Bcart1983 Posted August 22, 2018 Share Posted August 22, 2018 Hello All, I am new to trucking, purchased my first Mack Rd688s last september, havent had any issues til recently. Whether im loaded or unloaded, my truck does not want to accelerate. It eventually does, but it takes it a while. My Rpms shoot up,but the truck will not move. Even when i try to take off in 3rd if acts like im loaded with 20 tons. I replaced fuel filters, checked transmission fluid, all is good there. Even my shifts points are different, I was shifting around 1100-1200 now I shift around 14-1500, any sugesstions on what could be wrong? 9 speed Eaton fuller, E350 engine. Quote Link to comment https://www.bigmacktrucks.com/topic/54087-acceleration-issues/ Share on other sites More sharing options...
Mackpro Posted August 22, 2018 Share Posted August 22, 2018 My fist thought Is clutch sliping. Does the clutch have any free travel at the pedal 1 Quote Link to comment https://www.bigmacktrucks.com/topic/54087-acceleration-issues/#findComment-404612 Share on other sites More sharing options...
Bcart1983 Posted August 22, 2018 Author Share Posted August 22, 2018 No free play, it still feels pretty tight all the way to the floor, on another note all the gears have been grinding at a dead stop. Does that sound like the clutch? Quote Link to comment https://www.bigmacktrucks.com/topic/54087-acceleration-issues/#findComment-404616 Share on other sites More sharing options...
RobM626 Posted August 22, 2018 Share Posted August 22, 2018 Sounds like clutch to me too.... out of curiousity, when you say you were shifting at 11-1200. Do you mean upshifting or down shifting? 1 Quote Link to comment https://www.bigmacktrucks.com/topic/54087-acceleration-issues/#findComment-404640 Share on other sites More sharing options...
fjh Posted August 22, 2018 Share Posted August 22, 2018 Yup me too how ever he should be smelling the un mistakable smell of heated clutch/brakes Quote Link to comment https://www.bigmacktrucks.com/topic/54087-acceleration-issues/#findComment-404652 Share on other sites More sharing options...
RobM626 Posted August 22, 2018 Share Posted August 22, 2018 Sounds kinda like the clutch is burning up from starting in too high of a gear and shifting and the wrong rpms. Quote Link to comment https://www.bigmacktrucks.com/topic/54087-acceleration-issues/#findComment-404660 Share on other sites More sharing options...
Bcart1983 Posted August 22, 2018 Author Share Posted August 22, 2018 So, I went ahead and took it to the shop today, and you guys are correct, it was the clutch.....BUT luckily it was just out of adjustment, big time, He said I got lucky, because it could of burnt it up. Preciate the feedback! After he adjusted it, I felt like i had to relearn how to drive the dang thing. It died on me 3x. Quote Link to comment https://www.bigmacktrucks.com/topic/54087-acceleration-issues/#findComment-404674 Share on other sites More sharing options...
RobM626 Posted August 22, 2018 Share Posted August 22, 2018 1 hour ago, Bcart1983 said: So, I went ahead and took it to the shop today, and you guys are correct, it was the clutch.....BUT luckily it was just out of adjustment, big time, He said I got lucky, because it could of burnt it up. Preciate the feedback! After he adjusted it, I felt like i had to relearn how to drive the dang thing. It died on me 3x. Just go nice and easy. Don’t start in to high of a gear espcially when you’re loaded. And pay attention to your rpms when pulling don’t fall below like 1100. Quote Link to comment https://www.bigmacktrucks.com/topic/54087-acceleration-issues/#findComment-404675 Share on other sites More sharing options...
Mack Technician Posted August 26, 2018 Share Posted August 26, 2018 It’s never going to happen to you, but in case. Had a customer come in one day after riding a slipping clutch for hours. I heard a “tist tist tist tist” coming from under cab. It was A/C water jumping off the bellhousing. I waited a while for it to cool, but naturally customer is “losing money”. Popped the clutch access bolts, flipped the driver over and slapped the plate to knock it off. Plate fell off and poured hot liquified grease onto my hand, interior mess had melted as fluid into belly of bell. It was on me for a few seconds and when I hit it with my other hand it went from tar black goo to pinkish-white, skin came off. Moral=Tell customer he needs to walk over to McDonalds and hand him a newspaper. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/54087-acceleration-issues/#findComment-404869 Share on other sites More sharing options...
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