It's been something like 20 years since I had both the engine and gearbox out of the car at the same time. I had pulled the gearbox and events were such that I skipped an event with my car to help someone sort their S2000 so being summer break (no runs in Vegas when it's 110 out) I pulled the motor to re-ring it and put a new cam in.
I'm getting ready to put everything back and it's way easier to bolt it all together out of the car but is it a headache to install them as a unit??

It's been a while and I think we did this one but can't remember.

Tom

The difficulty is clearance below the vehicle, if you have a pit beneath the car that will allow enough clearance that you can dip the engine & box assembly to such a degree that you are almost dropping them in nose first (gearbox nose) then it's pretty easy.

But if you are doing it without a pit or without the car high enough in the air then the nose of the gearbox will hit the ground before you can get enough angle to have the sump clear the radiator support panel top.

I recently removed an engine a gearbox from a wreck as a complete unit (without a pit) and there was a bit of scraping and scratching against the vehicle and ground. I think removing it as one piece can be easy enough done (with care) but the other way round might be a bit difficult with out a pit.

Lets see what other guys have to say, there might be a bit of a trick to it.

I have done it with the car on ramps and stands. As Chris suggested, there is not much room to swing the engine/gearbox. I find it easier to just install them seperately...

Yes. I've always thought it was easier to install the engine and tranny as a unit. Less crawling around under the car. Less crawling is getting more important as time goes on. Seems like the floor is getting further away as I get older...

i install my ca18det and ca box as a unit as long as you take it easy its not too hard makes it abit easier if you get a mate to help
it would be a heap easier to install an a series with the box attached

I have only installed them seperately once and it was a lesson learned. Every other time i have done it with the car on stands and it has been a breeze.

I like to remove the engine crossmember and detach steering linkages from passenger side. Then put engine and gearbox on the crossmember with it lying on the shed floor. Do this underneath the engine lifting point if you are using a block and tackle. Then roll the car forward and lift the front of the car over the top of the engine using block and tackle. Once engine is aligned to its resting place in the engine bay, attach the lifting chain to engine and gearbox through the engine bay and lift into place.
While lifting engine put a trolley jack under gearbox crossmember to lift the gearbox. Use a rope through shifter hole to pull up gearbox onto jack.

This is the best way to do a ca18 install without an engineering degree.

I've done it both ways, & the advantage of lining up the clutch & being able to get to all the bolts properly outweighs the extra care needed. I usually put the REAR wheels up on wheel ramps or stands, so the back of the box doesn't have to go down too far to go in. It's a bit of a squeeze doing up the g/box crossmember bolts, but really easy for doing up the tailshaft bolts. All the bolts in the engine bay can be done up from the top, or you could just remove the wheel ramps.

I just had the pleasure of installing both the motor & trans then pulling & reinstalling the motor due 3 leaking freeze plugs & a oil pan gasket that leaked like a sieve. I originally had the motor in first then installed the trans which went in pretty well, minor wiggling to align the splines.

2nd time around I left the trans in & gambled, pulled the motor, reinstalled it - everything went smoothly. Aligned itself quite easily but I think others are right unless theres lots of room under the car its more difficult.

If I could get a complete 4AGE and W58 gearbox in and out as a unit without scratching anything up, I'm pretty sure you'll be able to do it with an A series...