slip yoke eliminator...brand? recommendations? install help?

i used the black diamond kit that replaces the mainshaft. here is a write up of a similar install.

said, if i had it to do over again i think i would use the RE "hack &tap" setup which is cheaper, much easier to install and regardless of claimsto the contrary, i believe it to be just as strong.

my install was fast and easy except for one part. keeping the oil pick up tube connected was a _bitch_ during reassembly. go with the "hack & tap" and be done with it. no point in making it harder than it has to be. i know of _no_ advantage to using the main shaft replacement system.

Look at the two mainshafts...look at the difference in thickness south of the syncro bearing surfaces. That's the advantage.

• * * Matt Macchiarolo
  formatting link
  formatting link
  formatting link

The main advantage of the shaft replacement type is a stronger and shorter output shaft. Actually, the "hack and tap" system can work if you do it carefully. One thing you don't want to do and that is to drill too deep. If you do, you get into the narrow part of the shaft and really weaken it. If you do the type of wheeling that breaks things, get the HD shaft replacement type of SYE. Otherwise, the "hack and tap" system can save you some bucks (you still have to get a new driveshaft, though.)

Tom Woods recommended the JB Conversions kit, which uses a stronger output shaft and a splined output yoke. Much stronger than the other main type, which uses a shortened & tapped stock output shaft. FWIW, I installed a Currie kit on my '94 YJ which just uses a shortened & tapped stock shaft & flange plate to accept a CV shaft. It held up fine with the stock drivetrain. I replaced the entire t-case with an AtlasII when I upgraded the axles & added lockers.

As for doing it yourself, and bearing in mind I am a former ASE Master Tech who's done many transmission repairs before I attempted this, it's not really a very complicated operation. FWIW, I did mine by splitting the case in the vehicle, rather than pulling the whole unit out of the vehicle. Hardest part of the entire operation was getting the front output yoke's nut loose, but once that was accomplished the replacement went very easily. Now, the JB Conversions type kits are a bit more complex and I'm not sure you could do it the way I just described. Once Installed, adding on the new rear driveshaft is a piece 'o cake.

And then there are those of us stuck with the np242 transfer case. KH

theres no real world advantage to having a stronger shaft. the existing shaft is more than adequate in its original length, and shortening it only makes it stronger. in _all_ my years of tinkering ive _never_ heard of anyone ever busting a stock 231 main shaft.

in theory thats great but thats not a real world advantage unless the stock mainshaft is prone to breakage. stock mainshafts dont break as it is, theres nothing gained by doing the mainshaft replacement.

why is shaft strength relevant when the stock shaft will never break?

Never say "never". ;-) Sure, it's easy for you to say. You don't even *have* a slip yoke! :-) (I'm just jealous...)

while true, experience tells me that if there ever is a bind up that serious, the chain or drive gears are gonna give long before the mainshaft.

Well, yes and no. I have seen reports of people breaking the "hack and tap" due to too deep a hole drilled, weakening the shaft at the narrow point. That's all. I suppose, if you beef up everything else, you will break the weakest link if you try hard enough. Actually I will probably get the "hack and tap" for my TJ, though.

...actually, so do I. Just don't tell Nathan... ;-)

improper installation doesnt count. :-)

Hey, I'm arguing here! Don't confuse me with logic! ;-)

ha ha...definately a new one!

Hmm, there one someone here about a year ago who did just that..can't remember who, but his mainshaft split right at that narrow section.

• * * Matt Macchiarolo
  formatting link
  formatting link
  formatting link

improper installations (drilling into the narrow section when the instructions are clear on that) does not count.

• * * Matt Macchiarolo
  formatting link
  formatting link
  formatting link