g741.org

it continues.
I have torn this 1/2 ton tranny down to every bit and am examining every surface, and taking measurements to determine wear and out of roundness.

For instance, on shafts, I’m comparing the surfaces where the bearing ride to an area on the shaft where there is no wear area.

Aside from a few gear teeth on the cluster having some pitting, the bearing surfaces inside the cluster look pretty decent. As does it’s shaft.

Mostly everything else looks pretty good.
Perfect? No, but not bad at all overall.

With the exception of this main shaft “nose” piece that rides inside the input shaft.

Its got some pitting. See pic. I took my calipers and measured and its a uniform diameter that is not scalloped or egg shaped. Its still very much round.

The pits are not raised. They seem to be a result of corrosion, eating at the surface, leaving inset craters like you see here. I have no way to accurately measure the depth of these pits, but I’ll take a guess at at least a few thousands deep

One opinion so far tells me this would NOT cause the “grrrrrrrring” or grumbling noises that Im experiencing while idling in neutral, foot off clutch.

But I’m skeptical. I remember the importance of this main shaft “nose” finish when I built my jeeps T90 Tranny and was told anything under a near perfect polished surface would lead to noises in operation.

I am thinking the same applies here?

I doubt that pitting there would equate to the grinding described and on the video/audio. You could polish that out with an emery cloth. I'd keep digging-there has to be something amiss in the internals to cause that grinding sound. Are there any synchros in that tranny? Just thinking out loud. I recall an old top cover in my Army days where the shift forks ended up being the culprit-one was bent just enough to create resistance when the gears were turning.
Gary

Well that may be the case where it really is t the issue.

The only other thing was “rattling” gears on the main shaft splines?

Would loose spline to gear tolerance add to the noise in my video?

I was thinking perhaps so.

When I took out the 1-2 and 3-direct gears, they had a bit of play on the main shaft splines
The other Tranny I had lying around yields very very tight gear to spline mating.

So I’m using them. They look better too

My old tranny gears fit rather loosely on the shaft but under load I would not think they'd make the grinding noise you have. Perhaps a close-close look at the actual gear-to-gear surfaces is the next step-mine are silky-smooth and not rough whatsoever.
Sorry I'm not more help but hopefully you'll figure it out.
Gary

I had a PM request asking about the outcome.

I also asked the same questions on the G503 board and in the end figured it was most likely the input
Bearing “nose” surface causing this.

Anyway. If anyone wants to see the tread on this, here is the link:


https://forums.g503.com/viewtopic.php?t=309276

Thanks all
On this forum for responding