far more adaptable to being under-geared than the MT is.

 

[JarHeadLV]

1. Who are the experts? Most of these posts are anecdotal by common users.
2. Have you EVER heard a single person complain about over-gearing? It pretty much never happens.
3. It's transmission-dependent as well. The AT is far more adaptable to being under-geared than the MT is.

1. Slow your roll bro.

2. I'm merely asking from what I've read/watched. The Popular guys on Youtube, Like Exodus Jeeps, etc... are the "experts" that I'm talking about. Tire/wheel/gear guys on youtube is where I've seen alot of this info from.

3. Actually, YES, I watch [Banned Site] alot (I like his channel) and he put 5.13's in one of his Jeeps and said in his video he thinks its a little too much.

 

[AustinL911]

Slow your roll bro. I'm merely asking from what I've read/watched. The Popular guys on Youtube, Like Exodus Jeeps, etc... are the "experts" that I'm talking about. Tire/wheel/gear guys on youtube is where I've seen alot of this info from.

Sorry, didn't mean for it to come across as adversarial.

 

[JarHeadLV]

Sorry, didn't mean for it to come across as adversarial.

cool. So, getting back to the question. I can only go by what these people who do tires/wheels/gears all day long reccommend.

 

[JTenn]

Im "new" to Jeeps, but from all the reading/videos I've seen and watched lately 5.13 gears are NOT what I see the "experts" recommending for 35's. They are usually even recommending 4.88's for 37's. Curious why you went to 5.13's?

I have a Willys that came with factory limited slip rear and open front differentials. I wanted lockers and found someone selling Rubicon take offs. Complete axle assemblies front and rear. They already had 5.13's installed. That's how I came onto them and I'm so glad I did. I am still currently on 35's but will move to 37's for my next set of tires. The 5.13's just effortlessly go to 8th gear and actually run the same to slightly lower rpm on the highway.

 

[bleda2002]

Im "new" to Jeeps, but from all the reading/videos I've seen and watched lately 5.13 gears are NOT what I see the "experts" recommending for 35's. They are usually even recommending 4.88's for 37's. Curious why you went to 5.13's?

One thing to consider is that you have jls and jts and they often get lumped together in terms of gearing advice. The JT is heavier, usually carries more, and tows so it benefits from deeper gears more than the jl where the pentastar is still a dog but at least adequate.

Personally 5.13s seem like a great sweet spot for anything from 37s to 39s. A little over kill for 35s but if people don't mind a few hundred extra rpm on the highway it will still do just fine. Another thing to consider is that 5.13s turn 8th in to the current 6th more or less, so if you are running 6th most of the time on the highway the 5.13s won't really be running any higher rpm at 8th but give you a whole lot more grunt.

 

[JTenn]

One thing to consider is that you have jls and jts and they often get lumped together in terms of gearing advice. The JT is heavier, usually carries more, and tows so it benefits from deeper gears more than the jl where the pentastar is still a dog but at least adequate.

Personally 5.13s seem like a great sweet spot for anything from 37s to 39s. A little over kill for 35s but if people don't mind a few hundred extra rpm on the highway it will still do just fine. Another thing to consider is that 5.13s turn 8th in to the current 6th more or less, so if you are running 6th most of the time on the highway the 5.13s won't really be running any higher rpm at 8th but give you a whole lot more grunt.

Exactly my experience. It will only improve when I move to 37's.

 

[JTenn]

The pics at the beginning of this thread are real world highway speeds/RPM's. The rpms don't seem out of line or high to me. But I don't remember how they were when it was bone stock. It wasn't stock for very long.

 

[JarHeadLV]

Keep in mind Im NOT coming from an "experience" point of view like I'm an expert, just relaying what I've seen over and over from these people in the biz.

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