cheerokee front drive shaft

[west747]

i am looking into getting a cheerokee Front DS to shorten for the rear of my YJ. my question is how does the cv joint on the cherokee shaft mate up to the t-case? does it use a flange or u-joints and straps? i have never seen a front cherokee drive shaft so i have no idea. thanks!

 

[Bounty__Hunter]

Best way I've found is to use a RE flange on the transfer case (H&T) and the front half of a double cardan joint from a Ford like the Explorer or Bronco II.

 

[GreenReaper93]

So it can be done with a cheerokee shaft??? I'm looking at the hack & tap system for my t-case, and have the parts listed above readily available for a drive shaft...

 

[graewulf]

the double cardan has straps & bolts on both ends.

 

[Bounty__Hunter]

the double cardan has straps & bolts on both ends.

The double cardan TJ and XJ front driveshafts attach with strap and bolts only at the differential end, and with bolts through the back of the yoke at the transfer case. The doublecardan end of the driveshaft is threaded to accept the bolts from the backside of the transfer case yoke.

 

[graewulf]

the double cardan has straps & bolts on both ends.

The double cardan TJ and XJ front driveshafts attach with strap and bolts only at the differential end, and with bolts through the back of the yoke at the transfer case. The doublecardan end of the driveshaft is threaded to accept the bolts from the backside of the transfer case yoke.

duh! what he said.... (i knew that...)

 

[west747]

so does that mean that i can bolt an xj front driveshaft to the yoke that came with my AA SYE? or will i need something else?

 

[Bounty__Hunter]

Not if the yoke is threaded. You would be putting a threaded double cardan joint up against a threaded yoke.

 

[west747]

Yeah. The AA SYE kit include a yoke that is designed to take a strap so it isnt threaded. it wouldnt be a big deal to drill it out anyway. thanks for the info.

 

[GreenReaper93]

Hey Bounty, I ordered a hack n' tap from RE... you said there are CV flanges from Ford Explorers and Bronco's that would match up? Funds are frozed, so I have to be as frugal as possible. Thanks man!

PS. Sorry to Hi-Jack this one West. :wink:

 

[avyoung]

Is the front driveshaft strong enough to run in the rear? They are usually pretty small and not built as strong because they do not have as much torque as the rear.

 

[graewulf]

Is the front driveshaft strong enough to run in the rear? They are usually pretty small and not built as strong because they do not have as much torque as the rear.

OK, i'd love to hear the logic behind that one.. how can there be less torque if its hooked to the same engine, and same gear ratio diff as the rear shaft? they may be used less, but when under load, the torque should be pretty much the same.

 

[avyoung]

The front driveshaft is only used when in 4wd, splitting the torque of the engine over 2 shafts. The rear driveshaft is used for 2wd spreading the torque over just the one shaft. That is why all of the lazy idiots have started dropping V8's in and going to all wheel drive. Then they do not have to beef up the rear end. If you have a part time system look at the differance in the driveshafts. The rear is far superior and about 2 times the size.

Same thing with rear axles. You want a 44 if you can but really don't care as much about the front. If you throught the 30 in the rear you would tear it up pretty quick.

 

[west747]

the stock cherokee front drive shaft i am using is signifcantly BIGGER than my stock 89 YJ rear driveshaft.( picked the driveshaft up today :lol: :lol

 

[avyoung]

Sweet, I just thought I would through it out in case is was a cheezy little one like most have on the front.

 

[graewulf]

The front driveshaft is only used when in 4wd, splitting the torque of the engine over 2 shafts. The rear driveshaft is used for 2wd spreading the torque over just the one shaft. That is why all of the lazy idiots have started dropping V8's in and going to all wheel drive. Then they do not have to beef up the rear end. If you have a part time system look at the differance in the driveshafts. The rear is far superior and about 2 times the size.

Same thing with rear axles. You want a 44 if you can but really don't care as much about the front. If you throught the 30 in the rear you would tear it up pretty quick.

huh? the full torque is delivered to both shafts... same thing as if you lock your rear, full torque to both wheels (which is why you tend to break things more with a locked rear, no torque split)... AWD allows torque to split between the 2 because it is an open diff in the transfer case.. and then it only splits when the wheels spin... if all 4 are solid to the road, there is full torque to all 4 wheels. the reason they use a seemingly lighter shaft is because the rear shaft is over 2x the length and has more of a chance of twisting under load.

Its not the torque that tears it up, its time with torque applied, you can apply more torque to a lighter rear if its only done some of the time... lessens the chance of tearing it up over time (time being the key factor)... Something else to consider - many front Diffs use reverse cut gears which is why you can run a lighter rear and get the same strength.. my truck had a D35 in the front, (D40 in back) with reverse cut gears which would easily outlast a forward cut D40 in the same spot (front of vehicle)

if you were to remove the rear shaft, put it in 4wd you would still have the same torque appiesd to the front wheels as you would the rear in 2wd, or either in 4WD. the selec-trac in full-time splits torque when a wheel slips... and by different gearing front to rear...

(ok, another good debate here...lol)

 

[avyoung]

Didn't you just about say what I did? The front end is not designed to withstand 100% torque. With the AWD I was mostly refering to SUV's like the Ford Explorer thad will not even offer a part time system on their V8 models. They did nothing to upgrade the drivetrain to handle the extra power except put a full time t-case in.

By the way those of us with SWB Jeeps have a longer, and smaller Front drive shaft. I would guess the front is 1.5 to 2 times as long.

 

[graewulf]

True... but the torque isn't split, it is carried to both shafts fully... the front does get the same torque as the rear, just not all the time... that's the difference I was going for. the front is designed to handle the same torque as the rear, just not for prolonged driving. the reverse spline in the front diff actually strengthens what would otherwise be a weaker link.

 

[Snitty]

the torque is definitely split, and the front is definitely not required to handle as much as the rear... if an engine and drivetrain produces X amount of torque... then it produces X amount of torque.. period... when i 4wd, there is no way that each axle gets X amount of torque, the most one axle can get in 4wd is 1/2X... unless there is a differential in the Tcase.. if there was NOT a split, then that means that each axle gets X, meaning there is 2X together, not possible when the powertrain is only producing 1X.

the reason axles break more often when locked is becaues the torque cannot be disposed into a free spinning tire... instead, it is forced to be directed into either of two stationary wheels...

look on www.jeep.com... read the 4wd system.... quote "the torque is split 50/50"

the rear driveshaft IS designed stronger than the front, and the front will NEVER see the torque that the rear does in 2wd... that is why it is not crutial to upgrade a front axle when it is crutial to upgrade a rear

 

[graewulf]

So if what you are saying is true, then if I put it in 4WD, jack the front end off the ground, step on the gas, the torwue delivered to the rear wheels is 50% of the output? that makes no sense. it should still be 100% of the torque, and the front, which is hanging in the air should get the same amount of power applied to it.... the only way you can split torque is through gearing.. this doesn't make sense... I know what they say, but when you think about it it really doesn't add up....