Trans slips after service
Thread Starter
Newbie
Joined: Oct 2018
Posts: 6
Likes: 1
1983 Mercedes 300d
Trans slips after service
Hi,
I have a 1983 300d. The trans was shifting hard so I decided to change the trans fluid and the filter. The car only has 66,000 miles on it, and I believe it is the first time the transmission has ever been serviced. I drained the pan but did not drain the torque converter. I changed the filter and buttoned everything up, there are no leaks.
I drained about 3 1/2 quarts of old trans fluid out of the car and ended up replacing about 4 quarts to get it just below the top line on the dipstick. I replaced it with Valvoline Dexron III / MERCON
So, the transmission no longer shifts hard. It now shifts very smoothly. It does, however, slip slightly between 2nd and 3rd gear. It won't slip if I take it very easy.
Why would this happen? I did not knock any thing off, vacuum lines, etc...My research tells me that the fluid type is what is recommended. I did not put synthetic fluid in the car because I don't think it was ever changed. I did not change torque converter fluid because I read it is better to leave that alone.
It is a very low mileage trans. It shifts much better now, no clunking. Just the slip between 2nd and 3rd.
Any thoughts why it now slips?
Thanks in advance.
I have a 1983 300d. The trans was shifting hard so I decided to change the trans fluid and the filter. The car only has 66,000 miles on it, and I believe it is the first time the transmission has ever been serviced. I drained the pan but did not drain the torque converter. I changed the filter and buttoned everything up, there are no leaks.
I drained about 3 1/2 quarts of old trans fluid out of the car and ended up replacing about 4 quarts to get it just below the top line on the dipstick. I replaced it with Valvoline Dexron III / MERCON
So, the transmission no longer shifts hard. It now shifts very smoothly. It does, however, slip slightly between 2nd and 3rd gear. It won't slip if I take it very easy.
Why would this happen? I did not knock any thing off, vacuum lines, etc...My research tells me that the fluid type is what is recommended. I did not put synthetic fluid in the car because I don't think it was ever changed. I did not change torque converter fluid because I read it is better to leave that alone.
It is a very low mileage trans. It shifts much better now, no clunking. Just the slip between 2nd and 3rd.
Any thoughts why it now slips?
Thanks in advance.
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Joined: Jan 2009
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From: V E G A S
1922 Ford Model T / no OBD
You changed heavy ATF with lighter ATF.
That makes for smoother shifting, but also more slippage on gear changing.
That is adjustable by valve on bottom of the transmission. I did it long years ago, so don't remember details, but fellow W123 owners should give you update.
Disconnecting vacuum line from transmission would make for abrupt shifting.
That makes for smoother shifting, but also more slippage on gear changing.
That is adjustable by valve on bottom of the transmission. I did it long years ago, so don't remember details, but fellow W123 owners should give you update.
Disconnecting vacuum line from transmission would make for abrupt shifting.
Thread Starter
Newbie
Joined: Oct 2018
Posts: 6
Likes: 1
1983 Mercedes 300d
I just returned from a 75 mile drive and it is no longer slipping. A little noisy clunk from 2nd to 3rd gear but much better and no slipping at all. I did not drain the torque converter so I am thinking that the news fluid mixed with the old and it's fixed the issue?
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