M90>ZF22 & electric fan conversion

[v8volvo]

Welcome to the board!

That plan doesn't sound ridiculous to me at all. I was never a fan of automatic transmissions until I started driving a 740 TD with D24T and ZF 4HP22. The ZF is a fantastic transmission that is a perfect match for the power delivery of the D24T. I like them with a manual but I like the automatic even more.

It sounds like you are starting with a good parts supply for this if you already took a ZF out of another car. As far as I remember (but can confirm this week for you), the flexplate goes right onto the crankshaft, no spacers or shims. However, there is a large "washer" carrying all of the flexplate-to-crank bolts, and the bolts for the flexplate are definitely shorter than the M/T flywheel bolts since the flexplate is thinner. You will want the correct length bolts. Greenbook manuals might even give the length spec for them, greenbooks are usually very good about that. You could probably source them from another vehicle such as an Audi, or order new hardware if needed. I'm not sure what would happen if you tried to use the bolts from the flywheel that are too long -- maybe it wouldn't matter much since they are open to the internals of the engine as I recall?

No pilot bushing needed with the automatic, in fact you will need to REMOVE the existing manual trans pilot bearing from the back of the crankshaft before assembling with the automatic, because the torque converter snout goes where the pilot bearing used to be (same outer diameter).

The small stuff won't be hard to figure out, the parts that really matter are things you presumably already have like trans mount, shift selector, driveshaft front half, and the trans/converter/flexplate. Some bellhousing bolts may be different length as well but you'll figure it out with them. Any questions you have along the way just ask here and we'll do our best to help.

Best place for a fan thermoswitch would be in the radiator itself, rather than in any hose. Factory Volvo location (as seen on the 1992+ cars that only had e-fans from the factory) is on the passenger side near the top. I would just use one of those if it were me. I am guessing they run similar temps but I think it says the settings on the switch.

You could also put it in the lower hose but I think you might want lower temp settings for running it there. It's OK that that's where the T-stat is. At any engine temp where you might possibly need the fan to come on, the T-stat will already be wide open so it won't affect anything. If the T-stat is closed, then that's because the engine is cool, thus no need for fan operation anyway.

That said, the factory mechanical viscous fan does work fine. They are noisy though.