Transmission 722.418 Governor Test Question
 

I have a '90 300D with a transmission problem that I'm hoping somebody can shed some light on. I've followed past threads and did not find similar problems.

Symptoms are that reverse works and 1st and 2nd gear forward work. That's it.

I don't know the history of the tranny but it has good fluid (although I did find a small piece of broken grey plastic in the pan). I opened and found piston B2 to be just fine. I believe I have a problem with the governor.

1) How I can test governor?

2) Is it possible to remove the governor without removing the tranny from the car?

Thanks in advance for your help,

I had a problem with my 91 300d where it wouldn't shift out of first gear. It was a broken gear on the governor. If you remove the rear trans mount, push the trans as far as possible to the passenger side (i used a motorcycle tie down strap to hold it over), remove the big ring that holds the governor cover on and remove the cover (this is on the left rear of the trans case) you can see the governor. To remove it you must squeeze together or seperate the ears (I can't remember which) on a snap ring behind the governor weights then pull it out. Then make sure the gear is good with no broken teeth. In the shaft there is a valve that must move freely. Wash it very good with clean brake cleaner or something like that. It must be clean. The hard part of the job is replaceing the governor. If the gear is broken or damaged in any way, just go ahead and order it from MB. I looked for 2 days trying to find one at transmissions shops, parts houses, etc. I finally ordered one from MB, had it the next day, and it came out to the grand total of $1.90 plus tax.
By the way, my gear was broken in half. 1 half was on the shaft and the other half has yet to be found. I guess it is in some hiding spot. It's been over a year so I guess it likes it where ever it is.

Governor Help!
 

I took the governor cover off and I can turn it by hand about 50 degrees which I read indicates that the gear is broken, but I am unable to remove it. I see that there is a cover on the other end of the governor, but I dont know whether i need to take off the cover for me to be able to remove the governor.

On the 722.4 the governor is held in place with a snap ring, you will need a long snap ring
Pliers to reach the ring. Look in front of the governor weights, that is were you will find the ring.
Once removed you can replace the plastic driven gear on it, but the cause is a broken rear pump
Check valve in the auxiliary valve body.

Thanks C32AMG for the information. Can you direct me where the rear pump (is this the secondary pump?) is located. Also where is the check valve in the auxiliary valve body?

Thanks

Is that manual I sent you working out?

The diagram shows how to remove the governer...hope it helps out :)

Thank you for the manual Brandon, it is very helpful. But my governor is mounted differently.

Thanks

You might do a google search. I came up with a BUNCH of good information about the merc. trannies.

Just a thought :)

The rear pump is on the passenger side, it has three 5mm bolts. To remove the governor, compress and
Hold the snap ring, and then pull the governor from its bore. The governor has a square notch, align it with
the notch in its bore upon installation. Replace the rear pump check and clean the governor screens next
to the valve. Check valve part # 126 270 0589, Plastic governor driven gear part #201 274 03 15.
Clean any debris from the steel drive gear.

Thank you very much for the great pictures! They cleared up alot of my questions. But I still have not found pliers that are long enough for me to be able to remove the clip that holds the governor in place.

Thanks

More problems with transmission
 

I removed the secendary pump and it was stuck, some plastic got between the pump gear teeth and put it out of commission. I am still unable to remove the governor clip, and I am now looking for a pair of 2.5 inch long nose 90 degree pliers. After inspecting the helical gear (plastic) which drives the governor, some of the threads are missing. Is the helical gear replacable without removing the transmission? I was thinking that I could just disconnect the drive shaft, open the rear cover and replace the broken gear.

Size of twelve-point collar nut
 

Could sombody help to indentify the size of the twelve-point collar nut which tightens the flange (drives propeller shaft) on a 722.418 transmission?

I found the answer by bying the collar nut today and is 30MM.

Thanks

To change the driven gear, the governor has to be removed from the transmission, you can’t
Remove the retaining ring thru the tail. If you can not find the right snap ring pliers, try a
Long nose needle pliers.
I am off to work, preparing for the blizzard, they are predicting 16 inches of snow, and I will be
Back around 1pm EST. I will try to help you then.




http://www.mastertechtrans.com/post/gear1.jpg

Thank you very much for the pictures yet again, and im glad that you just saved me $2000. Because I would have never guessed that the governor could have been the problem.

I have all the parts, but I have to open the tail of the transmission to change the main hecial gear that drives the governor. I have one problem though, in the pictures that you showed me previously, it showed the check valve was installed in the removable cover. My transmission though is different, when I removed the rear pump all I found was the check valve spring so I dont know where the check valve needs to go.

The auxiliary valve body is bolted to the valve body spacer plate, the valve body and spacer plate must be
Removed to access the auxiliary valve mounting bolts. You will need a 33MM or 1 3/16 12 point thin
Wall deep socket, for the nut that retains the drive shaft mounting yolk / flange. Removing the transmission
Cross member will allow more room.