Trans and motor mount replacement question

[Tommy Z]

Planning on replacing the worn out trans and motor mounts in my 79' SC this weekend and it's my first time doing it. Car will be on jack stands and wondering about where exactly I should locate my floor jack to properly support the engine and tranny for swap. For the tranny mounts, do I want to have the support in the center of the cross member or on the actual transmission itself? Is the bottom of the sump plate the center of gravity for the engine or is someplace else Photos would be greatly appreciated if anyone has any from this project and as always suggestions are always appreciated.

[scotricker]

Don't forget the shifter linkage, that might be an issue if you lower it too much.

The transmission should be easy, put the jack under the center of the support and do those 2.

For the engine, try doing each side separately, you've got a bunch of weight, and dont want surprises. Put the jack on the center sump area, and loosen one bolt, just enough , and change that side, then go at the other one.

That engine is heavy, so maybe a bigger jack, like an atv jack or transmission jack would be more secure.

[47silver]

Put some rolled newspaper on the jack to help protect metal

[Tommy Z]

Originally Posted by scotricker

Don't forget the shifter linkage, that might be an issue if you lower it too much.

The transmission should be easy, put the jack under the center of the support and do those 2.

For the engine, try doing each side separately, you've got a bunch of weight, and dont want surprises. Put the jack on the center sump area, and loosen one bolt, just enough , and change that side, then go at the other one.

That engine is heavy, so maybe a bigger jack, like an atv jack or transmission jack would be more secure.

Thanks Scott, regarding your warning about the linkage. Do you mean I should disconnect the linkage in case I lower the engine and trans too far? My understanding is I'm not actually lowering either, rather supporting them in place as I remove and replace each mount one at a time. Is that correct? I'm hoping they don't shift a MM while I do this.

[Tommy Z]

Originally Posted by 47silver

Put some rolled newspaper on the jack to help protect metal

TSilver, that's what I use the original Chiltons manual I first bought for.

[proporsche]

whatever happened to the favorite yellow pages;-)))))all gone.....

Ivan

[Ian Comerford]

If you have time it’s worth getting some penetrating oil into the threads of the main bolt through each of the engine mounts. If they are tight you will probably break the right hand side engine cross member end, it’s susceptible to being rotated off the end of the cross member if the threads are stuck. The right side is more likely to break than the left due to the construct. Quite a few people have experienced this and I am one of them. Hope this makes sense.

[scotricker]

Originally Posted by Tommy Z

Thanks Scott, regarding your warning about the linkage. Do you mean I should disconnect the linkage in case I lower the engine and trans too far? My understanding is I'm not actually lowering either, rather supporting them in place as I remove and replace each mount one at a time. Is that correct? I'm hoping they don't shift a MM while I do this.

OK then one at a time, but don't let the trans drop any more than what you need to slide the mount out. The rubber piece is between the crossmenber and the car.

The engine will want to drop down a bit but you have more to work with at that end, still be careful , oil lines and such.

[Walt Fricke]

1) surely you have a floor jack. You can do with any number of measures, but if you work on your car you need a floor jack for all number of jobs.
2) The CG of the engine/transmission is toward the flywheel end of the engine, where there is a convenient nub in the case casting. The engine itself balances on the center sump plate (on the earlier engines which have one). But commentators make a good point that you can do this end for end, so you only need to support the transmission out toward its end, and the engine the same. Some of us routinely jack up our cars to get both rear tires off the ground, or for other work, from the rear of the engine, right up against the motor mount - or using it. That will work fine for the rear. You'll have to do this to get the rear of the car up in the air far enough to get working room, and to get jack stands in on both torsion bar end caps or whatnot.

3) With the car up high enough to work, you just need to keep the tranny/engine up tight. The rear mounts extract out the top, and the tranny mounts from the bottom.

4) Good point about twisting the end of the engine cross mount off, or rather, avoiding that. Early on the long mount bolts went through the tube in the mound, and you used a nut on the bottom, so you could counter hold the bolt while you loosened the nut, or - because more convenient - the other way around despite the commandment always to tighten a nut and not a bolt. I know later SCs had threads in the tube (so hard to figure out how to counter hold - vice grips maybe?), but don't know when the change happened. Obvious, though.