Vibration on uphill/hard acceleration??

[ctjkelley]

I recently put a RE 4.5 front and 3.5 in rear. Ford 8.8 rear axle. My drive shaft angle is pretty good, since the lift if I accelerate hard or if on crawling a steep incline there is a thumping sound that would mimic the sound of the drive shaft hitting the floor pan, any ideas on what this could be. Thanks

 

[Mach2nh]

Hows the trans mount?

 

[ctjkelley]

Good

 

[WB9YZU]

There are a few things which would cause that.

Engine/Tranny mounts.

Incorrect drive line angles.

Loose spring perches/broken spring eye bolt (had that one happen, took forever to find).

How about the simple one: Is the tail pipe banging on the rear shackle?

-Ron

 

[ctjkelley]

I will check the list you gave me, thanks for that by the way!! As far the exhaust goes I have a turn down right out of the muffler, and unless it's just a coincidence that a engine or tranny mount is loose post lift, this sound/noise was not there pre lift. It's very frustrating trying to find I do know that, would the u-joints have a hand in this by chance? And I guess this would be a dumb question bit how can I check the drive line angle to make sure it's proper? Thanks again for all of the help and ideas!!

 

[GordoSmasho]

It is always more helpful to put up info about your rig like year trans and such. But if what your profile says is right you have a 1998. I have a 97 auto with an 8.8. I had the same type of sound after I put in my sye. It ended up being the cv joint banging against the plastic bracket that holds the rear o2 sensors connector. The 8.8 is offset to the passenger side a bit and it was just enough to cause a clearance issue with that bracket so I cut it off. It was very loud in the cab.

Just a thought.

 

[ctjkelley]

Update in issue, went and did some wheeling yesterday afternoon. It sound is still there on steep grades however it seems to go away when using 4wheel drive. 2wheel drive seems to be the only time it does it. And yes it is a 98 sport.

 

[Flyfisher]

My money is on the transmission mount on the cross member. Had that exact symptom some time ago.

 

[ctjkelley]

Was yours loose or broken?

 

[Flyfisher]

Mine was shot...the rubber was toast.