420SEL Won't Shift Into 3rd Now
Thread Starter
Newbie
Joined: Apr 2010
Posts: 3
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1986 420SEL
420SEL Won't Shift Into 3rd Now
It just started doing this...I was told by an ex mechanic that there are plastic check ***** in the valve body that need to be replaced, 1 for 1/3, and 1 for 2/4....as it starts out in 2nd I can go maybe 30mph but that's about all I want to spin the engine at. Fluid is fine and always was...
What do you think ?
Can I fix this myself ?
What do you think ?
Can I fix this myself ?
Newbie
Joined: Jul 2009
Posts: 12
Likes: 0
From: Salem, MA
300 SD
I had the same issue last month with my 300SD. It turned out that the elderly previous owner had an additive put in the transmission that eventually gummed up the valve body. After taking apart the valve body, freeing up the valves and flushing out the transmission and converter it shifts better now than when I got it. Good luck.
Thread Starter
Newbie
Joined: Apr 2010
Posts: 3
Likes: 0
1986 420SEL
Heard Cause Was Plastic ***** in Valve Body
I heard this from a retired mechanic. He said there are 2...1 for 1/3 and 1 for 2/4. They wear and then will not shift.
Either way, just gummed up, or the plastic *****, is it something I could fix at home without a lot of tools ?
I hate to junk the car just due to this.
Either way, just gummed up, or the plastic *****, is it something I could fix at home without a lot of tools ?
I hate to junk the car just due to this.
Newbie
Joined: Jul 2009
Posts: 12
Likes: 0
From: Salem, MA
300 SD
No matter what, the valve body has to come out of the transmission. Personally, I do a lot of my own repairs. But, automatic transmissions are something I have to leave to the experts. It's not an at home project.
All that said, having mine cleaned and flushed, including taking the valve body out and having it cleaned out ran about $650.00. Definately better than $2000 or more for a comlpete rebuild.
All that said, having mine cleaned and flushed, including taking the valve body out and having it cleaned out ran about $650.00. Definately better than $2000 or more for a comlpete rebuild.
Junior Member
Joined: Apr 2006
Posts: 59
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From: Phila. Pa
Sold-300ce AMG Twin Turbo
There is something you can look into.....there are two updated spring kits on the sides of the valve body (K1-K2)that are cheap to buy and fairly easy to change yourself if you are up to it if you have a set of ramps or access to a lift.Just drop the fluid/pan....there are two plates on the side of the valve body facing the front of car and two facing the rear.You want to remove the smaller of the two plates on each side (4 screws each)inside you will find a plunger with spring set on it.....change with updated versions.I know for sure the front one is easily accessible...can't remember if the rear one is blocked by something.If there is enough band material left,this should help it shift again...I would check the modulator on the side of the trans first though (for vac/pressure)....Good Luck!
