timzcarman Posted April 15, 2010 Posted April 15, 2010 As the title sudjusts, My gearbox will throw out of 5th when under a fair bit of load. I am about to pull it out and do the bearings and seals, and am looking to get some advice on what to look for to fix this problem? Quote
dat2kman Posted April 15, 2010 Posted April 15, 2010 Worn synchros. After 30 odd years of use they do get a little worn out, especially if you have done a bit of highway use. One question has it been recently "rebuilt" 'cos if the rings are not put back exactly as they came out this could cause it.'The ramp angles on the rings are slightly different front to rear, something like a 4 degree difference in angle, and if installed in wrong place this can cause the synchco to"climb" out of gear instead of "push" or hold in gear. Similar thing can happen when say a box is on "trail" or backed off throttle, it can pop out of gear. Get it pulled apart and renewed, it'll be sweet and last another 30 plus years!!! Quote
NZeder Posted April 16, 2010 Posted April 16, 2010 Also the rear penned nut after 30years can come loose and cause the gears to move just a little and that might be the issues also. Again pull it apart and inspect. Quote
timzcarman Posted April 16, 2010 Author Posted April 16, 2010 Thanks guy's I do remember hearing about a rear nut that has been know to come loose. What options are there for synchros - I believe it is a z box with Brass synchros. Is there any aftermarket options or is genuine only? Quote
twosixty Posted April 16, 2010 Posted April 16, 2010 What options are there for synchros - I believe it is a z box with Brass synchros. Is there any aftermarket options or is genuine only? I can't remember if I got genuine or aftermarket, but I remember that they were damn expensive. Porsche style synchros with a similar pricetag. Another helpful post from yours truely. Quote
Zedsabbath Posted May 15, 2010 Posted May 15, 2010 Sorry guys but it's not synchros, it's the gear sloppy on the main shaft...there is two options; new gear and main shaft OR grind out the 5th gear, rebush the gear with a hardened steel bush then grind it out to a smaller bore size than original to suit the worn main shaft If you only replace the synchro, it will jump out again Enjoy, Pete Quote
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