Transmission acting up 2017 T680 Whats happening?

Just posting this to see if anyone has encountered this before and or can give me a better understanding of what's going on with my rig. I drive a 2017 T680 Kenworth single axle with Eaton fuller transmission.

Coming home from a trip one evening I was in a slight hill climb doing 55mph with cruise control on. Randomly it acted as if someone and basically jumped in front of me cutting power however when I took over I was able to rev the RPMs as if I was in neutral although the truck was still showing 10th, The truck coasted a few seconds then downshifted to 9th then I was fine back up to 10th and figured it was just a hiccup.

Now after a weekend off I had got back to work but felt like I was noticing a shaking/vibrating of the truck. I questioned myself thinking I was just feeling every bump of the road for whatever reason but it wasn't the case as what I was feeling was getting worse. Took it to a shop 3 times but they were unable to see what I was feeling and I ran the truck for about a week up until yesterday.

Yesterday on another trip the same issue happens again on flat land. I'm in 10th gear and it lets go where I'm able to rev the rpms as if I'm in neutral. The truck regains itself although a few minutes later it lets go a few more times and then I was good for 50 miles before yet another happened and 150 miles after that was totally fine. Tonight became the big issue.... It was constantly doing this in 10th gear although when I was keeping it in 9th there wasn't any issues. Also each time it's kicking me out of 10th gear/losing power in 10th gear with no grab I can hear the low beeps (what I call the thinking beeps) that it does when its shifting gears.

Just wondering if this is what's causing my rig to vibrate/shake I feel it all in my seat and not on the steering wheel. They've told me my driveshaft is fine.

 

Well I'm not sure that would explain the shaking/vibrating of the truck. I was thinking driveshaft at first but mechanics were saying it was fine. I understand what you're talking about though but I don't believe it applies. I'm talking about a full let go.... Even when I'm not maxed out on my speed and both on a climb/downhill.

 

Well funny enough I did have one mechanic tell me my slip yoke is a little loose but when I got it back to the home terminal they all had said it was fine even after 2 visits. No transmission fault however. One night when I turned it on (about maybe a few days after I had the first instance of it basically doing nothing in 10th) it gave me a seek service transmission fault warning, but after turning the truck off for a few minutes and turning it back on it went away and I was able to run. However still with noticeable shaking. The shaking is only at speeds of 50mph plus and I've not felt it Bob tailing at 45mph. I feel it pretty noticeable going down a hill at higher speeds of 60 to 70mph. And like stated above I only had this issue in 10th gear... When I was forcing it to 9th and climbing hills in anything other than 10th it wasn't having a problem. 10th seeming to be a faulty gear now. My last instance was having my 10th let go.... The truck did downshift to 9th and I was still able to do nothing.... So I came off an exit and about the time I hit 30mph the truck finally recollected itself and down shifted to the appropriate gear and giving me throttle back.

 

Company truck. You're right.... And its gonna be serviced now because I dropped it for another truck until it gets fixed. Was just getting more insight of what's wrong. Trying to also make sure that's potentially where I was getting the shaking from. Ill hope when they fix it the extra shaking goes away.

 

I can agree with that! They test drove it but you know every truck has its own feel to it. Some trucks of the same model shake in their own ways but being in this thing for 10 months I can tell you that a few weeks ago it didn't feel like this and they're not gonna see what I see haha.