I thought I was done with the project updates for a while but after this last weekend I do have a few things to report.  First, the good: I finally got some sticky tires mounted on the crawler.

These are 40" Maxxis Creepy Crawlers.  At 8psi I measured them to be 38.5" tall which is a little on the short side.  Despite being height challenged I can't say that the lower stance hurt me during the weekend's wheeling adventures. I think the tires ability to hold a line offset their height disadvantage. 

The sidewall construction is much beefier looking than most of the tires out there, they actually remind me of my old Baja Claws with the sidebiter looking treads wrapping down the sidewall.  As you can see in the pictures above the tread on the side were useful on the rocks.  The extra sidewall beef equates to more rubber, these tires weighed in at a healthy 103lbs each, 6 more than my old 42" Iroks which were much taller.

At 8 psi the tires flexed really well thanks to the really soft rubber compound, I may try running a bit more air pressure.  I managed to run a bunch of obstacles I was familiar with and I can say these tires hooked up much more consistently than my Irok's.  You cold pretty much put them on a line and know they were going to hold whereas the Irok's were a bit of hit and miss.  Scott and Jack were both running a set of worn in Krawlers (which work best at 50% tread) and I managed to do everything they did with the exception of one climb.  I think my narrower track width was the difference on the climb, I couldn't get as good a tire pinch as they did.  All in all I am impressed with the tires, especially how well they hooked up on the maiden voyage.  

One note, if you are wondering how well the standard compound version of these tires would work in the rocks, I don't think you can use my experience to extrapolate performance. From what I have seen, soft compound tires don't need large voids in the tread blocks or sharp edges to provide traction (the gaps between the lugs on the CC's seem small to me), they actually work better when worn down to the point that the edges are heavily chamfered and the tread blocks are shorter.  I think the chamfered edges give more surface area to contact the rocks and the lower tread blocks allow less movement or wiggle which helps the tire hold a line better.  On the other hand, standard compound tires seem to work better with large voids between the tread blocks with sharp edges.  The large voids and sharp edges are what grab and hold features on the obstacle.  In my opinion the Irok tires seem to be a nice compromise between the two camps with slightly softer rubber than the old SX's and large voids between the tread blocks. 

The bad is I blew my transmission again.  I noticed that when in reverse you had to give it a lot of gas to get the car to move and a few times during the past few weeks I had gotten some smoke from the transmission when trying to back out of a tight spot in 4 low. After this past weekend I couldn't get the rig to back up on flat ground in 4 high and the drive train started shaking as I gave it gas, definitely not a good sign. Upon pulling the pan you could see chunks of friction material so it looks like it ate up the reverse band.  If anyone out there has a 4wd TF904 they'd like to get rid of, drop me a line :)

It takes almost exactly 6 hours to tear down the rig to the point where you can get the transmission out (about 12 hours to get it back together). The whole interior, transfer case, both drive shafts and battery have to come out which leaves just enough room to snake the transmission out 

While I have the body panels off I plan on adding some grounds to the PCM wiring which I suspect may be the source of my random power loss issue.  In the process of poking thru the wires I noticed another possible culprit, the main ignition fuse was very loose in it's seat (it nearly falls out with a slight bump), I bent the clips inward a bit so the fuse is held snugly.  

While I wait for the transmission to be repaired I figured I'd get a few major projects done that would have required major disassembly anyway.  #1 on the list is removing the original Summit turbo muffler from under the passenger seat.  Removal can only be accomplished with the transfer case out so now is the perfect time.  I am replacing the muffler with a straight pipe and have added a 18" Supertrapp muffler to back end of the exhaust.   The Supertrapp eliminated a really annoying drone which occurred around 2500 rpms (cruising speed). I am also working on a set of thinner steel body panels.  The previous set was made from free material that was .100 thick.  Free is good but the material thickness was a little more than I really wanted and made the panels heavy to the tune of 35lbs each. I really enjoy the peace of mind the panels give me by enclosing the passenger compartment and preventing intrusions but a thinner panel would serve the same purpose.  The new panels are .070 thick and weigh 24lbs each

Another little project I completed was making a spacer to space out the transmission and motor.  When I installed the Art Carr torque converter a few months back I discovered the mounting pads for the flex plate were a little too thick making it impossible to cinch the transmission mounting bolts down without pushing the torque converter into the transmission oil pump.  I made some temporary spacers out of fender washers and spaced the transmission back .06" to solve the problem.  the long term solution is a spacer that provides a solid mounting surface all the way around the bell housing.  As you can see I miscounted the holes and mistakenly chopped off the spacer a little too short on the drivers side which is what the second piece is for.  I plan on gluing the spacer to the back of the motor so I don't have to mess with aligning it while trying to engage the transmission and motor.

