Slip yoke elminater

[Redneck86]

Im wonderin where i can get a slip yoke eliminater for the front drive shaft. Because i saw one a F150 break when it flexed to much and the drive shaft extended past it and then breaks when it tries to go back. I looked on 4wheelparts and they dont have one my truck. Is there one made for it or do you have to get a longer drive shaft? :huh:

Its a 1986 Bronco with a C6 trans and an NP208 Tcase

 

[Justshootme84]

You might be able to have a driveshaft shop make you a custom driveshaft with a longer slip SHAFT, but I haven't found it to be needed even with a 6" suspension lift. The term "slip yoke eliminator" is generally associated with a slip yoke style output on the rear of the transfer case. While the Bronco t-case has a fixed yoke or ******, the F-series trucks use a slip yoke rear output t-case. Only way to change it to a fixed yoke or ****** type is to swap parts from one of those t-cases. I'm having to do that to the F-350 t-case I'm using in the Bronco. JSM84

 

[Redneck86]

Well you know how the front drive shaft will extend? The F150 i saw had the drive extend too far and when it tried to collapse it broke the shaft and U joints. I was wondering if there was a kit to fix this(I was told it was a slip yoke eliminator but i guess thats wrong :-& #036; lol) or if you have to get a longer shaft.

 

[Broncobill78]

You couldn't find one because they aren't made. You need the slip yoke. JSM is absolutely right, the type you've heard of is for trucks that use a slipyoke to couple the driveshaft to the transfer case. What they do in those cases is install a kit that has a new driveshaft with the splined end of the driveshaft (T-case end) removed and replaced it with a U-joint. The transfer case usually gets a new output shaft with a U-joint yoke and when you're done it looks just like the standard Bronco arrangement with both ends of the driveshaft having U-joints.

The slipyoke in the middle of the driveshaft is there because it needs to be. When the axles articulate they move up & down and this causes the actual distance between the transfer case and the axle to keep changing. The only practical way to deal with this is to have some way of allowing the driveshaft to get longer or shorter as the suspension cycles. I *have* seen one or two setups with solid driveshafts but they were on full-blown competition mud trucks with no suspension at all, just axles solidly mounted to frame brackets but these were trucks designed to roll off the trailer, skim across the top of the mud in 4 or 5 seconds and then get winched back onto the trailer. In trucks like that the slipyoke was a weak point so it was eliminated.

I wouldn't worry about it. Like JSM said it really isn't a problem until you get into the 6"-and-beyond range of lift kits (at 6" it usually isn't needed but tha seems to be the area where you start seeing the occasional failure). IF you're worried about it then install a set of limiting straps. These are made from tow-strap material and one end is bolted to the frame and the other wraps around the axle to support it when you're airborne or one wheel drops off into a crevasse. The straps are plenty strong enuf to support the weight of the axle and will keep it from dropping low enough to blow the slipyoke

 

[STLKIKN]

Sorry guys, but I gotta chime in here before the confusion becomes overwhelming...

A "slip yoke" is the portion of drive shaft that enters the out put of the transmission (two wheel drive) or transfer case (4x4) when there is no yoke bolted to the output shaft. (Stock J**p Wrangler rear drive shaft for instance, or even a mid eighties two wheel drive Ch*v truck)

You can have a fixed yoke that takes a drive ******, or one the accepts a universal joint. Either style of these may use a single u-joint configuration, or can be attatched to a double cardan (C. V.) joint.

The slip spline or slip yoke of a drive shaft can be overextended under compression/ extension (depending on suspension style) if the shaft is too short. Too long of a driveshaft can also cause damage to your truck if it cannot compress fully under suspension travel and it "bottoms out."

Redneck, Tom Woods web site has some good write ups and explanations of what you are asking about, As for the shaft you saw come apart, I suspect it was too short for the application, and a "slip yoke eliminator" kit is not required for that truck.

 

[Redneck86]

Thanks man i guess i just got kinda confused lol.