Is there a plug under the spot where the hose connects on that black tank? It can overflow into that but unable to return it with the hose on the top. If not get a different tank
They can, the hard part is finding the key that will work on both, they have the grooves in different places. You can also swap out to a later column if your floor shift and change the locks if you can find an xj from 93-95 iirc these use a single double cut key
Trans has been built, mated to the engine and stuffed into the car, full 3 in exhaust with 3.5 headers, front and rear suspension has been gone thru. E brake fixed, other things replaced. So close to the end, yet it feels so far away
More then likely it's brake fluid from the clutch cylinder,the biggest issue is it ruins the plastic fuse box, they do sell new pins for it and there is a write up or two that explains how to do it.
Do you have voltage at the flashers relays? You state 3 volts, where did you Check it at? Is this a 4.0 manual?
Check the intake bolts for tightness, any vacuum leaks? Performed tps adjustment? Does it do it with the cable detacted?
Should be able to press here, but the cluster you want to use is an 86 and there was no 4.0 not sure if that cluster will work as the values might be different. You can swap speedo between them