my SYE alternative

[fallacist]

Yes, the shaft is only shortened 1-2". But with a SYE there are other changes that reduce the load on the shaft. The yoke is shorter as well. I just measured mine and the stock yoke is 6" from the end to the center of the u joint, while the yoke I use for my HnT is 4", so that's another 2". Then there's the fact that on a sye to yoke is always bottomed out, as opposed to a sy where there needs to be room for travel. Let's say 1.5".

Cut the shaft 1.5", yoke is 2", and travel room is 1.5" for a total of 5" more leverage on the shaft and bearings. On my 99 the distance from the output flange to the ujoint center is 4.5", or about half of the stock setup. That's a huge change.

As many others have said, this is where I'd be concerned with this setup. The concept is fine as long as the tcase can support the load. Which is questionable.

I asked the fella who makes these about the durability. He said the shafts are hardened, and should have no problem supporting the weight. He said he's done about 40 of these for jeeps and hasn't had any negative feedback since.

It seems like physics/geometry would tell us that this is questionable, but is there anyone who has personally seen this kind of shaft damage a t-case? I mean, I know I asked for thoughts and opinions, and I'm totally open to hearing everything, but has anyone actually used this set up and had trouble, or is it all speculation?

To me, cutting my output shaft for a HnT would concern me more about about structural integrity than using this DS

 

[srimes]

The shaft is fine, no one is worried about that. The issue is what's supporting the shaft.

Taking a bar of steel and cutting off a piece doesn't weaken it, it just makes it shorter.

 

[zachandandy]

I'm a little confused where the extra load on the t-case would come from? The stock slip yoke slips out at droop and under load, the t-case doesn't blow up? If anything, the double cardan joint eliminates some bind at the slip yoke and reduces potential ujoint bind, which would increase stress on the drivetrain. I don't see the concern with this driveshaft design.

 

[Flyfisher]

Surprised nobody has mentioned the OTHER reason for doing a SYE. If you break a rear DS on the trail without a SYE, you cannot drive the vehicle without loosing the transfer case fluid (unless you jury-rig some sort of plug). With a SYE...no worries about going home on with front wheel drive. Without a SYE, you'll need to carry a spare shaft on the trail if for no other reason than to keep the TC from pumping all its fluid out the rear.

 

[VAhasnoWAVES]

Ummmm... Most SYE and H&T kits use a new tail come creating a sealed output and eliminating this problem. '97 and newer comes factory with a sealed output. I didn't do anything but "hack" and "tap" to install my H&T.

I don't recall what year the OPs rig is. This may be a non issue for him.

 

[Cottontail]

exhibit A:

exhibit B:

Ok....so I am about to finish my H & T. I am using the stock front XJ drive shaft. I have a Ford 8.8 in the rear, which doesn't have a yoke. It has the flange that bolts onto the differential. Which exhibit should my drive shaft look like?? And if it needs to look like exhibit B, I should just use shims to tilt the axle upwards?

 

[ratman572]

I did mine using a combination of these two theories and have had excellent results. I bought the powertrain components yoke, and drilled and tapped the tailshaft on my 231 with a 3/8"-24 around 1" deep (yes, it was a PITA). I also machined a special retaining washer out of 303SS and siliconed the OD and where the bolt passes through to keep the lube in the TC.

I was then able to use a stock-length front DS out of a AW-4/231/D35 rig with no modifications. These driveshafts (although more rare now than 3 years ago) are still very inexpensive at pick-it yards all over the country.

The length of the previously mentioned driveline comes out to be perfect in length for my AW-4/231/D44 with 6.5" leaves/blocks/shackles. The slip yoke on the shaft has more than enough travel to accomidate a full droop/full compression suspension cycle with ease. I am currently using some degree shims under the leaf packs to give me around -2° pinion angle (which allows for some spring wrap when you lean on the skinny pedal).

The first shaft lasted 30K of daily use, and wheelin every so often (twice or more a month in heavy use).

On the road, smooth as butter, -no vibes anywhere in the speed range whatsoever.

Now, what I did sacrifice by not going with a SYE kit was the fact that my output shaft on my 231 is not nearly as beefy as a SYE shaft. In addition, my tailshaft is still rather long, -which does ever so slightly increase the angle on the double cardan on the output shaft of the TC.

