Gnashing of Teeth

Ruth, the old Jeep, developed a little noise in her belly. Along about January, it went from a whine to a scream so loud It drowned out the engine.   That's the little V8 with a pair of 2 1/2" magnafows on it.   Seemed like it might finally be time to see what all the commotion was about.

I could move the rear output shaft yoke up and down a good 1/16 of a inch.   That will make your gears howl so I pulled the transfer case and checked it over to see what else might be sloppy.   The only real trouble  turned out to be the output shaft so I changed those bearings and races.  There were a few seal issues too.  Pretty much leaked into and out of every seal but the two output shaft yokes so I changed all the seals too.

 

The book said that end play on the output shaft should be between .001" and .005."     Its controlled by a stack of shims on the output shaft.   You assemble everything, torque it all down and then check the end play.  If its too tight, you take it back apart and add a shim.  Too loose and you take it back apart and take one out.  Then you check it again and adjust some more until you get it right.

I usually like to be toward the smaller end of the tolerance range when I'm working on something  but after having this project interrupted by a broken hot water pipe under the slab and having to re-plumb the whole house in a weekend, .005" on the first try looked pretty darned good.       

Two things make these Dana 300 transfer cases fun.  One is that they hang down off the back of the transmission at maybe a 30 degree angle so you can't just perch them on a jack and lift them into place.  The other thing is that about 95% of the thing is iron and steel.

Its heavy.

If you have the Jeep on a lift, its not such a big deal but if you are on your back under the Jeep trying to bench press the thing into position, turn it at the right angle, line up the studs so they go through the flange and then jiggle it enough to get it to slide into place, it gets old in a hurry.  I've never seen a transmission jack that will hold one of these at the right angle and I didn't want to buy or rent one even if I found one so I conjured up a rig of my own.

It bolts to the bottom of the transfer case using three of the bolt holes for the bottom cover.   Just takes longer bolts.   A single bolt attaches it to the jack in place of the saddle.   The 4 lines to  the right of the bolt are grooves that I cut into the wood with a die grinder and a cutoff wheel.   A router would work too.   Similar grooves are cut into the underside of the piece that's bolted to the case.

The two pieces of wood are connected  by a plain old door hinge.  I used a screwdriver instead of the hinge pin.  Originally that was because I couldn't find the pin.  When I got to working with it, the screwdriver turned out to be an important part of making the rig work.   It gave the whole thing a lot of flexibility to help when it came time to jiggle and it let me disconnect the jack from the case and get it out of the way just by pulling the screwdriver out when the case was almost home and ready to be bolted up.

In use, the ends of the turnbuckle rest in the grooves and you select the grooves that give you a close approximation of the correct angle for the case.  Its way too tilted in the picture but you get the idea.

By using the jack and the turnbuckle in combination, you can lift the case, keep it at the correct height and change the angle to match the flange.   You can actualy rotate the transfer case a few degrees relative to the flange to line it all up.  Then its just a matter of moving it forward and jiggling it so the spline on the transmission slips into the transfer case input shaft.  

It took less time to build the rig and install the transfer case than it usually takes to install the transfer case just using muscle and foul language.   My back didn't beat me up afterward either.    I could get used to this.