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- #21
For the collective...
While I still have a long way to go getting her running as well as I would like her to, this particular issue proved to be driveline related (you called it jonheld !) .
I went through almost all of the engine recommendations above and was about ready to give up and have her towed off to a professional when I circled back to the driveline idea as a simple last measure before calling the truck.
Pulling the front DS did nothing but after reinstalling that and pulling the rear DS... the shudder and noise went away.
I went to the Tom Woods "Tech information " page and spent a couple of hours pouring through everything there. The short piece about diagnosing DS vibrations had a description nearly identical to what I was seeing in my 80.
If you have not visited that page - it is full of great info about drivelines.
4xshaft.com
I did 3 things to get her lined up better.
1. The rear driveshaft had evidence of prior work including a huge ugly weight welded on one end, so I took it to have it balanced (Heavy Fleet in Manassas, VA did the work). The tech there told me that it had a lot of run out that they worked to counter.
2. The downward angle on the center diff output flange seemed excessive (3.6*) so I replaced the transmission mount with a new OEM unit. That brought the angle back up to 0.7*.
3. When I bought the 80 it had a 3.5" OME HD lift on it (that was rendering closer to 4.5" of lift) and I did not like how tippy it felt so I replaced the springs with 2.5" medium duty ones. The PO did have the caster correction radius arm bushings up front but did nothing on the rear. The rear pinion angle looked pretty high so I picked up a set of ARB UCAs and got it down to close to level.
With all of that done the hard shudder is pretty much gone. Like I said - I still have work to do on getting the engine running more smoothly but this was a big win.
Thanks again to everyone who kicked in with recommendations.
While I still have a long way to go getting her running as well as I would like her to, this particular issue proved to be driveline related (you called it jonheld !) .
I went through almost all of the engine recommendations above and was about ready to give up and have her towed off to a professional when I circled back to the driveline idea as a simple last measure before calling the truck.
Pulling the front DS did nothing but after reinstalling that and pulling the rear DS... the shudder and noise went away.
I went to the Tom Woods "Tech information " page and spent a couple of hours pouring through everything there. The short piece about diagnosing DS vibrations had a description nearly identical to what I was seeing in my 80.
If you have not visited that page - it is full of great info about drivelines.
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4xshaft.com
I did 3 things to get her lined up better.
1. The rear driveshaft had evidence of prior work including a huge ugly weight welded on one end, so I took it to have it balanced (Heavy Fleet in Manassas, VA did the work). The tech there told me that it had a lot of run out that they worked to counter.
2. The downward angle on the center diff output flange seemed excessive (3.6*) so I replaced the transmission mount with a new OEM unit. That brought the angle back up to 0.7*.
3. When I bought the 80 it had a 3.5" OME HD lift on it (that was rendering closer to 4.5" of lift) and I did not like how tippy it felt so I replaced the springs with 2.5" medium duty ones. The PO did have the caster correction radius arm bushings up front but did nothing on the rear. The rear pinion angle looked pretty high so I picked up a set of ARB UCAs and got it down to close to level.
With all of that done the hard shudder is pretty much gone. Like I said - I still have work to do on getting the engine running more smoothly but this was a big win.
Thanks again to everyone who kicked in with recommendations.