Update 1-7-07 - 4 days and counting till our MLK weekend event. I took the front end apart on Sunday to measure the front inner axles. Both inners are twisting nicely.  I had them apart about a year ago and saw no signs of twisting so I am going to have to blame the motor for these :)  

Also found a caliper with a broken mounting ear.  After exchanging that and swapping the new one in, the master cylinder didn't seem to be pushing fluid.  After a lot of fussing I finally got the Wilwood master cylinder to work but I had to bench bleed the master, then draw fluid down to the caliper by hooking a vacuum source to the caliper bleed screw with a hose setting it new brake fluid attached to the other end of the hard brake line.  Next I hooked the hard brake line to the recently bled master.  Next I attach a hose filled with fresh brake fluid to the bleeder screw and then proceeded to bleed the brakes like normal.  A co-worker mentioned that these types of master cylinders are notoriously hard to bleed and they don't push fluid like a typical OEM master cylinder.  I noticed you cannot pump the reservoir dry, instead it seems to suck the fluid right back in.  My co-worker confirmed this behavior and said they had the best luck by pushing the pedal all the way down and then quickly releasing the pedal allowing it to snap back as fast as possible.  

Update 1-11-07 - I received the transmission back late Monday evening.  Lots of parts were replaced due to evidence of metal to metal contact .  The builder found a few sketcky things done by whoever did the original build that may have contributed to the meltdown.  One other thing we discussed was plugging the breather hole that was located behind the torque converter on top of the pump. On my last roll I had fluid gush from the breather onto the exhaust manifold which caught fire.  After some discussion we both thought plugging the breather and modifying the dipstick tube to be the breather was a good plan.  Little did I know this decision would come back to haunt me later.

 I took the day off of work Tuesday to put the buggy back together.  The last time I did this it took a solid 12 hours and with our MLK event coming up in two days I was running out of time. About the halfway point I fired up the motor and watched as the transmission spun properly as I put the transmission in the various gears. I then proceeded to put everything else back together, Approximately 11 hours from when I started I was ready for a test drive. I slid the transmission into first and nothing..... None of the gears worked. The dipstick showed the proper fluid level but the transmission was acting like it had no fluid so I added more until it spilled out of the dipstick tube.  Still nothing.  Completely stumped I went to bed only to get up an hour later to try something else.  I pulled the high pressure line at the external filter I had added  and set it in a bucket.  I then started the motor.  There should have been fluid circulating thru the system but there was nothing coming out of the hose. So now I knew why the transmission wasn't working, the pickup must not have been submerged.  My best guess was that there was an air pocket that was preventing fluid from the dipstick from draining down into the pan.

The next morning I consulted with the guy who rebuilt my transmission (Don at Don's Transmission's).  He felt the problem had to be the plugged breather. unfortunately I did not want to unplug that breather and wanted to relocate it.  I found a few write-ups on the web that discussed relocating the breather on a TF727 (very similar to my 904)  but they all required the pump to be removed which meant tearing the car apart again (6 hours apart and 11 back together). I decide to drill and tap a hole for a fitting in the tail housing, a location far enough back from the clutches that it should not see shooting fluids and it was easy to get to with nothing delicate for the drill to hit if I went too deep.  I started with a very tiny hole and kept a vacuum cleaner going next to the drill point to catch the chips. Once the hole was drilled I started up the car, placed the transmission in neutral and added fluid till it was full (a good sign since the tube was overflowing last night and now I was able to add more).  Next I rowed thru the gears.  It took a while for the converter to fill but eventually the transmission showed signs of life until finally the buggy moved. 

Now that I proved the theory, I drilled the hole larger and tapped it for a #10-32 pneumatic fitting.  I then attached a 1/4" air line to the fitting and ran it to a temporary catch can/filter behind one of the headlights.  If this setup works good on the trail I want to add a shutoff valve inline and make a more permanent catch can.

With the transmission working and a successful test run under the buggies tires I could finally put all the skins back on.  It's been a while since the buggy looked this nice.

Little did I know the roller coaster ride was not over with yet.  Thursday morning (the day we are supposed to leave for our weekend event) I discover some metal flakes in the rear differential while topping off the fluid.  Curious I decided to remove the diff cover and discover the source of the popping noise we heard 2 weekends ago while I was driving forward on some sand.  it looks like enough teeth to wheel on but I am going to try and find gears and a shop to set them up today.

Update 1-22-07 - Well, I tried to take it easy on them and they still didn't last long :)  Timing was about perfect, I broke on the last waterfall on the last day.  Not sure what broke first, possibly the ears on the long side stub shaft which bound up and took out one or both of the inner axles. The other possibility is they all started to break at once.  Either way some better axles are needed. I decided to try some Alloy USA axles.  I would have liked to go with some Superiors or even the Longfield D60 CV's but after paying to have the transmission rebuilt again and buying a new ring and pinion set I am kind of tapped out. The Alloy USA shafts came in at roughly $800 which included custom machining for the two inner shafts.  The 10 year warranty was also attractive although I hope I don't have to use it much.

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