DKJEEP

Ok so I stumbled on some info and have done about 3 hrs of reading this evening and what I have found out scares the shit out of me. So here is what is going on and I am looking for the good bad and ugly on this potential issue.

I currently have all of these products literally sitting in the garage waiting to be installed during the X-mas break.

4" OME lift
new front and rear double cardan shafts that have replacement yokes for both axles and t-case.
5.13 gears
I have a set of used 35" tires that I am going to install with the lift but am going to 37 when they are worn out.

Just FYI but right now the jeep a 08 2dr. sahara auto has 33" tires, 4.88 gears, and a 2.5" budget boost. I have had no issues with this setup for at least 60k miles besides the front shaft boot giving it up about 10k ago.

I am reading that with the parts that I want to install that I am basically going to grenade the t-case at any moment by going anywhere form 60-80mph for any prolonged period of time. The ome lift comes with some caster correction for both front and rear axles and from what I am reading it gets it pretty close to a very good pinion angle. The 35's with the 5.13 gears will turn slightly less RPM at 70mph than the 4.88's do with the 33's but the drive angle is not as steep with the budget boost I have right now.

What is the general consensus on this????

ronjenx

With a double cardan at the t-case, the pinion and single cardan at the axle has to be nearly straight, (in line), with the drive shaft.
Being more than a couple degrees from straight will cause the double cardan at the t-case to vibrate.
A few years ago, the front of the t-case on quite a few JKs exploded from this vibration. In an effort to have a compromise between pinion angle and caster, it was impossible to get the pinion and single cardan close enough to being in line with the drive shaft.

DKJEEP

I did notice that those threads about the issue were at least a couple of years old. I haven't seen any of those type of threads lately but I have not been on here as much the last couple of years. So what exactly are you saying? That I will be driving a bomb?

ronjenx

I figure people learned from the explosion posts, and did what they had to prevent it, or when they do explode, they know why and don't need to post about it.

Driving a bomb? Not if you get the front pinion angle close to zero with the drive shaft. If you can't, you'll have to drive slower than highway speed. Highway speed is where the explosions occurred.

I keep referring to the front because it's easy to get the good angle on the rear.

Canvas

I have been running 5.13 gears in my stock axles and have not had any issue with my TCase. It all comes down to performing the maintenance when you need too. If you do not check or replace the fluid yeah that could happen. Now if you are out on the trail and heavy on the skinny pedal I could see how this could happen.

I think SM Rubi has been running 1 tons with a stock Rubi TCase for quite some time. I have also heard of guys running Hemi's with a sport and Rubi TCase until they had the money to upgrade to an Atlas.

R/
Will

Wrangeler X

I have been running 35,s 37,s,4.88 and 5.13 gears 2.5" and 3.5" lift with stock arms and now with adjustable RK lower with varying degrees of castor for along time. 50000 miles worth. I have a coast front driveshaft. Right now I'm at 6+castor with no issue although I'll be getting back to 4.5-5 this weekend although surprisingly I don't have any vibrations by I don't like how it handles. Long story how I got to that castor, it was unintentional.

I would say if your vibrating the transfer case yoke then you should adjust castor as needed to reduce or eliminate it. Otherwise change your fluid regularly and inspect u joints and such regularly and replace when needed.

I did have my DS rebuilt recently. The double cards in u joints were shot.

I think most people with lifted jeeps and aftermarket DS. Are not running 0 castor. The handling would be horrendouse. If this concern was valid then they wouldn't be doing it.

Northridge 4x4

sea bass

So you're going from 4.88s to 5.13s? Doesn't hardly seem like enough of a jump to make it worth it. You're only talking like a 5% difference.

ShutterBug

I could see the extra ratio being useful on the 3.8L with the 37s. If you're doing the work yourself, and there's not a huge labor cost, then it makes a little sense.

Biginboca

OP:

Keep your castor around 4 to 4.5 degrees and you will be fine at first. Then be religious about maintaining your driveshaft ujoints (grease every 3-5k miles) and you will be good long term.

Make absolutely certain you grease the centering ball of the double cardan joint. Lack of grease here has been what most of the detonations were traced back to. Any "quicky lube" type places will not grease this critical joint. The only way to grease it is to drop the driveshaft so you can get a needle inside there. DIY maintenance is the only proven solution here.

I have 5:13 and a DC front driveshaft on 37's for almost 40k miles driven at 80-85 mph daily. Don't neglect these points above and you will be fine!

DKJEEP

This is more than I bargained for. First it was the lift when I found out that you need new DS when you get in that 3.5"+ range. I knew that before I ordered the lift but still it just about an absolute requirement to get them. Now this....... SOOOOOOOOOO. I have had greasable joints in previous vehicles and I realized it was a pain or just something else to take care of to always be greasing the joints. Doing it at oil change really dosent work for me as I have always run full synthetic with a premium filter and I usually go 8-9k miles between oil changes. This is probably too long to wait to grease the joints. I went back to the page where I bought the 1310 shafts and I remembered that I picked these because they have "NON GREASABLE SPICER U JOINTS" These are the white seal spicer joints. Also "NON GREASABLE CV" If I understand this right the part that you guys say needs to be greased with a needle is not serviceable on this shaft and is a sealed unit like the u joints. In my infinite wisdom I was thinking this would cut down on maintenance.

Back to the pinion angle. It sounds like this issue is all but eliminated if you get the pinion and the drive shaft in as close to a straight line as possible. I realize that this is impossible to do without hurting steering and handling very badly. My question on this is why aren't people getting the pinion straightened out perfectly and then cutting off the ends of the axle re-clocking it back to a "perfect" caster angle and re-welding them back on?????? It does not even sound like a hard job.


Also I do all of my own work. It is only costing me $300 to re-gear to 5.13.