Transmission Removal

[mbboy]

Does anybody happen to know where on the 107 CD I can find the procedure for removing and installing the transmission on an 81 380sl?

Reverse gear is starting to slip, as it's apparently prone to do on the 722.3 tranny. So I'm considering either replacing my tranny with a lower mileage used one, or having the reverse clutch rebuilt.

If anyone here has removed the tranny of a 107, I'd also appreciate learning more about it.

Thanks in advance.

[Genbiltstein]

Disconnect the batteries and make sure you support all four tires off of the ground. Get the car high enough for the transmission to clear from underneath. Including the transmission jack you will be renting. You will wish you had if you don't.
Drain the transmission and disconnect the transmission oil cooler lines.
Get a hydraulic jack and support the engine. Disconnect the body plates off from under the transmission.
Disconnect the grounding strap.
Disconnect all wiring from the transmission.

Disconnect the transmission filler tube and remove.
Disconnect the driveshaft. 19mm (two wrenches)
While rotating the engine remove the six bolts from the flexplate. Leave the hex bolts in place, there are three or so.

Lower the engine a bit and remove the starter from the bell housing.
When you are ready to remove the transmission make sure you keep the same angle engine to transmission. If you don't you run the risk of damaging the Transmission pump and spline. Remove the torque converter with the transmission if possible.
It will be a lot of work so take your time.

[mbboy]

Originally Posted by Genbiltstein

Disconnect the batteries and make sure you support all four tires off of the ground. Get the car high enough for the transmission to clear from underneath. Including the transmission jack you will be renting. You will wish you had if you don't.
Drain the transmission and disconnect the transmission oil cooler lines.
Get a hydraulic jack and support the engine. Disconnect the body plates off from under the transmission.
Disconnect the grounding strap.
Disconnect all wiring from the transmission.

Disconnect the transmission filler tube and remove.
Disconnect the driveshaft. 19mm (two wrenches)
While rotating the engine remove the six bolts from the flexplate. Leave the hex bolts in place, there are three or so.

Lower the engine a bit and remove the starter from the bell housing.
When you are ready to remove the transmission make sure you keep the same angle engine to transmission. If you don't you run the risk of damaging the Transmission pump and spline. Remove the torque converter with the transmission if possible.
It will be a lot of work so take your time.

Thanks very much for the info. The only things that makes me a little hesitant to try this are:

1) The need to lower engine, which evidently means loosening the engine shocks and mounts. Is this really necessary or can the tranny be removed without this?

2) Having to remove the starter, since I did this once, and getting the top 10mm Allen bolt out was a PITA. Is that why it's necessary to lower the engine?

3) Seems to me that the transverse exhaust pipe also has to be removed to lower the tranny, which means removing the exhaust from the manifold? Yes?

Thanks in advance for the clarification.

[rs899]

I haven't done this yet on a R107( although I have one, not in my sig), but I think I can answer some of it.

The starter bolts go through the bellhousing and the engine adapter, so they must be removed. You may be able to leave the starter hanging there by its wiring, or with other support.

You will need to remove the exhaust/cat.

There may be enough flex in your mounts and shocks ( probably have to disconnect shocks)to just push up on the front of the oil pan. Point is you need to angle the transmission downward. Make sure you remove throttle linkage etc and check for fan to radiator clearance.

I was hoping your early 380SL had a 722.1 ( with reverse band adjustment) but I guess you are not so "lucky".

Is it really possible to get to those damn top 2 bolts on an R107? Somebody needs to confirm that....

[cth350]

There are a couple of tools that will make your life easier...
- A very long extension rod
- A 10mm allen key with a built in swivel joint
- A 17mm 6 point socket with a built it swivel joint

All should be available from sears.

Removing the starter bolt is easy if you start from the back of the transmission and look forward towards the bolts. You'll see how the long extension can reach the bolts from there.

In the absence of a transmission jack, get two nylon straps and scrap piece of plywood the size of your transmission oil pan. Use the straps to secure the wood to the transmission (really fun). The use a conventional jack to carry it up and down.

If you are capable of bench pressing 140 pounds, while under a car, getting dirt in your face as well as laying on cold concrete, you can do with out the transmission jack. But you'd much rather have the jack.

-CTH
PS. Don't forget a 17mm flare wrench to undo the two metal pipes that connect the transmission to the cooler.

[mbboy]

After considering the amount of work this would require, I opted to have a local transmission shop remove the tranny, and replace the B3 clutch pack, along with anything else that needs replacing, in the hope that I'll be able to get another 150-200k miles out of it.

Although you never know what problems may arise, the fact that the shop is local and has been in business for 20+ years without any BBB complaints gives me a sense of security that they'll stand behind their work for a reasonable period of time.

However, thanks very much for the helpful responses.

[rs899]

You're welcome. Let us know how it all worked out. I didn't find transmission work itself all that difficult, just different. When you put the whole endeavor together (pull it, fix it, install it) it's a pretty big deal and takes a lot of time...