I've have a super loud tranny/drivetrain noise when the truck is really working hard, pulling the backhoe, or Monarc Pass in Co. with a loaded hunting trailer (what it was doing when this started last fall). Have to be making 30 or so lbs. of boost. Doesn't matter if in 5th or 4th, same deal. You don't know if you're gonna make it another 100 feet.

No load, drive normal, no problem.

Well Peter sent me a new ConO, pilot shaft bearing, and throwout bearing. I had convinced myself that @ 150k the pilotshaft bearing was bad, causing the input shaft bearing to start to fail.

If not the possibility listed above I expected to find some other easy to spot issues when I tore into things.

Well, I pulled it down today, the pilot shaft bearing is still good at 150k still has grease, could reuse the stock clutch assembly if I needed to. Everything looks great, the input shaft is tight with no undue slop.

I haven't pulled down the tailshaft to check things back there yet, so I may find a problem that I can fix yet. I haven't had any issues with 5th gear coming off, still the factory nut. Oh, the front u-joint was a little rough on one axis.

So, if anyone has any advise on what to check, I'm all ears (eyes?).

 

Check and see how much freeplay you have in the mainshaft and countershaft (front to back play)

easy to do once you've removed either of the side covers.

 

Lil Mule, that's on the list. I'll check that out tomorrow. If the tranny checks out I'm wondering if the transfer case could be at fault.

BTW, did you make it to Dan Eoff's last week for the Chuckwagon races?

 

Things I've checked; the snapring is still in place and doing fine on the transfer case output shaft.

I checked the 5th gear nut, doesn't appeared to have moved in 150,000 miles, all the bolts are still tight on the plate behind 5th gear.

Also checked the clearances at the backend of the mainshaft and countershaft.

mainshaft; .001

countershaft .003

No debris in the bottom of the trans case, just a small amount of metal crud on the sidecover magnet.

Checked the rearend, everything looks good, no metal on the drainplug magnet, carrier bolts tight, look great in there.

I'm starting to wonder if the front u-joint with its small amount of roughness on one axis could be the problem when things are under load. Naw, that can't be it, to much noise when it's acting up.

I have for the most part treated this transmission with care, shifting it like a truck tranny, not a sports car. Kept rpm up when in 5th, and when necessary dropped down to 4th rather than using 5th at 1500rpm.

I'm on the verge of installing the new ConO, putting it back together with a new u-joint and driving on.

Or, packing the tranny up and shipping it Standard Transmission for a mainshaft and general freshing up.

Still open to suggestions though.

Thanks RJR