I am sure that the extra angle on my setup contributed to the early failure of the first shaft I used. Now, with that being said, I didn't really care because I was able to score another one out of a disco rig that was literally in brand spankin' new condition for less than $30 from the pick and pull yard, -how can you squabble about that? That was one of the main reasons I wanted to be able to use a stock front DS, no custom Tom Woods, or anything like that (Tom makes killer stuff, just not for $30!). One other (seldom mentioned) advantage of leaving the tailcone on the TC is additional driveshaft support (there is actually a sleeve bearing in there that does a really good job at supporting the driveshaft, assuming the proper yoke is used).

I guess what I am trying to say after all of this is that I love my setup, but it isn't perfect because of the high-angle on the TC output shaft (due to the long tailshaft). The advantage is inexpensive stock front driveshafts.

Like everything, it is a compromise as to what works for your particular setup, how much it costs, and how easy it is to find another one when you break it.

 

[SolarBell]

Ok....so I am about to finish my H & T. I am using the stock front XJ drive shaft. I have a Ford 8.8 in the rear, which doesn't have a yoke. It has the flange that bolts onto the differential. Which exhibit should my drive shaft look like?? And if it needs to look like exhibit B, I should just use shims to tilt the axle upwards?

If the TC side of the driveshaft is a double cardan, it needs to look like exhibit B. Use shims to point the pinion up, but measure first to make sure you get the right angle shim.

 

[fallacist]

Ummmm... Most SYE and H&T kits use a new tail come creating a sealed output and eliminating this problem. '97 and newer comes factory with a sealed output. I didn't do anything but "hack" and "tap" to install my H&T.

I don't recall what year the OPs rig is. This may be a non issue for him.

Correct, I have an 01, so no leaking issues for me. In fact I'll bring my stock driveshaft with me on trails, just in case something happens. Considering my new DS is pretty beefy, and my rig is a DD, I don't thin I'll have any issues, but I am knocking on wood as i wrote this.. hah

 

[CraserXJ]

by shimming the pinon up you are reducing your caster angle. How big of tires are you running? with small tires it will have a tendency to wander on the road. Bigger tires not as much.

 

[zachandandy]

Caster angle on the rear axle? Or are you thinking of pinion shims on the coil sprung front? The rear axle can be shimmed to any angle, as it is a non steer axle and will not cause wandering at any angle.

 

[kastein]

Surprised nobody has mentioned the OTHER reason for doing a SYE. If you break a rear DS on the trail without a SYE, you cannot drive the vehicle without loosing the transfer case fluid (unless you jury-rig some sort of plug). With a SYE...no worries about going home on with front wheel drive. Without a SYE, you'll need to carry a spare shaft on the trail if for no other reason than to keep the TC from pumping all its fluid out the rear.

on a 96 and later XJ this is moot as the seal is built into the transfer case housing instead of riding on the slip yoke. That's why the first shaft he received was a few inches too long.

If you are wheeling a 95 or earlier XJ with the stock rear shaft setup, you should have a 1 liter bottle of coke, a roll of duct tape, and some extra ATF in your trail kit. Usage instructions:

* drink coke
* swab off tailhousing so it's clean
* cut coke bottle to fit over, duct tape in place
* top off transfer case

by shimming the pinon up you are reducing your caster angle. How big of tires are you running? with small tires it will have a tendency to wander on the road. Bigger tires not as much.

rear axle not front one dude...

 

[barillms]

SYEs do 3 things: 1. They remove a weak link in the 231, the long rear output/small diameter shaft isn't strong. Plus the splined slip yoke is weak also. 2. It shortens the transfer case. 3. It allows use of a longer rear driveshaft, which in short wheelbase Wranglers with 6-8" of lift is a HUGE benefit because the shorter rear output changes the rear driveshaft lemgth & angle considerably allowing for use of a CV which can operate at a steeper angle. 4 door XJs don't always need an SYE because the wheelbase is long enough for the rear driveshaft to operate within the angle limits. No binding occurs with moderate amounts of lift. You still must tip the rear axle pinion upward to match the driveshaft angle. An SYE is always a great upgrade, but not always 100% necessary.