Looking for info on the height of the 722.321 transmission as I'm contemplating swapping the one in my 86 300SDL that has a significant front seal leak and lots of upshift flaring for one rebuilt within 50,000mi and no leaks that I can get for $600-$700.

So, 2 questions:

What's the height, so I can calculate the clearance needed to pull from below in the driveway with ramps and jack stands?

If I choose this path, what's the best manner of maintaining drive shaft balance? Should I pull the donor driveshaft as well, or attempt to mark my current driveshaft for connection to the replacement transmission?

Thank you,

Paul

It may seem counter intuitive, but I'd like to suggest at least considering the notion of pulling the engine and transmission as a unit, swapping the transmission on the engine and putting the unit back in.

Wrestling with a heavy transmission under the car is a really ugly proposition and if you've got it high up in the air on jack stands, a potentially dangerous operation as well.

With the engine out of the car it's a heck of a lot easier to ensure that you've got the torque converter fully engaged before torquing things down and damaging something if it's not.

In doing my engine swap I've had the engine/transmission in and out many times and and it's now a 4 hours out and 5 hours in proposition working alone.

You will likely get opposing opinions, but at least consider this strategy to see if it might be a good way to go for you.

In addition it will give you the opportunity to do a good cleaning of the engine and engine bay and inspect many components that are hard to reach/see otherwise.

Driveshaft balance is not an issue, provided you don't separate the two halves. If you do, check for witness marks, or mark yourself to be completely safe. Definitely check the flex disks and the center bearing while you've got things apart.

And for safety, consider building some cribs instead of using ramps and jack stands - cheap life insurance.

__________________
Current Stable

• 380SL (diesel)
• Corvette C5
• Manx
• Baja Bug
• F350 Powerstroke
• Auburn Boattail Speedster replica

I've replaced MB trannies by myself with my chopstick arms and a floor jack. I don't have a work space long or tall enough to pull engine and transmission as a unit to I have to do it another way. The tranny is about 15" tall plus whatever you set it on to move it from/to position. It takes some skill to keep a tranny balanced on a floor jack used as a tranny dolly but I haven't dropped a tranny yet.

You don't have to keep the drive shaft indexed to the tranny or diff but it makes sense to maintain relationships where they exist. Keep the front and rear drive shaft halves indexed, of course.

Sixto
MB-less

Thanks for the feedback, guys. I would definitely source a transmission jack, seeing I could get one for $30-$60 from a local pawn shop.