Transmission pan detent spring recess measurement

I have a spare pan in the shop somewhere, I’ll be there a bit later if nobody chimes in

 

I had a little "simulator" piece made to hold the springs with the gearbox pan off (for my 1978 ex-308), and measured it at .49" (although it's probably 12.5 mm deep):

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Are you doing something similar, or making a whole new pan, or doing something even crazier?

 

If you wanna be very lazy, I saved the pan to chop it up to Make the tool, you can cut it and use it and just give it back to me whenever you’re finished

 

I need to take some measurements of that American flag thing you’ve got, rear bumper, and front

 

For what it's worth, I created a CAD file of a small device that holds the detent springs in place in the transmission while the pan is off. It's available here: https://www.thingiverse.com/thing:6699899

Based on my measurements, the hole in the original question was approx 13mm, although it would probably work at 12.5mm as well.

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I found my detente balls were 8mm and no chrome showing plus prior owner had sooo much silicon sealant in these area.
5/16" chrome ones at Home Depot are 7.9mm and work better now

Are you adjusting the shifting system?

 

My 1-R detent ball moved freely in its bore but would not drop out of the end of the bore bushing so I left it in there while doing a recent gasket replacement. The 2-3 ball was slightly larger than the 4-5 ball, and it looked to me like someone had reamed out the 2-3 bore bushing at some point, which might explain why they put a slightly larger ball in there. I had ordered spare balls and springs in case they were needed, but ended up sticking the previous parts back in.

Here's a pic showing my 328's 22 year old gasket in the area around the detents:

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Has anyone seen this deformation/tearing on the gasket before? It looks like over time, gear oil trapped inside the bores of the R-1 and 2-3 detents squirts out the bottom when the balls move down, and it bulges/tears the gasket in that area. The 4-5 detent has an additional spacer that seals off the bottom of its bore, and the gasket looks fine in that area.

I did notice a change in shift feel with a new gasket and different gear oil (Redline MTL), where there is now a light "drag" feel in the shifter in the 1-R and 2-3 gates, I assume because the new gasket is sealing off the bottom of the detent holes and gear oil is trapped in the bores and creating some resistance when the balls need to move. It may be the normal feel and I had just gotten used to the way it was before with the torn gasket.