vibration/rattle?

[80' 427]

I have been gearing up for moab for about 2 months with my 84 K-10 lwb. It is fairly stock with a 2.5" superlift, 33" truxs, trutrac/detroit in the 10 bolts (I know), mild 350/700/208. I called offroad design to get a swaybar disconnect and ask what else I needed to best avoid problems. So now I have a steering box brace, disconnects, and greasable shackles, with longer shocks and axles in the mail as we speak(great people by the way). Still need to install the shackles. So Stephen tells me to go try my truck on the most steep hill I could find and see if it stalled. Well saturday I went up the hill I have in my pasture. The hill is grass covered and about 42-45 deg depending on the part. With minimal spininng it when right up and it even has a holley ta. While pulling the hill is made a growl/vibration that sounded like it was from the front driveshaft. It has never made this noise before but I don't go up steep stuff much here. Again last night I was hauling a load of rocks for the wife up a steeper hill and the noise again. Could it be I am getting some spring wind up and it is changing the u-joint angle? All the u-joint feel great. I just don't want to blow up anying and have to fix it in the middle of BFE if I don't have too. Sorry this is long but I wanted you to have all the specs.

Thanks

 

[chevy wrangler]

check your gears

 

[80' 427]

Now that I think about it, the only time it does it is in 4lo.

 

[resurrected_jimmy]

check the slip yoke on your front driveshaft. The "growl" you mention makes me think the splines may be stripping

 

[chevy wrangler]

i thought that too but found out it was my spider gears

 

[4xcrazy]

check your transmission mount, broke mine in Moab last year, it drops the whole unit down low enough that when you are loading up the driveline, but unloading weight from the front end, it pushes the driveshaft/transmission downward some ,,,,

the grinding sound in mine was the CV part of the front driveshaft rubbing the crossmember.

Mine first started doing this when i highcentered pretty badly and slightly bent the crossmember some, then as you mentioned, climbing hills only, it would make that horrible grinding noise...it is annoying

 

[80' 427]

I will check the mount. Sounds most likely, no spiders trutrac, splines look good.

 

[rivermtnman]

I'll 2nd the mount. Mines done the same for the past year. I finally figured out the cv joint was rubbing the bent crossmember and figured I would run across another crossmember to replace it someday. I was working on it yesterday and drove it over to the garage without the tranny hump and noticed when I would start up a hill the tranny looked like it was coming up or twisting on the drivers side a couple of inches. With further inspection the mount is shot.

 

[wildmouse216]

I bent my transmission crossmember up so bad that engine tilted down and the harmonic balancer was rubbing the front crossmember and making a grinding noise. That was a really bad high center with the full weight of the truck on that crossmember.

I thought I was the only one to strip the splines in a driveshaft slipyoke.

 

[80' 427]

And the answer? Drum roll please...............




























Transmission/transfercase mounts. I couldn't have slipped a playing card in between the drive shaft and the crossmember. I installed new mounts and everything should be good to go for moab. Man these trucks are easy to work on. Thanks for your help guys.