Built Dana 30 with 5.13 gears vs Built Dana 44 with 5.38 gears

Jerry Bransford said:
Probably but I STRONGLY (!!!) suggest you not buy the gears, locker, etc. on your own trying to save a few bucks with the intention of giving the parts to the installing shop. Have the shop provide all parts. Period. It may cost a tad more but then the installing shop's warranty will cover everything, all parts and labor, instead of just their labor.

If you think the gear and locker manufacturer provides a warranty that's true BUT if something fails, the usual cause of the failure of gears and/or lockers is due to the installer screwing something up. And if that happens, the installing shop will blame the parts you provided and claim they installed everything perfectly. The gear/locker dealer will blame the installation process, which is indeed the usual source of post-installation problems.

By having the shop provide everything they can't point their fingers at anyone but themselves. You can tell them you want an ARB locker and Revolution Gear gears but have them source them themselves. That can eliminate a whole lot of grief, problems, and finger-pointing.
Click to expand...
Okay yes this makes total sense, i called Globex performance NJ and they said that 4.88 is the most they would put in a dana30, i told him my specs, and he said 5.13 would be screaming on the highway. What are your thoughts?
 
I just filled up the Jeep.
118.7 miles on the Freeway at 65-70 mph
Tires were at 29 PSI when I filled them, at 26.5 when I check them at the gas station
7.517 gallons of fuel (letting the auto-stop click off 3 times)
15.8 MPG

That is higher than I expected. The drive was from about -200 feet of elevation (Salton Sea) to 800 Feet back home.

Here is a quick list of the mileages on the way from CO to CA - 16.8, 14.5, 17.8, 16.8, 14.2, 12.3, 12.6 and 14.6
 
  • Like
Reactions: Tioga river Rat
connorwfrench said:
Okay yes this makes total sense, i called Globex performance NJ and they said that 4.88 is the most they would put in a dana30, i told him my specs, and he said 5.13 would be screaming on the highway. What are your thoughts?
Click to expand...
Two thoughts... 1) He doesn't know about your 42RLE automatic transmission and how it drops the highway rpms by 31% when it shifts into 4th/Overdrive. 2) He doesn't know WTF he's taking about.

Once again, many of us are running 5.38 gears with 35"tires and the 42RLE transmission. I am too. My rpms at 70 mph are roughly 2600. No higher than they should be for 35's. 2600 is barely adequate for 35's I'd rather have another 150 or so. Your rpms with 5.13s would be even slightly lower than that.

Would I run 5.38 gears for 35's with my previous 32RH 3-speed automatic or 5-speed manual transmissions? Nope. That's what your Globex guy is basing his misinformed opinion on.

I know I already mentioned my 2600 rpms at 70 mph with my 5.38 gears and 42RLE at least a couple times above,right? Does it still sound like Globex guy knows what he is talking about? I hope you understand now why he does not.
 
  • Haha
Reactions: Irun
connorwfrench said:
Okay yes this makes total sense, i called Globex performance NJ and they said that 4.88 is the most they would put in a dana30, i told him my specs, and he said 5.13 would be screaming on the highway. What are your thoughts?
Click to expand...
Find another shop that will do the 5.13 if they won't. The ring and pinion is generally not the weak link in the differential, even with 5.13 gears. Generally, you'll blow up the carrier, snap an axle shaft, or pop a u-joint before the ring and pinion give up the ghost.

4.88 will be very inadequate unless you do a manual transmission swap (not recommended).
 
  • Like
Reactions: Jerry Bransford
Steel City 06 said:
4.88 will be very inadequate unless you do a manual transmission swap (not recommended).
Click to expand...
I am clearly missing something.
I have the Automatic with 4.88 gearing on 35" tires (ok technically 34.4")
I can cruise down the freeway at 70 MPH pushing 2250 RPM and getting 15.8 MPG
It performs very well offroad, I haven't gone anywhere crazy yet, but I have no issues on the trail with power.

The Jeep is not a speed demon by any means, my 2006 Silverado with the LBZ will blow it away.
Why would I want to run higher RPM on the Freeway? Passing someone at very high speed?
 
  • Like
Reactions: Tioga river Rat
Nightmare9 said:
I am clearly missing something.
I have the Automatic with 4.88 gearing on 35" tires (ok technically 34.4")
I can cruise down the freeway at 70 MPH pushing 2250 RPM and getting 15.8 MPG
It performs very well offroad, I haven't gone anywhere crazy yet, but I have no issues on the trail with power.

The Jeep is not a speed demon by any means, my 2006 Silverado with the LBZ will blow it away.
Why would I want to run higher RPM on the Freeway? Passing someone at very high speed?
Click to expand...
Because your engine is lugging at those rpms. Really. I bought my present TJ with that combination and knew from the beginning it was lugging. I was finally able to regear from 4.88 to 5.38 and EVERYTHING got better. It performed better on the highway with the extra rpms and even my highway mpg went up 2.6 mpg to 14.6 mpg.

Do lighter cars with smaller car size tires run fine at significantly lower rpms? Of course, my daily driver car does too.

But whether you can tell when your 4.0 is lugging or not, it is much of the time. As said above, my engine ran so much better after regearing from 4.88 to 5.38 that my mpg went up 20%. That's pretty good proof how inefficiently it was running with 4.88.
 
Chris said:
So I assume your Ford is also hunting for OD? I think that's my biggest annoyance with the 42RLE is that it wants to be in OD all the time, so unless you switch it off anytime you start the vehicle (which admittedly does make it so much better to drive), it's constantly shifting back-and-forth between 3rd and 4th gears, and doing it much to soon.

