722.315 out of an '85 300TD. This transmission was making an audible growling noise (think bad unitized wheel bearing in a newer car - not a grinding or harsh noise, just a growl/howl) that corresponded to engine speed, but was drowned out at highway speeds. Was more noticeable inside than under the hood. It needed to come out to replace the pump seal, anyway, so I'm trying to determine whether there's any indicators in the pump or if it could be a plugged filter or bad torque converter.

All manuals I can find say "If front bushing has wear or damage, replace pump." All I see is evidence of light rubbing by the torque converter snout - no apparent damage or severe wear. Opinions?

Attached Thumbnails

         

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'82 300CD
"Pearl", the very first turbo diesel 123 coupe
Totaled 11/23/18, rebuild in progress.
'85 300TD, "Artemis".
'78 300D euro, "Ol' Red", mostly retired.
'85 300D, "Gandalf".

Did you find the source of the noise? If your transmission was operating fine except for the noise. I'd fix the problem with the noise, any seals you have access to, and replace the filter and transmission fluid. That's what I'd do.
Roddy

Sent from my SM-G900I using Tapatalk

As explained above: I had to remove the trans. to fix the leak, either way, and if I could find the cause of the noise while I had it apart, all the better.

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'82 300CD
"Pearl", the very first turbo diesel 123 coupe
Totaled 11/23/18, rebuild in progress.
'85 300TD, "Artemis".
'78 300D euro, "Ol' Red", mostly retired.
'85 300D, "Gandalf".

It looks OK to me - the best check after reassembly is to see if it still pumps within the prescribed specifications (see chap 27 if you can get it - ATSG or WIS info if you can get it - there's also a fair amount of copied info on BW too)

These pumps are pretty simple - pretty stupid - they only have to be good enough to produce the prescribed min main pressure

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

If the noise is a whine like a bad power steering pump then the source of the noise is the torque converter.
Look it up on line. Torque converter noise.
Roddy

Sent from my SM-G900I using Tapatalk

This is an old thread. However, I have pulled my front trans pump off to inspect the bearing shown in the pictures. The reason why is I had a non-Mercedes transmission that I replaced the front seal on leak again a few months later. Upon pulling the pump off of that I found that bearing was loose and worn. I suspect that too much pump pressure was reaching the new seal and causing the leak.

Back to the Mercedes trans pump bushing. I was looking for that bushing and there is not a lot of sources of it. Cobra Transmissions was a source at about $13 plush shipping. The other sources were over $20 plush shipping.

https://cobratransmission.com/index.php?main_page=index&cPath=1_988_990_1001_1005 Bushing

Have not looked at my bushing yet.

Another reason for pulling the pump is that I have since 2007 had a leak up front and the rear also. Kent be at that famous site has that if your transmission leaks sitting the leak could be the pump gasket and or the Pump O-ring as well ask the front pump/torque converter seal. In order to get at the pump O-ring the pump has to come out and one of the transmission pistons needs to be removed.

You should do your research on this because there is the bushing at the toque converter and of the pump and there is a bushing to the rear.

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84 300D, 82 Volvo 244Gl Diesel

To get the pump apart you need to remove the reverse piston (which I am not going to detail) and then remove the bolts that are under it.

When it is apart the O-ring that is there was hard enough it cracked removing it. So checking that was not a waste of time.

The bearing is not perfect but reusable.

I am also changing the reverse piston inner and outer seals (which may be called a boot in the EPC). They looked OK but were kind of in-elastic.

There is also 2 split plastic seal ring on the rear shaft that are about $4 each depending on the source. I may replace those also but had not decide.
When I assembled the Van transmission I managed to ruin the split plastic seals and had to order more. So it may be best to at least have them on hand.

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84 300D, 82 Volvo 244Gl Diesel