They were composite; now they're metal, albeit some soft alloy. Lasting 6 - 8 years is frankly conjecture on his part; he has no idea how often you park it. BUT....those tension springs, SUPER IMPORTANT because if they're not tight enough to press those teeth firmly into the teeth, they just grind and wear....and you'll be back to see the dealer, brother.
He was talking about his experience with them. He has serviced them for 14 yrs he has some basis for guesstimating it. Wasn't like its cast in stone. He was being honest about wear items he certainly didn't have to say anything. I have a way of getting them to tell me the truth about things.
I'll keep an eye on the tension springs. Gears need to mesh properly , no doubt about it. He said the replacements are metal/alloy , not the originals. I'll take his word.
It's good to talk to people that have had them awhile they know the quirks. So thanks!
Oh' I'm not going to the dealer for service unless its under warranty. I grew up on a farm built a couple engines fixed a couple things over the years. My tractor and backhoe never seen a dealer either. I prefer my own work. Plus you learn what is where and why.
I'm the cheapest mechanic I know. :wink: