5.38s with 37s

[TheRealGinjaNinja]

Yeah, I was thinking that too as I compared. A couple of them looked identical. Also, my ridge grapplers are about halfway through their life. They were put on around 2K miles.

This has definitely given me some food for thought. I might just buy the Mopar crate D44 with 5.13’s and call it a day. The front axle was the worst. Had a shop here in Denver correct them as best they could. The front carrier literally fell out after taking the bearing cap bolts off. They didn’t even need to spread the housing.

Yea my tires are brand new basically. Sorry to hear about your shoddy axle work though that’s crazy!

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[hjdca]

Those look good. I'm using the dana gears and will probably end up going with the dana Advantek covers too. They have the Fins that should help with cooling, and once my final ring gear ships I should be getting a $150 gift card to Northridge from their black Friday deal.

I've never felt like you could put too much fluid in the diff as long as it has some room to move around, I'm planning on filling it up.

Thanks.
Note: adding additional fluid can contribute to extra pressure causing seal leakage…. Also foaming could also be a consideration. It’s best to follow the recommendations of the diff cover manufacturer. For example, metalcloak recommends the stock amount even though their fill hole is higher and the stock fluid amount does not reach the fill hole.
Note2: I have also read that appropriate liquid gasket instead of the jeep reusable gasket adds additional strength to the pumpkin housing with modular iron covers.

 

[1550jrit]

I’m curious what the oil pressure is at 80mph with the 5.38’s? I’m also running a Mojave on 37’s with the 2” AEV lift. I’ve been waiting on my 5.13’s for 3 months but Northridge does have Dana 5.38’s in stock. I run 75-80 mph regularly but don’t necessarily want to be in the second stage of the oil pump the entire time when cruising at that speed. Any feedback is appreciated!

 

[1550jrit]

Well, I did some digging and answered my own question. Second stage of of the oil pump doesn't kick on until 3000 rpm's, which I confirmed today on my truck. Being that I will be at 2650 at 80mph with the 5.38's, I went ahead and pulled the trigger on them. My shop got them ordered (Dana Spicer) from Northridge and we will be doing the install next week. This thread was super beneficial with pushing me in that direction. I seriously don't know what the major hold up is with these Dana gears?! Regardless, I think I will be happier with the 5.38's with my style of driving. Thanks again.

 

[Northridge4x4]

I seriously don't know what the major hold up is with these Dana gears?!

Dana builds everything in runs. So we all have to wait until the next run of any particular part is done. Then they ship them out to the distibutors who ship them from there. Unfortunately, Dana builds so many different parts, they'll be out before they get back around to the next scheduled run.

 

[1550jrit]

Dana builds everything in runs. So we all have to wait until the next run of any particular part is done. Then they ship them out to the distibutors who ship them from there. Unfortunately, Dana builds so many different parts, they'll be out before they get back around to the next scheduled run.

Thanks for the reply Northridge! Torc Motorsports in Omaha will be doing the install and we’re the ones who snagged the 5.38’s from you. Looking forward to the gears!

 

[1550jrit]

I just picked up my Mojave from Torc Motorsports in Omaha, NE following a re-gear to Dana Spicer 5.38's. Thanks to Carlos and his crew for fantastic install and they also completed all of the break-in heat cycles. I paid approximately $2350 for the gears with install, which included installing two Dana Advantek nodular iron diff covers that I had already purchased from Northridge.

First impression is that 5.38's are definitely not too deep for a Gladiator on 37's. I've lived in Nebraska all my life and always regarded it as a pretty flat place. However, in reality it's a decently hilly place around the Omaha metro area. My normal drive on our expressway, which traffic generally runs 75-80 mph, is hilly and fast. My truck would previously hunt between 5-6 gear in order to keep up with the speeds and terrain. I never saw 8th gear with my 4.10's. I'm happy to report that the truck now sticks to 8th gear for the most part and will only downshift to 7th when it needs to.

The truck shifts smooth with very little difference in transmission feel from before. I can tell that there's a ton more torque but I'm still in the 1000 mile break-in period so I did my best to limit my throttle to 50% or less. I was really shocked to see that even on city streets where I was driving 35-45 mph, the transmission got up to 8th gear rather quickly and held it there for the most part.

I had the opportunity to run a 75 mile round trip errand for my wife, which I saw as an opportunity to earn good husband points and also give the new gears a spin. The trip was mainly interstate and highway and I did my best to maintain the speed limit the entire way. The truck now has no problem maintaining 8th gear up to 80 mph and will hold the gear up a pretty steep incline. I'm positive that 5.13's would have been shifting a little more between 7th and 8th, which is not a big deal, but I'm happier with the 5.38's ability to hold 8th more frequently. As the OP reported, my truck is holding 80mph at approximately 2750ish rpm's and is in the first stage pf the oil pump.

