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75 Highboy when I get on throttle I hear a
“ clunk” noise Checked out differential Dana 60 all good , pattern good, back lash. Driveshaft good. This was checked out by professional shop. New AOD transmission new driveshaft.
Did these truck have that slop “clunk” noise when get on off the throttle aggressively?
Any ideas or answer to my last question?
Will have the transfer case checked out by
professional shop this week.
I've never noticed anything like that. U joints or spline slop in the shaft between the transmission and transfer case would do it. check the mounts on the transfer case too they wear out.
I just replaced the rear shaft joints on my 205, and it still has a little clunk on power transmission. There is little play in the transfer case output shaft yoke, and I am sure the mounts are not helping at all.
I've never noticed anything like that. U joints or spline slop in the shaft between the transmission and transfer case would do it. check the mounts on the transfer case too they wear out.
mounts are new everting is tight. Spline in driveshaft check out good.
I’m down to mounting a go pro a underneath to see what’s up.
transfer case has never been rebuilt , perhaps it’s time for freshening up?
Some Highboys have that brace from the case to the frame. Should I fab one up?
If you mounts are good the brace shouldn't be needed. I've never had one on any high boy including the one I have now and I've never had a problem.
Could your rear spring bushings be so wasted they're jumping when you put power to the axle ? they'd have to be bad to notice much.
just a thought to see if it's in the rear axle, does it do it as bad in 4 wheel drive ? if there's no change at all that would make me look from the transfer case forward.
If you mounts are good the brace shouldn't be needed. I've never had one on any high boy including the one I have now and I've never had a problem.
Could your rear spring bushings be so wasted they're jumping when you put power to the axle ? they'd have to be bad to notice much.
just a thought to see if it's in the rear axle, does it do it as bad in 4 wheel drive ? if there's no change at all that would make me look from the transfer case forward.
Thanks for your thoughts on the brace. Rear spring bushings were replaced when I built the truck.
Haventtried in four wheel drive.
Just running out of ideas.
Rebuild kit on the NP 205 isn’t bad. Maybe I’ll go that route. It leaks fluid thru seals it’s one major component I haven’t torn into yet.
I really feel like I need to tear into the np205. The differential mechanic did once over on the condition said everything checked out. U joint new,driveshaft splines good,rear spring bushings replaced during restoration.
Differential mechanic said there was slop in transfer case but he said take to transfer case guy get his opinion. It’s been awhile perhaps I will remove driveshaft myself check that slop. If I decide to rebuild , I do remember that np205 was not light in weight. LOL
Rebuilding the 205 is a fairly easy thing to do. I did mine this past October. Took one day (after work) to drop it and clean it up. Couple hours next day breaking it down. About 4 hours to rebuild. There are quite a few little needle bearings that can be a little tricky. Depending on which guide you use remember that some pics may show a Chevy version of the 205 (passenger side drop) so thinks will look bass ackwards!
Last edited by Shawner1974; May 12, 2020 at 10:50 AM.
Reason: Typo
I will likely rebuild mine at some point. There seemed to be a good bit of fine metallic flake in it when I did the output seal. I would hope this is from the bearings, and not the gears. From what I've gathered, if the gears are toast you're better off finding a new case as gears aren't cost efficient. That rebuild guide F250 posted is a good resource.
Are you certain when you hit the throttle that motor/trans twist is not making something contact? Not sure how you worked out the shifter on a AOD over the stock C6. It is tight at some points. Also, hedders can make contact as well.
If the NP205 needs a rebuild then do it, but don't make it a case of a solution looking for a problem...find the problem first.
Very nice truck....where is the fuel filler, tank? Love the blue/white paint scheme.
