So I've searched the miracle of the internet high and low over the 5.13 vs 5.38 debate.
I have an JKU X so only a D-30 in the front. I've read all the articles and forum posts across the JK forums about how the pinion is smaller with the 5.38s and is prone to breaking.
Has anyone ever ACTUALLY busted the pinion, and if so is it attributed to being so small and potentially weaker inside the D-30?
I do mostly trails, and it's my DD (I deploy alot) so I'm not taking on the Rubicon anytime soon nor am I looking to upgrade to 37s. Just all that I've read from those with the 5.38s love them and I don't want to wonder what if I had only gotten 5.38s instead of 5.13s.
The shop quoted me the same price for both 5.13 and 5.38s so I'm at a decision point now.
I had Dana 30 cj7 4.56 and the contact point between the teeth on the ring and the pinion was so small I busted 1.75 teeth off coming down from a wheel stand. The pinion was fine, the ring gear busted the teeth.
Most reputable gear manufacturers will not make 5.38's for the D30JK. I have held a 3.73 and a 4.88 pinion in my hand, and I would hate to see how small the 5.13's are - let alone a 5.38 for a D30JK. I'd say you can pick your teeth with a 5.38 pinion, haha!
This is why they make bigger axles - larger R&P sizes to handle bigger tires. I wouldn't do it, personally.
How big of tires do you plan on swinging on that D30JK, anyhow? Cause it sounds like there are going to be more issues than just a small pinion size...
I've had YUKON 5.38s in my Rubi Dana 44s, for over two years and in my first breakin run (20miles)--my rear diff reached 300°F and thats without a great difference in pinion size, ie (D44-4.10/D44-5.38)--so
Thats one of the reasons that 5.38 gears are SCARCE for the dana 30, strength notwithstanding--
Well, I have 5.38's on 37's. No issues at all. Already been through a front driveshaft (twisted it in half like a candy wrapper), and snapped the left rear axle shaft, but no problems with the 5.38's pinion.
BTW, lead foot + supercharger while playing the rocks was the cause of those mishaps. After 3 hours of winching off the trail (the axle shaft and driveshaft happened within minutes of each other on the same trail), I learned that technique is more important than brute force.
He was asking about 5.38 gears and the pinion, not D44 vs D30.
The only difference between a D30 and D44 is the differential housing size, no strength differences. So, my point is valid by speaking of 5.38's in a D44.
He was asking about 5.38 gears and the pinion, not D44 vs D30. The only difference between a D30 and D44 is the differential housing size, no strength differences. So, my point is valid by speaking of 5.38's in a D44.
The ring and pinion on the Dana 44 is significantly larger, as well the rubicon 44s both feature larger main axle shafts and higher spline counts.
The only thing the jk44 and the jk30 share are tube size, inner and outer knuckles, outer shafts, ball joints bearings and brakes. Everything else is different.
2010 Magnetic Toyota 4Runner Trail Teams