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TRX400ex transmission bushings orientation

684 Views 1 Reply 2 Participants Last post by  SlammedRanger
Hello, first time poster here.

Unfortunately my partner who was helping me take the motor apart disassembled the mainshaft before I got a good look at the orientation on this. This question is not addressed at all in my service manual. In full disclosure this is actually an xr400r dirt bike which of course has the same transmission as the TRX400EX.

The the main shaft on this bike has an small oil passage hole drilled into the shaft where 5th gear would be. In addition to this hole, there is a small oil hole drilled into the bushing that the 5th gear sits on. My question is how to orient this bushing with the hole in relation to the hole in the shaft. Does it matter? Other transmissions I have seen online require these holes to be lined up.

The hole in the bushing cannot line up directly over the hole in the shaft, due to the splines. Should the hole in the bushing be close to the hole in the shaft, or perhaps opposite of each other?

Any advice from the experts here? Thanks in advance.


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My gut is telling me it dosnt matter where you put it because the groove in the bushing is deeper then the splines so no matter where you put it the oil will travel where it needs to. I wouldnt put it all the way on the opposite side or anything. Just to be sure the oil can make it to the hole properly. But it has been a couple years since i had a 400ex transmission apart. Welcome to the forums!
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