you will want to contact Les at LTR, he has dealt with this. My buddies Sachs on his GG300 did the same thing. I think it was a tolerance issue with the bushing. Said he had seen it on a few huskys as well. The answers you seek are here...
So I sent the shock out to Les today. Interesting reads on his website. To maybe help any others that may be searching in the future on here for insight into any shock problems they may encounter I'll post some of my explanations I emailed to Les about what I was experiencing and a little bit of his response. I was so pleased with his patient explanation of some of the possible issues to me. It's really nice to have acces to some one that really knows their "stuff" and also is good enough to try to educate their customers in between their hard work instead of just responding, something like, "just send it in and we'll look at it".
Thanks again Les, and if theres anything wrong with me copy and pasting this just let me know.
BTW. this is on my 08 610 with a lil over 7,000 miles on it.
If you go to his site there was some interesting stuff I never heard before.
http://www.lt-racing.com/html/sachssuspension_topics.html
Interesting point in bullentin # 3 about the above
You might want to take a look at a few other things before you send it off to me! The typical failure is a loss of damping/very springy action and not what you seem to describe
The shock not returning is NOT a typical issue for the 610.
1) Make sure the rebound adjuster is not turned in too far, if it is closed off (fully clockwise) it will exhibit this slow return issue. 12-16 clicks out is a good starting point.
2) Check linkage and swing arm for binding and frozen bearings.
3) Your shock does not have the circuit that creates the "moaning" sound that the others do, and the better design TE610 style piston ring is what we use to fix the other shocks non-damping issue!
A further explanation from me about what I had happening
Hey, Thanks for the reply Les. I did the other day pull the linkage off to see if it or the swingarm was binding. It seemed to be OK on it's own. That's when I realized that I would probally have to undo the swingarm to gain a couple inches of clearance to actually get the shock all the way out. I've played with the rebound clicker and haven't seen any changes. I'll try it again to though. Funny thing is how suddenly the problem popped up. For almost the past year I have had my rebound clicker about 4-5 clicks AWAY from the full counterclock wise setting. Then a couple days ago while I was doing some gneral stuff, nut and bolting etc. I decided to go another 4-5 clicks in the same direction. So turning clockwise another 4-5 clicks, for a total of 10-12 clicks AWAY from full counterclockwise, just to see what difference I may feel. And the very next ride, in the first 5 minutes is when this problem started.
So, update, I just came back in from playing with the rebound clicker in every which direction, no difference. If I am off the bike it push hard down on the seat it will compresss the normal couple inches and rebound VERY slowly with a kind of crunchy, or sucking sound. I know, diagnosing sounds online is fun... LOL.. If I am on the bike it will compress normally it seems, but then of course only rebound maybe a half inch, so it is still kind of preloaded more than usual and then of course very stiff. There does seem to be a very thin coating of oil on the shaft of the shock. Would that be normal or a sign of a leaky seal? That's very interesting about your point # 3 you brought up to me. Nice to see that us 610 owners have some things working in our favor suspension wise compared to it's lighter more nimble brothers.. LOL
And finally, Les' response just before I finally got it shipped out to him. Hopefully his online diagnostic is correct and it will be a relatively easy and inexpensive fix as I don't have lots of funds lately for the hobby I love so much. Thanks again for all the help and patience Les..
Okay, with your further description I think I know what it is. It should be no problem at all to repair and will be just a service. I will verify a couple of things when I see it here, but I suspect that the reservoir piston height was not set correctly when first assembled.
If the floating piston is bottomed out in the bore of the reservoir, the nitrogen pressure is NOT being applied to the fluid. This pressure is what pushes the rebound adjusting needle against the adjusting screw and I am willing to bet it is seated fully into the bleed port allowing no rebound bleed whatsoever, essentially a hydro lock. This will almost cease any rebound or return movement of the shaft. This situation can be a real party to disassemble!
The pressure onto the fluid also pushes against the shaft seal that actually makes the seal "seal" that is why you have some fluid residue from here.
Sorry If this long, just want to try to make it easier and quicker if others run into issues with their shock, 610 or not.