Best way to remove gearbox (with or without engine?)

[744Brillantsilber]

Hey everybody,
I plan to remove my gearbox during my rebuilt and initially planned to remove the gearbox (leaking seal on the primary pump) from the underside of a car (using a 4-collumn lift).
But now I read that some of you prefer putting the car on stands and remove engine and gearbox through the open hood! Since working on the engine is way easier with the engine removed, this sounds very interesting!!
Can you please give me your personal opinion/experience about both methods?
When removing the engine and gearbox together, can you give me a roughly estimated height I need in my garage and what lifting height the engine-crane needs?
I would highly appreciate your opinions!
744

 

[gerryvz]

If you are just going to work on the transmission and re-seal it, then I would just remove the transmission itself. If there are any engine jobs that need to be done (also re-sealing, hose replacement from the power steering and heater, etc.) then I recommend removing the engine and transmission as a unit. It really depends on the scope of the job -- it's do-able either way.

In terms of room needed -- no more height than would be required to have the hood all of the way up in the vertical position ... so definitely about 3 meters of vertical space - MINIMUM. 4 meters would be even better. You want the hood to be raised vertically, even if you are lifting the car up off the ground, and not to hit anything overhead.

 

[gsxr]

Ditto what Gerry said. Pull the transmission out the bottom. It's not that hard.

If you want to pull the engine also... FIRST pull the transmission out the bottom, then remove the engine straight up. Much, much easier... IMO anyway.

Removing the pair together is a nightmare, requires an engine hoist capable of very high lift, and a leveler that can adjust to a steep angle. And it may require 2 or more people to avoid smashing things in the engine compartment using this method. Yes, I know the factory installed them together, but they also had the proper equipment and training to do it.

Photos below show the engine going straight in by itself, no angle...

 

[Sean L.]

How long would it take a reasonably competent mechanic at a professional shop with with a lift and tools to remove and replace a transmission? My guy gave me a quick "Alldata" estimate of 14 hours. That seems very high. I have 154,000 miles and a selector shaft seal leak. I will make another post on that under the Transmission Leak thread. He said that he could replace the seal with the transmission in the car, but It might come down to me just biting the bullet and putting in a Sun Valley rebuild. Thanks.

 

[gsxr]

From memory, I want to say it took me ~4 hours to have the transmission on the floor, last time I did this. Takes longer to re-install, maybe 6 hours, for a total of ~10 hours? This assumes no frozen or rusted fasteners, and no unexpected problems. Interestingly, I just looked up the official MB book time (ASRA) and it is... 9.9 hours for both .034 and .036 chassis, for transmission R&R only (no other work done).

Selector shaft seal can be replaced WITHOUT removing the transmission... done this on at least 2 different 034/036 chassis. Takes a few hours, worst part is cleaning everything and trying to press the new seal in with very limited space for tools. No need for a rebuilt transmission if only one seal is leaking! I can't recall the total time but I can't imagine it would be more than 4-5 hours to change the selector shaft seal with the trans in the car.

 

[744Brillantsilber]

Hey Gerry, hey Dave,
thank you very much for your opinion!!! I will do some measurements and think about it the next days. I am not in a hurry...

 

[Sean L.]

Selector shaft seal can be replaced WITHOUT removing the transmission... done this on at least 2 different 034/036 chassis. Takes a few hours, worst part is cleaning everything and trying to press the new seal in with very limited space for tools. No need for a rebuilt transmission if only one seal is leaking! I can't recall the total time but I can't imagine it would be more than 4-5 hours to change the selector shaft seal with the trans in the car.

This is so helpful, thank you. Are there other "While I am in there" seals or other work to be done if it is just the selector shaft seal that is leaking?

 

[gsxr]

This is so helpful, thank you. Are there other "While I am in there" seals or other work to be done if it is just the selector shaft seal that is leaking?

If you are not removing the transmission from the car... closely inspect everywhere else to see if any other seals are leaking. Consider replacing those if necessary. The selector shaft seal is one of the bigger hassles, the other two are the B1 cover, and the control pressure / Bowden cable. All three of these are not fun with the trans in the car. Most others are just tedious. I normally don't mess with seals unless they are leaking... but if the transmission comes out, replace EVERY external seal.

 

[gerryvz]

In addition, if the transmission comes out of the car for repair or re-seal, DEFINITELY order the "blanket" that fits in the transmission tunnel above the transmission. This tends to get eaten away and disintegrated over the years, as a soft part, and there will NEVER be a better time to replace it when the transmission is out of the car.

It's an important thing to do.

 

[gsxr]

DEFINITELY order the "blanket" that fits in the transmission tunnel above the transmission.
It's an important thing to do.

....and, sadly, NLA.

 

[gerryvz]

I wonder if another model's blanket could be adapted to fit.

 

[IslandMon]

....and, sadly, NLA.

I have one on the shelf if anyone needs it badly. Shipping going to be higher than you’d think because it needs a very large box.