Transmission fluid leak at drain plug

plarkin

Member
I have had a very slight transmission fluid leak that my MB dealer wants $1,000+ to fix. Need to get part number from them on Monday. It was something about a J hook component leaking. I took a look underneath the van and only see fluid around the drain plug. Cleaned the bottom of the pan and around the side on the transmission; then went for a 10 mile drive and only see fluid on the drain plug. Tried to tighten the plug with a 5mm allen wrench but it would not budge. Tried to lossen it and felt like I was going to bend the allen wrench, need to get a hex socket. Is there a washer under the drain plug? Looks to me that there is some sealant when looking at the base of the plug.20201017_115455.jpg

The MB dealer changed the fluid about 12 months ago and it was after that I noticed the leak. Keeping an eye on the fluid level but still within specs a year and 24K miles later.
 
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Bobnoxious

GONE FISHING
Yes, there's a crush washer supposed to be there.

Well, let's hope the dealer pukes didn't strip and JB weld the plug. Is the sealant hard or soft?

Prior to wrenching, dig out the Allen hole, they collect road crud.
 

plarkin

Member
The Allen hole is clean, wrench seated well into the hole. Also the sealant is hard.
 
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mikeme

2015 LTV IB: 2015 3500 V6
There should be a washer under the plug. supposed to be replaced after use (but often reused)

more properly called a seal (or gasket) copper alloy chosen to allow a good seal at specified torque.

Hex socket is a good idea, as is a replacement plug and seal. If it will not come out, order a new pan, and use it while servicing the transmission (filter and fluid....)
 
Possibly over tightened by the mechanic and sealed with who knows what. Try applying heat with a heat gun before attempting to remove the plug. That might soften the sealant. Failing that, a new transmission pan.....
 

Dima74

Independent & Self Reliant - From Chattanooga TN
I have had a very slight transmission fluid leak that my MB dealer wants $1,000+ to fix. Need to get part number from them on Monday. It was something about a J hook component leaking. I took a look underneath the van and only see fluid around the drain plug. Cleaned the bottom of the pan and around the side on the transmission; then went for a 10 mile drive and only see fluid on the drain plug. Tried to tighten the plug with a 5mm allen wrench but it would not budge. Tried to lossen it and felt like I was going to bend the allen wrench, need to get a hex socket. Is there a washer under the drain plug? Looks to me that there is some sealant when looking at the base of the plug.View attachment 157544

The MB dealer changed the fluid about 12 months ago and it was after that I noticed the leak. Keeping an eye on the fluid level but still within specs a year and 24K miles later.
You did not specified what transmission you have on your van, but here are the part numbers for both 5 speed and 7 speed transmissions...
 

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Aqua Puttana

Poly - Thread Finder
A socket will help. An impact wrench or even battery drill driver with a socket can work on stubborn fasteners.

Another method to gain leverage is to insert the angle Allen wrench into the drainplug and then use a box end wrench slipped over the long end for leverage. If you use the leverage method be certain to hold the Allen key firmly into the drain plug so it doesn't slip out.

The picture in the first post here shows the "Torque Increaser" method used slipped over a 1/4" 12 point wrench.



vic
 

lindenengineering

Well-known member
This is not a problem for workshop where people get their hands oily
Remove the bloody pan and take it to to a bench .
Remove the plug by standard workshop techniques and refit it with a new plug and seal.
Labor charge is a standard I hour and we do lots of them when folk use imperial size allen sockets and metric is really required --Now let's talk about techniques of removing the torque converter drain plus that has been dicked up!!
Dennis
 

plarkin

Member
This is not a problem for workshop where people get their hands oily
Remove the bloody pan and take it to to a bench .
Remove the plug by standard workshop techniques and refit it with a new plug and seal.
Labor charge is a standard I hour and we do lots of them when folk use imperial size allen sockets and metric is really required --Now let's talk about techniques of removing the torque converter drain plus that has been dicked up!!
Dennis
Since I just had the fluid changed 1 year and 24K miles ago I can wait till after a trip this week to South Carolina from Tempe. The MB dealer also drained the torque converter on that tranny service so I hope there are no bloody surprises there!! Otherwise we will need to continue this conversation.
Thanks Dennis.
 
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Aqua Puttana

Poly - Thread Finder
... --Now let's talk about techniques of removing the torque converter drain plus that has been dicked up!!
Dennis
It is easier to keep yourself out of the sh*t than it is to get yourself out later.

Only use quality Allen tools when dealing with those plugs. I do buy and use Harbor Fright tools, but not for jobs like that.

:2cents: vic
 

lindenengineering

Well-known member
Since I just had the fluid changed 1 year and 24K miles ago I can wait till after a trip this week to South Carolina from Tempe. But the MB dealer also drained the tongue converter fluid on that tranny service so I hope there are no bloody surprises there!! Otherwise we will need to continue this conversation.
Thanks Dennis.
Actually in the expedience of job turn arounds we have several spare pans, which is the trick! All ready to go.
A quick swappsie & that plug removal can be done at a later date when shop activity goes slow.
Off peak stuff!
Same goes for engine sump pans with drain plugs torn out.
No time to dick with it !
Change it
Dennis
 

Bobnoxious

GONE FISHING
Small, cold chisel technique and other solutions explained here.

 

plarkin

Member
Small, cold chisel technique and other solutions explained here.

Thanks for the video Bob. Fortunately mine is not stripped, yet anyway!!. Will be purchasing a 5mm hex socket and have a lot more leverage that I had with the allen wrench. That with some heat will hopefully take care of it. If not down with the pan and over to the work bench. Will update you with the status the end of November when we are back in Tempe. Will definitely replace the plug and use the right washer. Do you know what it should to torqued to?
 

Bobnoxious

GONE FISHING
IMG_4870.JPG
 

Jbernielh

Member
when I did the 5 speed in my wife's RV, even with the proper allen socket it wouldn't budge.. I knew if I'd kept going it would have stripped the drain plug or snapped the socket.. one good wack with the cold chisel on the side of the plug and no problem it came right out using the allen socket..

I'd bought a new plug anticipating a problem before hand, but wound up just reusing the original with the small wack and a new copper crush gasket..

Bernie
 

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