Transmission and engine temps were all normal. What really changed was my gas mileage. I filled up and reset before making he trip. My truck was previously averaging about 11.5 mpg with winter fuel. This round trip I averaged 15.1 mpg, but also concede I was driving very easy on the throttle and staying right around the posted limit. I'm sure my mpg's will drop some once I'm driving like my usual self, but I'm encouraged that I will still see an increase in gas mileage.

In conclusion, I'm super happy that I wound up with 5.38's. If it wasn't for the 5.13 backorder I never would have considered making the jump to 5.38's. Thanks again to Torc Motorsports for the fantastic install and Northridge for the parts. I'll post another update once I'm outside of the break-in period.

 

[Panthers65]

Dana builds everything in runs. So we all have to wait until the next run of any particular part is done. Then they ship them out to the distibutors who ship them from there. Unfortunately, Dana builds so many different parts, they'll be out before they get back around to the next scheduled run.

Hope I'm on that list, I've been waiting on my 5.13's I ordered on yalls black Friday deal...

 

[Northridge4x4]

Hope I'm on that list, I've been waiting on my 5.13's I ordered on yalls black Friday deal...

I'll get someone to check for you. Just PM'd you.

 

[TheRealGinjaNinja]

I just picked up my Mojave from Torc Motorsports in Omaha, NE following a re-gear to Dana Spicer 5.38's. Thanks to Carlos and his crew for fantastic install and they also completed all of the break-in heat cycles. I paid approximately $2350 for the gears with install, which included installing two Dana Advantek nodular iron diff covers that I had already purchased from Northridge.

First impression is that 5.38's are definitely not too deep for a Gladiator on 37's. I've lived in Nebraska all my life and always regarded it as a pretty flat place. However, in reality it's a decently hilly place around the Omaha metro area. My normal drive on our expressway, which traffic generally runs 75-80 mph, is hilly and fast. My truck would previously hunt between 5-6 gear in order to keep up with the speeds and terrain. I never saw 8th gear with my 4.10's. I'm happy to report that the truck now sticks to 8th gear for the most part and will only downshift to 7th when it needs to.

The truck shifts smooth with very little difference in transmission feel from before. I can tell that there's a ton more torque but I'm still in the 1000 mile break-in period so I did my best to limit my throttle to 50% or less. I was really shocked to see that even on city streets where I was driving 35-45 mph, the transmission got up to 8th gear rather quickly and held it there for the most part.

I had the opportunity to run a 75 mile round trip errand for my wife, which I saw as an opportunity to earn good husband points and also give the new gears a spin. The trip was mainly interstate and highway and I did my best to maintain the speed limit the entire way. The truck now has no problem maintaining 8th gear up to 80 mph and will hold the gear up a pretty steep incline. I'm positive that 5.13's would have been shifting a little more between 7th and 8th, which is not a big deal, but I'm happier with the 5.38's ability to hold 8th more frequently. As the OP reported, my truck is holding 80mph at approximately 2750ish rpm's and is in the first stage pf the oil pump.

Transmission and engine temps were all normal. What really changed was my gas mileage. I filled up and reset before making he trip. My truck was previously averaging about 11.5 mpg with winter fuel. This round trip I averaged 15.1 mpg, but also concede I was driving very easy on the throttle and staying right around the posted limit. I'm sure my mpg's will drop some once I'm driving like my usual self, but I'm encouraged that I will still see an increase in gas mileage.

In conclusion, I'm super happy that I wound up with 5.38's. If it wasn't for the 5.13 backorder I never would have considered making the jump to 5.38's. Thanks again to Torc Motorsports for the fantastic install and Northridge for the parts. I'll post another update once I'm outside of the break-in period.

Awesome and congrats on the great price for the install!! Thanks for sharing your write up! Apologies for my slow reply, I Have no idea why I never saw an alert for this thread the past two weeks.

I will admit my fuel mileage has been lower the last couple of tanks partially because I have floored it maybe a few times lol. Still really happy with mine.

I forget if I called it out previously but another thing I noticed is how the transmission downshifts while decelerating a lot more aggressively than before. The behavior is almost as if the Jeep had a tow haul mode!

