Well, Ive order pressure gauges and flow tester. Just got my orginal Case 2390 Service manual. Hopefully next week I can start formally diagnosing.
For anyone considering benefit of original Case Service Manual-GET IT!
I paid almost $300 for mine(ouch!) but it looks like it will be worth every penny. Over 1400 pages and lots of diagnostic information with pictures.
Manual spells out all the procedures for flow and pressure testing to specifcally diagnose trouble spot.
Just from reviewing the service manual-I'm pretty sure I've toasted my C-1 piston and likely the C1 clutch plates due to a stuck C-1 spool valve. The damage was probably done when the tractor would stall after warm up. If Tractor stalls when you engage clutch -STOP and check the spools-Specifcally C1. Otherwise you are guaranteeing to self destruct the clutch.
Just waiting for the gauges to come in to confirm.
The rear split doesn't look like it will be that difficult(famous last words)-Step by step instructions in the manual.
If you expect to work on one of these tractors, you will need at least $1000 worth of manauls and gauges in additon to your very complete tool collection.
It looks like I'll also have to fab up some splitting stands.
Rebuilding the power shift tranmission doesn't look that bad either, especially if damage is limited to C1 clutch plates and piston seals.