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Jay Nelson

2003 Gas Gas 280 TXT falling out of gear

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Hey Everyone,

I have a 2003 280 TXT that is having transmission issues. For the last couple rides it wouldn't shift down to 1st or 2nd, and in 4th it would "shift" into neutral on big drops. To put it back in gear I could either shift down (back in to 4th) or up (in to 5th). It would always hold 5th or 3rd. 

Last night the transmission starting dropping into neutral in any gear when going over even medium sized bumps, then would fall back into gear (with a clunk) when stopped.

I have seen the eccentric adjustment video by Jim Snell, and may try that this morning, but I'm guessing there is a more serious problem. Is this information enough for someone to tell me what might be going on before I split the cases?

Thanks,

Jason

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Follow Jims instructions. This should fix it.  

 

These engines are prone to a selector shaft piece breaking. This normally leads to a gear box that only changes up (I think) The only solution is to split the motor and replace the shaft. I dont think that that is whats wrong with yours but be aware. 2012 onwards, the shaft can be replaced without a strip down. I had to do this twice on an 05 bike. and twice on my 13. 

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I think you may have broken the Top Hat, (gear selection spring unit)  the cross bar is sacrificial and breaks before the shaft.

Just remove clutch cover and clutch basket (one bolt in center) and you should see it

gas-gas-pro-gearbox-top-hat-selector-spr

 

 

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Thanks for the responses. I haven't had time to open the clutch and take a look yet. I was however today able to rock the bike back and forth and cycle through all 6 gears no problem, so I tried to go for a roop in 5th, it fell into neutral, and wouldn't shift into any gear either up or down. Had a nice run home :) I will have a look at that sacrificial cross bar tomorrow, if it's intact I'll try to set the eccentric in a better position and see if that helps. 

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Okay so I pulled the clutch and found that the cross bar was intact. The eccentric cam adjustment is changing the shifting capabilities, but there is no position that allows for shifting between all gears, and when I find a position that shifts between *some* gears, and it only works for a couple shifts. When I follow Jim's directions there is never a point at which I can turn the eccentric cam to produce the click. I am thinking about trying to Dremel out the casing for more range of motion as he shows in another video, but I don't really know if 'm on the right track here. It seems like the cam is not performing its function properly. I've resorted to trying random positions and hoping.

I was able to find a position where shifting was working, then I VERY carefully tightened the locking bolt into that position and shifting did not work at all. Maybe the cam is worn and not adjusting the tension properly? I do notice the springs move up and down as I turn it, not up in one direction and down in the other.

Frustrating! Any help would be much appreciated!

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And here's something you don't want to find, it was attached to my drain plug magnet. I noticed I had to hold one of these in the hole for the water impeller when I reassembled the bike, but it was longer. I have no idea where this came from, but I sure am glad the magnet caught it!

Hmm, having a hard time uploading the image, it is a pin about 3mm diameter and 1cm long, not sheared, looks like a complete part.

 

 

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So I got it shifting through all gears after reassembly, added 550ml dexron II, headed out for a ride, shifted great for 5 minutes, after a small drop it fell out of 3rd into "neutral" and wouldn't shift up or down. Turned it off and started pushing. I think I may need to bring it to someone who knows what's up. Looks like the closest Gas Gas tech is about 8 hours away so no riding for me for quite some time. Any suggestions for an interior BC Gas Gas tech would be much appreciated. 

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Here is a pic of the crossbar (which I think looks normal?), and a pic of the pin found attached to drain plug.

Sorry for the series of posts, just hope with enough info maybe someone might know what's going on!

IMG_1284.jpeg

IMG_1287_2.jpeg

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 Do not ride this any more. You will just cause more damage. Zippy is correct. You will need a new shift shaft assembly and I would replace the top hat, just because it makes assembly easier and at the worst gives you a spare.

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I feel really confident you guys have nailed it here, and I'm sure that it is part #13 stuck to my drain plug.  Guess I start looking around for a GG tech, splitting the cases is where I draw the line. 

Thanks a bunch for the help!

Jay

 

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Good luck, hope it is sorted quickly

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Yup that's the bit on the shift shaft that breaks off that I mentioned in my post. Usually happens when the shift lever gets a good wack from a rock or something in a fall. Proper pain in the a*** job. Glad you found the problem. 

 

PS, I called it! Been there done it my friend. I feel your pain. While you have the motor apart take the opportunity to change crank seals and output shaft seals etc. 

 

Good luck. 

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