Cheers

 

[1550jrit]

I am 400 miles into my break-in period and absolutely loving the 5.38’s! The truck is so much more lively and drives fantastic. I did experience some of the aggressive downshifting at first. It was much more apparent when turning corners, the transmission would downshift and it would feel like a manual when you downshift too far. That seems to have smoothed out as the transmission has learned.

I’ve never driven a gladiator with 5.13’s and I’m sure they would have driven great coming from 4.10’s. That being said, I think 5.38’s are perfect for my driving style and the hilly terrain around Omaha. I’m super happy I held out for the Dana Spicer gears as they have been quiet and smooth from the start. My plan is to hit about 50 miles of easy gravel roads this weekend so I can give the front gears a workout. So glad I came across this thread, never would have considered this setup otherwise.

 

[1550jrit]

Update.

I am currently 1500 miles out from my re-gear and the truck runs great with 5.38’s. My 1000 mile differential oil exchange and inspection was perfect, barely any metal shavings in the break-in fluid. I think that waiting on the Dana Spicer gears was the correct call.

5.38’s on 37’s are very nice as a daily driver. I hardly notice any shifting differences from the factory 4.10’s, other than it tends to quickly get into the OD gears and stay there. Torque is fantastic now that I can give it 100% throttle again. It pulls super hard off the line almost as if you took a stock truck and tuned it. I can’s even tell that I’m on 37’s anymore.

I’d say between the wind and and hills around my area, I’m happier to have the deeper gears. I’d eventually like to do a small overlanding Trailer some day so the extra torque will come in handy there. Gas mileage has settled down to about a 1-2 mpg improvement, which is still only getting me about a 13.5 mpg average (winter blend at the moment), but better than 11.5 mpg.

5.13 vs 5.38, I’m saying you’ll be happy either way. However, don’t shy away from 5.38’s because you think they’ll be too deep.

 

[DustyGladiator]

Trending positive…the attached pic shows my recent fill ups. My lifetime average is 13 mpg.

I only had one fill up since regearing. I admit it could be a bit skewed by slower overall speeds during break in but I also had a lot of idle time due to heavy snow/ice and extremely low overall temps which hurts it.

What app is this?

 

[Escape.idiocracy]

Update.

I am currently 1500 miles out from my re-gear and the truck runs great with 5.38’s. My 1000 mile differential oil exchange and inspection was perfect, barely any metal shavings in the break-in fluid. I think that waiting on the Dana Spicer gears was the correct call.

5.38’s on 37’s are very nice as a daily driver. I hardly notice any shifting differences from the factory 4.10’s, other than it tends to quickly get into the OD gears and stay there. Torque is fantastic now that I can give it 100% throttle again. It pulls super hard off the line almost as if you took a stock truck and tuned it. I can’s even tell that I’m on 37’s anymore.

I’d say between the wind and and hills around my area, I’m happier to have the deeper gears. I’d eventually like to do a small overlanding Trailer some day so the extra torque will come in handy there. Gas mileage has settled down to about a 1-2 mpg improvement, which is still only getting me about a 13.5 mpg average (winter blend at the moment), but better than 11.5 mpg.

5.13 vs 5.38, I’m saying you’ll be happy either way. However, don’t shy away from 5.38’s because you think they’ll be too deep.

Do you have any long highway runs planned?? Sustained highway at 70-80mph. This is where the most heat is going to be, and effects shown.

I’ll be joining with ours and 5.13’s motive gear and Dana covers. Plan is to run a gl5 natural gear oil this go around. Guess we will see. ??‍???

 

[1550jrit]

Do you have any long highway runs planned?? Sustained highway at 70-80mph. This is where the most heat is going to be, and effects shown.

I’ll be joining with ours and 5.13’s motive gear and Dana covers. Plan is to run a gl5 natural gear oil this go around. Guess we will see. ??‍???

So I’ve actually made a few sustained runs at 80mph, the most recent one being 3 hours down and 3 hours back in one day. I did make it a point to feel my rear diff cover when I got home and although it was moderately hot, I could hold my hand to it without feeling like I was going to burn anything. My Dana diff covers do have the cooling fins, which I believe work as intended. I’ve had my gears now for 6k miles with zero issues. During the last trip my oil, tranny, and coolant were all in the normal ranges 195-205 degrees and the truck ran great. It was 95 degrees outside, I had my cruise set to 81 mph and had my AC going the entire time. I couldn’t be happier with my setup. I am planning a longer trip to Ouray in a few weeks and that will be a longer drive, 13 hours straight. If I can track down one of those digital infrared thermometers I’ll see if I can get some actual readings of my differentials throughout the trip. I hope this helps!

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