I finally got in the habit of just turning off OD anytime I started the vehicle. Once in this habit, it didn't bother me anymore. Still, it's a hard habit for some to make.
Click to expand...

It is a typical problem for the AOD, but tightening the TV cable helped mine quite a bit. Ford typically set the TV cables at a neutral position at idle (minimum TV pressure) for better mileage and seamless shifts. I tightened mine so that the TV cable is at full pull at full throttle (maximum TV pressure - just like they set them on the Mustang GT), which pre-loads the TV cable to give more pressure at every throttle position. The result is firmer, more positive shifts across the board and the transmission doesn't shift into overdrive until about 45 MPH. It is actually better for the transmission when the TV cable is set this way, since it reduces the time the transmission is in two gears at once.

But the AOD isn't computer-controlled, and the engine is carbureted, so I don't know if doing that will help on the 42RLE or not.
 
  • Like
Reactions: Chris
TJRick said:
It is a typical problem for the AOD, but tightening the TV cable helped mine quite a bit. Ford typically set the TV cables at a neutral position at idle (minimum TV pressure) for better mileage and seamless shifts. I tightened mine so that the TV cable is at full pull at full throttle (maximum TV pressure - 6 like they set them on the Mustan
Click to expand...
There is no TV cable on a 42RLE, it is purely computer controlled.
 
Shows how shops are typically a bit outdated. My Jeep has been in Globex before. They are a very nice shop that does nothing but Jeeps from what I remember. They build some cool stuff. Even the shop that did my frame swap would recommend 4.88's and JKS long arms if you asked. That was all the rage when they were doing a whole lot of TJ's years ago and the owner runs that combo in his personal LJ. It is the main reason I like forums more than listening to shops.
 
  • Like
Reactions: tworley, Irun and connorwfrench
Jerry Bransford said:
Two thoughts... 1) He doesn't know about your 42RLE automatic transmission and how it drops the highway rpms by 31% when it shifts into 4th/Overdrive. 2) He doesn't know WTF he's taking about.

Once again, many of us are running 5.38 gears with 35"tires and the 42RLE transmission. I am too. My rpms at 70 mph are roughly 2600. No higher than they should be for 35's. 2600 is barely adequate for 35's I'd rather have another 150 or so. Your rpms with 5.13s would be even slightly lower than that.

Would I run 5.38 gears for 35's with my previous 32RH 3-speed automatic or 5-speed manual transmissions? Nope. That's what your Globex guy is basing his misinformed opinion on.

I know I already mentioned my 2600 rpms at 70 mph with my 5.38 gears and 42RLE at least a couple times above,right? Does it still sound like Globex guy knows what he is talking about? I hope you understand now why he does not.
Click to expand...
Yes I’m planning on finding another shop to do everything, anybody know any good shops in the tri-state/Philadelphia area? He was bashing you guys when i was asking him to do 5.13 and i kinda just hung up on him 😂
 
connorwfrench said:
Okay yes this makes total sense, i called Globex performance NJ and they said that 4.88 is the most they would put in a dana30, i told him my specs, and he said 5.13 would be screaming on the highway. What are your thoughts?
Click to expand...

I THOUGHT Globex was a reputable shop but if they really told you that I wouldn't go near them.
 
Lou said:
I THOUGHT Globex was a reputable shop but if they really told you that I wouldn't go near them.
Click to expand...
That’s what i was told as well! And on the phone i was explaining how all these guys on this forum have reccomended 5.13/5.38 and i asked for a quote on 5.13 and he said “those forum guys” have no clue what they’re talking about, and he wouldn’t go passed 4.88, very irritating
 
If you want to drive around with OD off all the time then 4.56 or 4.88 will work. If you want to use OD you really need at least 5.38 for 35's.
 
  • Like
Reactions: Irun
Main line overland is near you but I'm not sure if they do gears. There is a place in Horsham called Busted Knuckle off-road that does some cool stuff from what I remember. Keep in my the only experience I've had with them is accidently ending up in their parking lot a few months back.

Globex is a reputable shop and does good work. I would be very surprised if any shop you call would recommend 5.13. 4.88 was the standard just a few years ago for the 42RLE and 35's. Most shops don't deal with TJ's much anymore so they are still reciting that 4.88. You just have to find a shop that is willing to put the parts that you want on the Jeep.
 
Last edited:
  • Like
Reactions: Jerry Bransford
jodomcfrodo said:
Main line overland is near you but I'm not sure if they do gears. There is a place in Horsham called Busted Knuckle off-road that does some cool stuff from what I remember. Keep in my the only experience I've had with them is accidently ending up in their parking lot a few months back.

Globex is a reputable shop and does good work. I would be very surprised if any shop you call would recommend 5.13. 4.88 was the standard just a few years ago for the 42RLE and 35's. Most shops don't deal with TJ's much anymore so they are still reciting that 4.88. You just have to find a shop that is willing to put the parts that you want on the Jeep.
Click to expand...
Ohh yes that makes sense, why were 4.88s the standard before? People just didn’t use overdrive?
 
connorwfrench said:
Yes I’m planning on finding another shop to do everything, anybody know any good shops in the tri-state/Philadelphia area? He was bashing you guys when i was asking him to do 5.13 and i kinda just hung up on him 😂
Click to expand...

Good for you. Tell them to 💋
6h8C6ygTdR2jyyUxkALwsc.jpg



And move on to a shop that will really help!
 
  • Like
Reactions: Jerry Bransford and connorwfrench
Top Bottom
Back