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Hello from Canada with a missing 5th gear DCT

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I have seen a few others mentioning issues with their DCT's and I figured I would share my experience since sh*t hit the fan today. I'll try and paint a picture with words of what owning this beast is has been like and what I do maintenance wise for background. I'm wondering if others notice 5th gear rattle/noise or any skipping.

I own a tuning shop and tune street/race cars and am mechanically inclined, so I'll be fixing this myself and sharing what I can hopefully in exchanging knowledge in the process. Since I was young I've had a 'thing' for anything with a motor. I've ridden dirt bikes and quads since early teens. Back then it was always someone else's machine. A few years ago I got back into it and got my own.

I bought this TRX520FA7 in September 2019. Initially disappointed by the speediness of it, coming from a 2002 TRX400EX I bought that spring. I understood the 4x4 would come with a sacrifice, but anyways I actually fell in love with DCT and had fun being able to go places I couldn't before. I finally got a trail pass instead of just going to pits, etc. Since getting this atv, I've ridden it all year round (ranging from -20*C to +35*C) and change the oil every three months using dealer filter oil and gaskets. I am now at 2740-ish Kilometers on the Odometer. I'm long outside warranty, sadly. I figured why not dyno it! 28whp & 31 wtq. Not very impressive... I have not modified the bike at all with regards to performance except handling - original factory sized zilla's (love these, on my second set). I've only done convenience things like 2up/storage, windshield (essential in colder months and it takes a beating totally great design easy to remove), heated grips, light bar and a winch (dealer installed warn - been very good to me and all the canams I pull out hehe). Brakes are still good - I do a partial rebuild every oil change (pull the pins and pads, clean them up, dielectric grease. I engine brake mostly so they still have 70% ish life left judging by the indicator. I replaced a front wheel bearing (nailed a stump hidden by snow drift 1st winter and killed the tire instantly) and rear axle boot last summer (the mud puddle had branches and one got up in there and ripped it. rebuilt the axle with new honda boots, waited 4 weeks for them. Haven't had any other issues with that axle. Diff fluid I change every spring / fall because Canadian weather eh.

I took it to the dealer for its first (and expensive) service at 150kms (valve lash check). I then began started having oil leak problems. I took it back and they determined it what the pull-start shaft seal at the case. (this would be Canadian model specific accessory). It sat there for two weeks in pieces so I asked them to put it back together so I can ride until the part arrives. It finally arrives after 5 weeks and they install it. Within a week, its leaking again. Second time around they seem to finally get it to not leak. Since then however my 12v plug and 3rd headlight stopped working and when I went to do my first (so the bikes second) oil change, I noticed the dealer installed the panels incorrectly and broke a tab. They simply didn't reconnect the 12v stuff so I fixed it easily. Since then I've been apprehensive to say the least about bringing it back to the dealer. Generally speaking, the machine is just as capable as trolling through mud, flying down trails, climbing/crawling just as good as any other machine on the trail. It always starts even in -20*C after sitting 3 weeks in a field.

My only complaint is the ultra short gearing. like 1-2-3-4 in very few seconds - I think it should be a (much) taller spread - but it's probably too weak lol. Its pretty bad when an 80's honda air cooled rancher 350 cruises by me and has more top end than mine. I even got spanked by an '02 rancher 420. The old one could also hold wider donuts on the lake around the island too. Topping out at 74km/h is likely a Honda liability thing, like lets keep it slow so less accidents - you know like from the 3 wheeler days still trying to re-establish a 'safe' brand image. So much for 'going out for a rip'.

After the first big service and oil leak issue was resolved, I started to push it gradually more and more without holding back for 'break-in' sake. I began noticing an odd 3-4 crunch, and while cruising in 5th - a distinct rattle/shake sound. Eventually this would become the odd skip feeling here and there, as if the dogs were jumping out a re-engaging. These symptoms were present whether is was using manual mode or leaving 'er in D and letting 'er be. Occasionally during a moment of hard work - like churning butter or crushing though slushy ice, when I would stop it would blink " - ". So I would turn it off, back on and back to normal. Never thought too much of it other than a logical error with the electronics. Resetting always remedied any issue I had previously with the DCT. It happened randomly but never left me stranded.

With the front diff lock it has got me out of a lot of pickles - but sometimes it's a little delayed about engaging so I'm curious about swapping that out for a manual style. I learned to get it engaged before going through the sticky icky - but sometimes you forget. I find being gentle on the throttle and turning full left to right helps a lot.

The ECU wires are in a bad path, the seat notch sits on them, add some foam but secure it, or tape it up a lot with e-tape. something, anything help it!

Well, today the skips in 5th became more frequent and eventually lost 5th. I suddenly lost power riding along groomed/hardpack snow, free revving so I lifted the throttle and came to a stop. I was downshifting it and it appeared to initially lose all of the gears. So I did the usual reset, it came online as usual so I kept going. It held 5th for a few moments then fell out again. One more time try fifth - hard crunch but no gear. So I got home in up to 4th only - and I rode it as usual otherwise. Reverse became an issue as well, although if I rocked the bike it went in. I checked the dipstick several times on the way back to the car, never saw any shavings just fresh oil, no shiny grains. So I dipped on the crew early and was fortunate to get it home.

Since I'm out of warranty I'm debating on what to do. I feel like if I fix it, its a bad design and it may fail again. Based on how it progressed, I'm confident that it was the gear not engaging fully on the dog or the idler. The rattle only heard in the drivetrain in 5th may have been one of the two gears having too much thrust play and it was slapping around a bit, wearing the dogs as the gear had more and more runout - eventually stripping the dogs off. I will do a full teardown and inspect to see what the murder scene is like.

I'm seriously thinking about changing the gear ratios while I'm in there. Definitely need to address the thrust / rattle issue for 5th and upgrade to harder materials. How on earth am I supposed to eventually boost this thing if it won't even hold up to stock power? I was gonna do a HMF pipe this spring and maybe a snorkel. Maybe not?

I was also considering before this happened - Using the final drive gear selector gearbox as my target for changing the ratios in a coarse way without having to split the case. But now I guess many options are on the table. I'm thinking about converting as many things to mechanical as possible, possibly including the gearbox. Does a footshift model run a different ECU? I was thinking about micro-squirting it and tuning it but dynojet recently released something that would be easy enough too if the DCT stays.

So today the Canam finally had a leg up on reliability after 1.5yrs... but at least the Honda didn't leave me stranded null I'll start a repair thread once I start digging into it. I can only find limited service info on these so anything to help make it easier for the next they. null Easiest way to drop the motor on an atv?


Any advice/knowledge/insight is greatly appreciated thank you!

In case you're wondering why I have the front axle engaged for the dyno... It's because the computer is too fancy to allow total rear wheel spin past 2nd gear (this makes getting roudy on the ice hard). Probably a dct safety feature. I did have an extra jack stand under there as well. Got around the nanny by going in 4wd and keeping it all moving together.

Here are the some pics and dyno graphs:





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Welcome aboard.  First I've heard of DCT transmission issues with the hard parts.  It's usually electronic or oil pressure related.  Yours definitely sounds like gear dogs though.


@toodeep have you seen this yet?

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Welcome to ATVHonda lighttouchtuning!

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