Forum advice vs shop advice: Are 5.38 gears to low for Dana 44?

[Powdermonkey]

As a newbie how does one determine which way to go?

Been lurking for a short time but it’s obvious who the big posters are, and who seems to have real knowledge. That being said how should someone like myself decipher the difference of opinions between forums and shop advice?

So the story. I purchased a 2005 LJR, 42RLE that came with a 4.5” teraflex lift, 1” body lifted (told by the PO),and 33s. Well naturally I want 35s and my confusion starts.

As I read on here I need to up grade my gears and axles to 5.38 or 5.13 and chrome-moly axles. The shop who has +30 years experience said 4.88 and leave the OME axles. He stated that he didn’t care for gears that low in a Dana 44 and would be concerned about heat. I do drive it on the interstate to get to the trails. As for the axles. No need to put chrome-moly axles with the limitions of the axle tubes. We discussed going to dana60s but not at that price.

This is a weekend warrior Jeep. I don’t typically drive above 65 mph on the interstate and those speeds are limited to less than a hour. But I’m only 3hrs away from Moab and will would like to be able to drive the Jeep there. I wanted to go to 37s but decided against it because of the Dana 60 upgrade.

 

[Matt77]

There's some guys that really know about gears on here. Hopefully they'll chime in like @Jerry Bransford , @jjvw , @Chris .

 

[Chris]

@Jerry Bransford will agree with me, that shop is giving you bad information. First off, you shouldn't be using the OEM axles on 35s unless you never plan on taking it off-road. If you only plan on keeping it on the pavement, you'd be fine, but any off-roading and you'll destroy those axles in short order on OE axle shafts.

As for the gearing, with your setup, 4.88 would be the idea gear ratio for 33s. For 35s you could get away with 5.13, but I think the better choice will be 5.38. Jerry runs that ratio, and I am having my 5.38 gears installed (I also have a Rubicon with the 42RLE on 35s) next week.

You could go do Dana 60s, but built Dana 44 axles will handle your 35s just fine, and going to Dana 60s opens up an entirely different can of worms, big time. Now if you go to 37s, at that point you'd want to start thinking about D60s and stronger axles, yes. But with 35s, not necessary, especially considering there are guys with built Dana 35 axles wheeling on 35s.

I think his apprehension comes from the fact that he hasn't seen the success a lot of people are having with the low gears like 5.13 and 5.38. My understanding is that the 5.38 gear option for the Dana 44 axles is a more recent thing, as before that the lowest you could go was 5.13.

Either way, @Jerry Bransford will chime in with some more knowledge than I have on the subject, but going with 4.88s (especially with the horrendous .69 overdrive gear on the 42RLE) is a huge mistake. You're wasting your money at that point, I can tell you that with certainty.

 

[Rob5589]

So, I would ask the guy what personal knowledge he has regarding gears getting too hot. He will likely have none. That said, 5.38's will work fine. 4.88 is not low enough for 35's and the .69 OD that trans has.

You should strongly consider some hardened axles if running 35's and difficult trails.

 

[Powdermonkey]

I keep reading what you’re saying Chris, but I also don’t want to offend the guy. I went in there and told him I wanted 5.38 and it went from there. I don’t have mechanical experience so I need a relationship with this shop.

I have only done what I would consider easy trails. But living in western Colorado I want to do Holy Cross, Engineer Pass, Black Bear, Moab, the good shit! Im not looking to destroy the Jeep but this thing is going to see trails.

Thanks guys

 

[jjvw]

You want 5.38 with 35s and your transmission. If you are going to do Holy Cross, you ought to have cromoly axle shafts and lots of other things.

 

[Rob5589]

I keep reading what you’re saying Chris, but I also don’t want to offend the guy. I went in there and told him I wanted 5.38 and it went from there. I don’t have mechanical experience so I need a relationship with this shop.

I have only done what I would consider easy trails. But living in western Colorado I want to do Holy Cross, Engineer Pass, Black Bear, Moab, the good shit! Im not looking to destroy the Jeep but this thing is going to see trails.

Thanks guys

You are the paying customer. You should get what you want, not what he wants you to have. If he cannot deal with that, find a new shop.

 

[jjvw]

You are the paying customer. You should get what you want, not what he wants you to have. If he cannot deal with that, find a new shop.

The guy also needs to warranty his work. He doesn't need to accept job if he is unwilling to stand behind it. It doesn't matter if he's correct or not.

 

[Rob5589]

The guy also needs to warranty his work. He doesn't need to accept job if he is unwilling to stand behind it. It doesn't matter if he's correct or not.

Agreed. That is why I said find another shop if necessary.

 

[Chris]

You are the paying customer. You should get what you want, not what he wants you to have. If he cannot deal with that, find a new shop.

X2. If he won’t accommodate your needs, go elsewhere. It’s your money after all.

 

[Powdermonkey]

I really didn’t get the used car salesmen vibe from him. Don’t think I have to be concerned with him warranting his work but I guess I could be wrong.

Depending on price I may want to find another anyway. I will pay a little extra but I will confirm his pricing in Denver. I maybe ignorant to Jeeps but not completely stupid.

 

[Chris]

Another thing to consider... I talked to two very reputable gear installers (people who have been doing it all their life) before setting the appointment to have my gears installed.

