My new 1930 2-dr sedan

[atch]

Next question: I have some 80W 90 lube left over from the last time I rebuilt a 3rd member.

Can (or should) I use this in my Model A transmission and/or 3rd member? This would be to top off, not replace.

Note: yes, I've watched Paul Shinn's video on this very topic (thank you @P.S.). I'm not asking for anyone to refute his advice. I'm leaving in two days for a weekend trip that will probably accumulate 800 - 900 miles. The transmission is a half inch or so lower than overflowing. I'm just wondering if I should use what I've got to top it off and replace it when I get back home or leave it alone. There's really no opportunity to replace the lube before I leave.

Note that I'll be checking the rear end lube tomorrow so same question there if it's low.

Another note: I thought that putting @ and then a username sent a notice to said user; like most other message boards do. I guess that's my mistake. I hope you see this Paul.