Guest Khromalusional Posted June 23, 2007 Share Posted June 23, 2007 Guys, Just removed my 4 speed tranny from my 71 240 last night and noticed a few things. 1. Pilot bushing came out in pieces. 2. Cluches splines had a nice sized wear groove where the pilot bearing was rubbing on it. 3. the input shaft moves! I can jiggle it back and forth a few mm both ways. Is this a bad bearing? What can cause this? Is there something i can do? I have minimul knowledge on taking apart a tranny. Is this something i can do? I was thinking about cracking it open and looking at it anyways. don't have a press at home keep in mind. Thanks Quote Link to comment Share on other sites More sharing options...
JimmyZ Posted June 30, 2007 Share Posted June 30, 2007 Some slop is to be expected. Wouldn't hurt to take it apart and see what's up though. I rebuilt my 4 speed a few times before chucking it. (Replaced synchro rings and bearings. Always drove it hard) Just pop open your Haynes manual and arm yourself with a GOOD set of snap ring pliers. You will cuss like a sailor w/o good S-ring pliers. I built my mainplate holder out of wood and clamped the wood in a vice. A 1x10 and a hole saw are all that you need to make the mainplate jig. Remember to avoid scratching the mainplate surfaces if U can. (Hence the use off wood) Manual tranny's are surprisingly simple to rebuild and you'll get a nice sense of accomplishment to boot. Use the manual for help on replacing your detent balls and get a few pizza boxes for holding parts. There are two bearings which can cause this. The ball bearing on the input shaft is probably due for replacement. Inside the back of the I-shaft there is a needle bearing which has it's ID running on the mainshaft. When you take it apart check out the mainshaft snout where this bearing rides. It might be chippped from the runout of the shaft. If the bearing surface is compromised then it will have to be built up and precision ground by a machine shop. For building up the shaft they should use an acetylene or plasma metal spray rig to deposit a surface with a high hardness. (I'm guessing Rockwell 50-65C should do) Surface needs to be microfinished after grinding to suit. (Machine shop should know to do this) Play resulting from slop on your mainshaft/input shaft is not good. At this point you have to ask if holding on to the old 4 speed is worth it. Once certain tolerances have run out there is no saving a manual tranny. Replacing bearings is pointless after a certain point. Five speed trannys are better built. I miss the nostalgia of the 4 speed but love the toughness/reliabilty of the 5. My 2c Jim Quote Link to comment Share on other sites More sharing options...
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