I'm thinking the center driveshaft carrier bearing is an issue. They also thing the pinion angle is off when the 5er is on it. But that still doesn't help with the lack of power to move the camper.
As with the OP we are looking into the 38FLFS. Not sure yet if the Pinnacle or the Eagle. I like certain things in each. Probably going to go with the Eagle because of the cost difference.
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2016 Pinnacle 36REQS
2022 Ford F-450 6.7 4x4 CC LB Dually
Mike & Chelle, My kids when they decide to go with us.
I would take the Ford to the dealer with the trailer, let the service manager experience the shudder, somehow they will get to the bottom of the issue, it too could be a torque converter in the transmission
I walked through a Pinnacle 38FLFS at the RV show last week. It was my favorite of the large 5'ers. If I were looking for a retirement home, that would have been the one.
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Becky, Bob and Taylie & Bode
2009 Silverado 2500HD Duramax/Allison
2014 Heartland Sundance XLT 245RL
His and Hers Polaris 570 Touring ATV's
2018 Polaris General 1000
I almost pulled the trigger on a 3/4 ton duramax until I found out it had a max payload of 2420 lbs. A little light duty for a pinnacle IMHO. Have you had any problems towing?
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2015 Jayco 27DSRL (Sold and shopping for new 5er)
2016 Little Guy CIRRUS 800 Truck Camper
2015 GMC SLT 3500 Duramax Crew Cab, SRW
KYcamper, I have a 2011 2500 single rear wheel drive 4X4 duramax. I weighed all of my camping gear to make sure I would not exceed the payload capacity. I have a Pinnacle 36KTPS and it pulls great and very stable compared to the 25 foot travel trailer I used to pull. The pin weight is 20% of the total trailer weight so if you went to the trailers max gross weight you would exceed the payload weight for the truck. With the trailer fully loaded the truck is still level. I even had to raise the pin box one bolt hole to get the trailer level while hooked up. I am very happy with the performance.