You will be fine with Truss, balljoints, & C's. I run the same setup and have had no issues yet. Hydro is on the list of upcoming projects but not until I make her a trailer queen I like you have opted to keep the shafts as my week point so I keep spare's. I do run custom drive shafts and a rear truss as well oh and red seats

 

I agree with changing the rear shafts as well. You can stay stock spline count while upgrading to a stronger shaft (I ran 37s like this for 2 years with several wheeling trips). This way you don't have to replace the diff. If you're just doing a trip or two a year and not hitting big ledges and big rocks you "should" be fine with stock axles. You will need to go easy on it and speed will be your enemy. Don't get upset if you bend an axle shaft, expect it to happen actually. If you want to wheel it hard, get a new front axle (PR44 is fine for 37s) and upgrade the rear axle.

 

Thanks for the input. Axle shafts makes sense, at the very least having an extra set of stock on hand if not upgrading.

 

The 37" tires will make your life hell with the stock drag link (bar from pitman to passenger knuckle) as it constantly bends and your carrying a 15mm socket and ratchet with you so you can re-center the steering wheel from just on road use!

37" tires will make bending you stock tie rod (what we used to call the center link, it crosses from knuckle to knuckle) very easy. Luckily that drag link is weaker yet so it acts as a fuse and bends just from hitting a decent pothole! Once you get that drag link secured, you'll really want a Yeti or Fusion tie rod.

The lift you have may have not came with a forged or chromoly track bar (frame on drivers side to axle on passenger side) and this thing (if stock) is flexy/bendy and makes the entire vehicle handling feel vague and odd. Secure that with a forged or chromoly shaft and you tighten up that front axle, you will feel this tighten up!

Your rear shafts will easily bend at the flange to shaft interface and also at the spline to shaft interface with a 37" tire. Going to a Ten Factory, RCV or G2 Placer Gold shaft will prevent this unless you go into hooligan mode.

You'll get away with the stock steering on the street, but the Redneck Ram or similar will take a lot of the stress from the failure prone sector shaft and gear box. I did both the Redneck Ram as well as the Synergy sector shaft/track bar brace that attaches at the drivers side frame.

I went into the 37" tire change by trying to research the known weak links, and patching all of the known issues that I reasonably could before mounting the tires. I did a ton of reading and making notes, then I put a plan on paper and started ordering parts. But now I have a JK on 37" tires that I am not afraid of. The only thing I cheaped out on and am not happy with is the Ruff Stuff DIY tie rod. I wouldn't really recommend it unless your out of money (I was!) and need to get it secured for the year while you plan your real tie rod for next year (I am). I like the Yeti, I saw one on another fellows JKUR and it looked really good with plenty of offset to get around the Dynatrack diff cover. I had to be creative to make the Ruff Stuff work by putting 20° bends in the ends to clear the diff cover. Now, it can not be adjusted on the vehicle. It's a pain in the butt, and my ram could pretzel it if I put the drivers tire against a telephone pole and push the drivers sidewall into the pole as if trying to push the Jeep sideways. So even after spending $12,000 this spring doing my transition to 37" tires, there are some things that I am not happy with, and next spring I will tie up those things. For this year, my wife has had enough and I am shut off from the money flow!

 

Nobody has yet to mention gears which will help take stress off the driveling and enable you to drive slower off road. At least you have the rubi case. Rear shafts would be a good upgrade but a full float ton on the back would be ideal. Even with upgraded shafts the semi float axle is not a good match for a heavy vehicle. Up front I would not waste the money on the "truss" as it adds little strength vs what it costs. Its really not a proper truss but many people have jumped on this bus and think they are getting a big upgrade.

I can't really give you a good answer of the front axle as the options out there are poor. Technically a dana 44 should be fine for the front. Unfortionaly the JK has a poorly designed dana 44 (well it was designed for 32" tires, cheap price, and being light in weight). While they increased the size on the ring and pinion (good thing), they cheapened the axle by using light weight housing tubes, inner C's, cheap small ball joints, and cheap unit bearings. This is barely good enough for stock tires let alone jumping up to 37's and your choices to upgrade are expensive or take a lot of time and knowledge in axle building.

Going to a pro rock 44 housing typically runs $5200+ and retains the weak unit bearings, small brakes, and small ball joints. You can do the spyntec conversion for another $1300 and a big brake kit $775. Now you are in the fully built Dana 60 range and have a decent reliable axle and if you were smart you ordered a custom pro rock 44 in a 68" WMS to give you the extra clearance for the big tires and take some of the stress off the ball joints. Most people order the factory width housing because they don't take 12 weeks to get.

You could buy a new dana 60 with bigger brakes and ball joints with lock out hubs in the $7-8k range. You also have ford 9" options. Again look at at least a 68" WMS

You can buy a remanufactured 60 axle from Fusion in the $3-4k range.

You can look for a deal on a junkyard axle and build one your self but will find it hard pressed to do it for what Fusion is offering.

The drawbacks from doing a 60 is extra weight, less clearance, and you are going to buy new wheels and have the driveshaft rebuilt. $$$$

When I went to 37's I broke rear axle shafts, driveshafts (running 4.10 gears), punctured tires from tight clearances, but never had an issue with the front rubi axle. At the time I sleeved it and did gussets and ended up going to 5.13 gears. Looking back I doubt the sleeves did a whole lot but at the time thats what was the "big thing" to strengthen the axle housing.

I am not telling you to go out and buy new axles, you may need them (depends on how you drive) or you may not but you should expect to brake stuff and not be surprised if it happens on components that were designed for 32" tires.

I don't know what your wheel back spacing is and I am not going to look it up but I would shoot for a 3"-3.5" back spacing for 37x12.5" tires so you may need wheel adapters, and I would install 5.13 gears and rear axle shafts. Everything else you have should be fine. You really don't need hydro assist with 37'x12.5" tires. If you are bending steering links upgrade them. As far as a drag link flip at the 3" lift level, I would say no unless you are prepared to notch the frame for up travel.

 

If you actually wheel you will certainly need hydro, especially if you're running below 12 lbs Offroad. Even on road with 37s with 24 psi turning into rough asphalt parking spots sucks I'm not sure how you say the trusses out aren't worth anything as they most certainly tie each tube to the pumpkin and to each other. I chose also to weld the tubes to the pumpkin. The trusses out aren't bad options but you can always build your own out of 1/4 or boxed in 3/16. Pretty easy.

 

A proper truss would be solid from C to C and go over and around the center section with some boxing, not just a 1/4" or 3/8? bar. The stronger ones will tie into the center section with a diff cover that is bolted to the truss, not welded to the center section. We already had the discussion about your welding the center section with a mig and mild steel welding wire. I am not sure how you think you have a good strong weld when it was not done with the correct process and welding wire. All you have done is put filler in a gap and over time it will crack out. The only thing the Artec trusses is the individual tube, not the whole axle and the weak points are still deflection at the center section. Artec only only states the axle is stronger but shows not data or testing to confirm what is stronger or by how much. If you were to put an axle in a press supported at he C and pressed the center section I doubt the truss would keep the axle from bending at the center section and I would bet it would put extra force on the bottom of the casting causing a crack in the housing itself vs bending the tube.

Many people wheel without hydraulic assist on 37x12.5" tires even when aired down below 12 psi. Would it help off road, yes, but do you have to have it?, No. The OP does not have bead locks and really does not appear to wheel hard in the rocks and rarely sees rocks in his off road trips. Assist would be nice but not a must have. The OP will decide that since he is planning on the 37's first and adding the assist down the line.

 

Ten words