Shivering truck at 35-45…

I can’t confirm my truck is doing this but I’m 50% sure the truck has some weird shivering when I reach 35 and now 45mph.I don’t think it shivers going down hill but definetly more suspicious when I go uphill at 35mph.It feels like the road has bumps andthe feeling is deep under my seat or so it seems.I’m fairly confident this only happens when I’m pressing the pedal because I have coasted the truck over 35-45 and it doesn’t seem to act this way when I do that.I am finding consistent shivering on this part of my street where I drive uphill at exactly 35mph.I have tried several hills at 35 mph and I find this sometimes happens and sometimes it doesn’t.

Ok so putting the pieces together on this issue.The truck doesn’t seem to give this symptom when I coast at35-45 or when I drive downhill at 35-45.Doesnt coasting still cycle threw the transmission if it does then I’m assuming it’s not a transmission.Can this be a fuel issue?Or what about spark plug issue.If it was a spark plug issue I think I would have plenty of other symptoms.The only changes I have done to this truck is getting a coolant flush.
2010 TRD

 

I’ve had similar vibrations. Some possible culprits: carrier bearing and u joints.

 

Does the vibration almost feel like a HUM and it transmits right under the driver seat I think.It’s barely noticeable but let’s you know to let off the gas in which it stops.

How do I check if the carrier barring is bad?.I’m going to comb threw my whole drivetrain tomorrow.

 

Sounds like the carrier bearing

 

People seem to hover over the slip joint or cv.But how can this it be possible that I feel nothing when coasting this truck at high speeds downhill.I am fortunate to live on the side of a mountain and there is a long residential street to coast down.I would imagine these systems will be turning.

 

They’re not under much stress when coasting, which is why you may only feel this under acceleration.