Both of them suggested that for my setup (2005 Rubicon with a 42RLE transmission and 35" tires), that 5.13 or 5.38 would be the way to go. Not one of them ever mentioned 4.88.

@David Kishpaugh installs gears on Jeeps all the time, and I'm certain he would advise against 4.88s as well. That's simply the wrong gear ratio for 35" tires and that 42RLE transmission.

I'd like to know what real world experience this guy has with 5.38 gears and heat. He could be just saying that because he's never installed them into a Dana 44 before, or maybe he has a bad experience, I don't know.

All I know is that you're 100% wasting your money by putting in 4.88 gears, so if he refuses to install 5.38s and warranty it, I would just find someone else who will.

 

[mots]

I would prepare some technical information provided by the experts here and share it with him. Tell him you are spending a lot of $ and want to be sure everything is setup properly for what you need. Don't tell him the info came off the Internet because some people refuse believe anything as soon as they hear that word, regardless of the source.

You are the paying customer. You should get what you want, not what he wants you to have. If he cannot deal with that, find a new shop.

Exactly. I would be concerned about how it will be to deal with the guy if something isn't right afterwards, but HE thinks it is. How he acts now before he has your money is always important to judge. They usually aren't as nice afterwards.

 

[Andy5150]

5.38, or nothing with your set up. 4.88 will suck, 5.13 not as bad, 5.38 perfect. Keep in mind, when getting your axles re-geared, suck, not as bad, and perfect all cost the same. Find another shop if this guy won't give you what you want, or warranty his work.

 

[Powdermonkey]

Chris, I will definitely take that approach. It very well be that he just doesn’t have the experience with this setup. I was also baffled about upgrading the axles because the tubes would be the weak link. I just haven’t read that on here.

On a good note he was going to call mrblaine on the best brake setup for me. He said he has known Blaine for a long time(phone friends) so I almost if he knew Jerry as well.

I really do think the guys good, maybe just slightly behind on this particular topic.

 

[04RubiOR]

Quick question. I was in same boat as OP this past month. 2004 rubicon and I went 35’s and 4.88’s (5spd). I asked my mechanic about chromoly axles and he said

“If you install chromoly axles in Dana 44’s, you run the risk of blowing up your R&P before your axles will break, and fixing your R&P is a lot more expensive then replacing axle shafts.”

My interpretation from him was that upgrading the axles would make your R&P the week link with Dana 44’s. Thoughts?

 

[Rob5589]

I really didn’t get the used car salesmen vibe from him. Don’t think I have to be concerned with him warranting his work but I guess I could be wrong.

Depending on price I may want to find another anyway. I will pay a little extra but I will confirm his pricing in Denver. I maybe ignorant to Jeeps but not completely stupid.

Some installers just have an aversion to installing low ratio gearing, whatever the reason. Many consider 4.10 to be low and 4.56 to be ultra low. Those people would never consider a 5.XX ratio gear claiming increased heat or breakage, without actual evidence to prove their claims.

The only gear our shop had an issue with was the Richmond Gear 5.71 8" Toyota gear. The combo of guys running 36" + tires and the tiny pinion led to breakage. But that pinion is tiny. Other than that set, we did many installs of 5.57's in the Chevy 10 bolt diffs running 36/38" tires without an issue.

 

[Chris]

Gearing should be determined by the type of driving you will be doing mostly. I have the 42 RLE w/35’s and 4.88 gears because I live in Texas and need to be comfortable driving 80 plus miles an hour for long periods of time. If you live in a hilly area there’s no way I would go with a 4.88 ratio, you would simply be searching for the right gear constantly. I know a few people that run 5.38’s with the same setup as me and they Love it other than having to take the slow lane on the highway. When I swap out my axles for 60’s I’ll probably go with 5.13’s to find that happy medium. Get what’s going to suit your style of driving and the terrain you’ll be driving in. That’s my .02 cents worth :beer-toast1:

Why are they always having to take the slow lane?

 

[Chris]

Quick question. I was in same boat as OP this past month. 2004 rubicon and I went 35’s and 4.88’s (5spd). I asked my mechanic about chromoly axles and he said

“If you install chromoly axles in Dana 44’s, you run the risk of blowing up your R&P before your axles will break, and fixing your R&P is a lot more expensive then replacing axle shafts.”

My interpretation from him was that upgrading the axles would make your R&P the week link with Dana 44’s. Thoughts?

Good question actually! If you upgrade the axles to chromoly, does the ring and pinion then become the weak leak? If this is true, why is everyone doing it then?

I personally had RCV axles on my previous Rubicon and never managed to break anything. I’m probably not the best person to go off of though as my wheeling isn’t the same as the kind that @Jerry Bransford and @mrblaine are doing.

 

[jjvw]

Gearing should be determined by the type of driving you will be doing mostly. I have the 42 RLE w/35’s and 4.88 gears because I live in Texas and need to be comfortable driving 80 plus miles an hour for long periods of time. If you live in a hilly area there’s no way I would go with a 4.88 ratio, you would simply be searching for the right gear constantly. I know a few people that run 5.38’s with the same setup as me and they Love it other than having to take the slow lane on the highway. When I swap out my axles for 60’s I’ll probably go with 5.13’s to find that happy medium. Get what’s going to suit your style of driving and the terrain you’ll be driving in. That’s my .02 cents worth :beer-toast1:

What rpm would you say is optimal for 80mph?