NOS Corvette wing window gearbox internals and grease.

[Richard G.]

I recently acquired a NOS Corvette gearbox that was purchased new in 1970. I posted the backlash results and how I measured it in a prior posting. The gearbox would not rotate as I received it. I had to spray Aerokroil on the shafts and wait overnight before I could rotate the input the shaft. After I got it to turn I measured the backlash as received. The gearbox turned very hard. This posting is what the internals looked like after removing the cover and how it was taken apart and assembled. First I used a mill to remove the aluminum that was Peened over to retain the gearbox cover. this can be done with a file also. One could drill and tap the center of the peened area first if you want to but I did it this way to be sure the bolts were in the center of the cover hole.



Next the cover was pried loose with a screwdriver.



Be careful not to loose the beveled washer on the end of the shaft. It this case it stuck to the cover.



First glimpse of the internals.



Grease resembled honey that had dried out. It had no lubricity what so ever.
It stuck to everything more like glue than any type of lube.
The glue remnants reminded me of pine pitch more than it did anything else.



The NOS shaft with remnants of the lubrication.



The grease scrapped out onto the bench.



This "never used" 48 year old grease was more like old glue than grease.
The large gear was left in the gearbox case and was cleaned out using thinner and a brush.
Then the gearbox was drilled and tapped for a #12 machine screws to retain coner. Note; Some re-builders use 1/4 bolts.
Then was re-assembled using new white lithium grease.
The difference in the torque required to turn the gearbox was astounding.
I hated to dissemble a NOS gearbox but really had no choice if it was to rotate like designed.
Hope this helps.
Rick

[Gary B.]

Re: NOS Corvette wing window gearbox internals and grease.

Rick,

You might check with Vinnie Peters to see if this could become a tech article for the Restorer.

Gary

[Duke W.]

Re: NOS Corvette wing window gearbox internals and grease.

Agree... this would be a very good tech article for The Corvette Restorer.

Duke

[Gene M.]

Re: NOS Corvette wing window gearbox internals and grease.

Richard,
If you elongate the two drilled out holes in the steel plate so you can tighten up the gear center distance, the mesh will reduce the backlash and reduce the crank handle slop. The original gear backlash is excessive even if brand new. A small weld build up on the opposite side of the elongated holes will insure the plate does not move. I’ve performed this rework on all my cars so the vent window operation is better than when brand new. If the aluminum gear is chewed up a replacement is available. But I never had to resort to a replacement once I did the for mentioned modification since it puts the gears deeper in mesh. Use of a synthetic grease will out last it’s owner.

[Darryl D.]

Re: NOS Corvette wing window gearbox internals and grease.

Boy, I think I would have just taken the side cover off and filled it with some type of solvent and let it sit for a week or two and trying to turn the input or output shafts back and forth until it moved freely. Then I would have continued to flush it with some kind of cleaning solvent. That old grease would have to disappear at some point and let thing rotate.

[Richard G.]

Re: NOS Corvette wing window gearbox internals and grease.

Darryl
You know that just might have worked even leaving the cover in-place. Especially if one could have heated the solution. However I am happy with my solution even if I have two extra bolts. I am not sure they can be viewed with the door window down as I haven't assembled the doors yet.
Did you mean the low speed shaft cover?

It has to be removed and reinstalled using only upset aluminum. Not very confident this can be done reliability twice. Possibly it could be rotated and removed. I never saw the need but would be interesting. Anyone tried that method?
Rick

[Gene M.]

Re: NOS Corvette wing window gearbox internals and grease.

Peen over the aluminum casting to tighten up the steel plate in the housing is good to take some slop out too.