I was able to get the transmission/transfer case pulled out and reinstalled this weekend. I did not find a problem with the clutch, but I did find a problem.
Before I get too in depth with what I found, a few quick pictures of my transmission jack AX15 mounting plate that I made. It worked perfect, and held the transmission securely.
I built the mounting plate out of wood which bolts to the threaded holes in the bottom of the transmission case.
The wood plate then bolts to the transmission jacks steel plate. I also used a strap, but not necessary.
This set up worked perfectly. Even though it bolts the transmission to the jack toward the rear of the transmission case, it balances out perfect. That Dana 300 on the back weighs more then the front of the transmission/bell housing.
Upon re-installation, I loosened the transmission to wood plate bolts some, to allow for a little "wiggle room" to make installation really easy.
I "thought/assumed" the "ticking" sound I was hearing, that was coming from the bell housing area, was originating with the clutch. Maybe it was, I don't have that "ticking" sound anymore, but I never did find a problem with the clutch assembly. The Centerforce clutch has approximately 28,000 miles on it. I never had any complaints with it, except the ticking sound that developed approximately 3,000 miles after the AX15 install. The clutch is most probably still fine.
For a recap, I am running a Novak AX15, 258, T176 bell housing that bolts to an adapter plate on the front of the transmission. All stock clutch linkage, Centerforce Stage 2 PP and Disc. Novak supplied pilot bushing.
The clutch disc looked fine, the center hub, where my finger is, was loose, but I believe that they are made to move a little:
I really thought I was going to find a problem with the Centerforce weights, but they were all intact, no damage evident. The weights do fit loose on the metal retaining ring, so maybe the "ticking" sound I was hearing was coming from the pressure plate???
This is the only problem I found, the Novak supplied pilot bushing was turning to dust, with less then 5,000 miles on it!!!!
If you look close, you can see black dust/debris in the cavity behind the pilot bushing. When Novak sent me this bushing, they told me that it was an "Oilite" bushing, that no lubricant was needed. Well, I don't think this was the case. The bushing was bone dry, and upon removal, which destroyed it, it was more silver in color then bronze, leading me to believe it has a high iron content, and was not self lubricating.
The good news, the input shaft is fine, and the front bearing in the transmission seems fine, too. No real play evident in the input shaft. If you look real close at the above picture, you will see a raised ridge toward the back of the pilot bushing. This is where the tapered end of the input shaft rode. It is pretty concentric, and wear to the bushing is also concentric. This leads me to believe that everything is spinning close to "true". Before I installed this transmission, I checked the crank to bell housing center bore with a dial indicator to check the run out. It was well within spec, so I am fairly confident this damage was not caused by an alignment issue ?????????
Of course, I did not discover the damaged pilot bushing until Saturday morning, on a holiday weekend. No parts stores around me had a pilot bushing that would work. Well, sinse I have had two crappy supposedly "oilite" bushings fail in this Scrambler, I figured what the hell,and tried this little number:
This is a needle roller bearing, surrounded by a spacer. It fits in the outer ridge of the crank. This particular unit works with 4.0/AX15 equipped Wranglers. It was in stock at Napa, so I am going to try it. I would have preferred a real "Oilite" bushing, but I was unable to locate one. One saving grace: This bearing rides in the outer portion of the the crank, closer to the splines of the input shaft. The bushings fit in the inner crank cavity, toward the end of the input shaft. "IF" this bearing fails, maybe it wont tear up the end of the input shaft where the bushing rides. Hopefully it does not fail!!!!!
Before installing this pilot bearing, I test fit it to the input shaft. It fit really well, not too tight and not too loose. My input shaft has an OD of .75, the ID of this bearing is advertised at being .763. That would appear to be a "loose" fit, but it seems to fit fine. This bearing ID is what Jeep used with .75 OD input shafts, so fingers crossed it will be good to go. According to National Bearing, a pilot BUSHING should have an OD .002-.005 larger then the OD of the corresponding shaft. I could not find a recommended tolerance for pilot BEARINGS. But, Jeep used this bearing with .75 OD input shafts, and Novak said I should be fine, so fingers crossed. Advance Adapters also recommends this pilot bearing.
Installation was simple using a seal driving tool as a driver:
I was really concerned about this, looking at the bushing/bearing from the side, it does stick out from the crank, but not past the flywheel bolts:
I thought I was going to be out of luck. I was worried that the pilot bearing assembly was sticking out toward the rear too much, and that it would foul on the input shaft splines. I should have made some careful measurements before hand, but I didn't. Figured what the hell, bolted in a NAPA replacement clutch, and a new throw out bearing. More on the TO in a bit. Went to slide the bell housing/transmission/Dana 300 assembly back into place, with much apprehension, but it slid right in. I was able to gently push it all the way in, did not have to fight it or pull it in with bolts.
I then reassembled the rest of the drive line/Scrambler. As for the TO bearing, the one that came with the kit seemed really crappy. So, I bought a new SKF HD TO bearing and installed it. I have not had any problems with the "seem to be crappier TO bearings", but I decided to install a "better" TO bearing.
Anyway, once the Scrambler was reassembled, I fired it up. The clutch works fine, shifts through all the gears, no vibrations. Seems really good. UNTIL you push in the clutch pedal!!!!!!!!!!!!! Right when the TO bearing contacts the PP fingers, I can here a distinct "whirring" sound. No sound present idling with transmission in neutral, or idling in gear with the transfer case in neutral. I only hear the sound right when the TO bearing hits the PP fingers. Nice.
The SKF TO bearing turned fine by hand before installation, but it did seem to have more internal resistance then the crappier TO bearings. I am "hoping" that maybe the SKF bearing was an older unit, sat on the shelf for awhile, maybe the grease just needs to get hot a few times to become more fluid. That's what I am hoping.
One last picture of the "guilty" party:
Let's see:
Original T176 rebuilt/reinstalled upon original Scrambler rebuild
Rebuilt T176 pulled and replaced with T5 #1
T5#1 obtained cluster gear bearing surface issue, replaced with T5 #2
T5 #2 blew, repalced with T5 #3
T5 #3 blew, reinstalled original/rebuilt T176
Pulled T176 out to install AX15
Pulled AX15 out to investigate clutch issues, reinstalled AX 15
I could of saved a bunch of time/money keeping the T176/driving slower.
Anyway, I am going to drive the Scrambler around some and see if the "assumed to be TO bearing noise" goes away with a little driving. If not, good thing I have my "AX15 wood plate" thing.