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Transmission not going into drive or reverse on 450SE

Started by silverlakemarket, 18 June 2018, 10:43 PM

silverlakemarket

Hi All,

Newbie here. I looked all through the forums and youtube to see if anyone else had the same issue but have not been able to find it.

Basically the transmission is not engaging, I checked the fluid and there seems to be enough oil in there. When I turn the car on the idle is abnormally high and if I keep the car on long enough it begins to blow thick white smoke that smells burnt.

Has anyone else ever had this happen to them or know why I might have this problem?

Squiggle Dog

Hmmm... I wonder if the shift modulator diaphragm has ruptured, and so the engine is sucking in and burning transmission fluid through the hole in the diaphragm.
Stop paying for animal cruelty and slaughter. Go vegan! [url="https://challenge22.com/"]https://challenge22.com/[/url]

1967 W110 Universal Wagon, Euro, Turbo Diesel, Tail Fins, 4 Speed Manual Column Shift, A/C
1980 W116 300SD Turbo Diesel, DB479 Walnut Brown, Sunroof, Heated Seats, 350,000+

silverlakemarket

Hi Sqiggle dog thanks for the quick reply.

If that was the case, does that mean my transmission is done?

TJ 450

Not necessarily, you would need to continue troubleshooting.

I would pull the plastic cap off the modulator vacuum element and check for fluid loss.

Following that it could be low system pressure or blocked lines.

Are you checking the level at trans operating temp?

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

Squiggle Dog

If the only problem is the vacuum modulator, it is an external part that can be replaced. It may only be part of the problem. A bad modulator will cause white smoke and shifting problems, but I don't think it has anything to do with being able to move the car forward or backward. However, if the transmission fluid is low from it being sucked into the engine, that could cause the transmission to not engage.
Stop paying for animal cruelty and slaughter. Go vegan! [url="https://challenge22.com/"]https://challenge22.com/[/url]

1967 W110 Universal Wagon, Euro, Turbo Diesel, Tail Fins, 4 Speed Manual Column Shift, A/C
1980 W116 300SD Turbo Diesel, DB479 Walnut Brown, Sunroof, Heated Seats, 350,000+

daantjie

I echo all what has been said so far as for tips.
I can also add to always start and think simple, especially with transmission woes.  As a first course of action, always drop the pan and "read" the situation.  Burnt fluid is always bad news and a sign of a terminal transmission.  If you see lots of sludge and metal flake and bits, ditto, bye-bye trans.  You can nurse it for a few more K miles, even more if you are lucky by dumping in fresh fluid and a bottle of Trans X, but this will just be a band aid.  Of course also change the filter.
If fluid is good and no/little sludge and debris then yes you need to start looking at modulator and control pressure adjustments.
Daniel
1977 450 SEL 6.9 - Astralsilber

daantjie

Maybe just further as well.  As far as I know no gear engagement, reverse or otherwise, points to working pressure too low in the trans, thus the bands are not being applied.  Low pressure may be caused by too low fluid in the trans, so again make triple sure you have enough fluid.  If indeed the modulator diaphragm has been gone for a while then it is likely that you have been burning off trans fluid via the intake for some time and thus you could just be running low on fluid.  This would be the best case scenario 8)
Daniel
1977 450 SEL 6.9 - Astralsilber

raueda1

Quote from: daantjie on 19 June 2018, 12:52 PM
Maybe just further as well.  As far as I know no gear engagement, reverse or otherwise, points to working pressure too low in the trans, thus the bands are not being applied.  Low pressure may be caused by too low fluid in the trans, so again make triple sure you have enough fluid.  If indeed the modulator diaphragm has been gone for a while then it is likely that you have been burning off trans fluid via the intake for some time and thus you could just be running low on fluid.  This would be the best case scenario 8)
To amplify on that, reverse should work even if bands and pretty much everything else is shot provided there's enough fluid and the torque converter is working.  Please don't ask me how I know this.   ::)  No reverse means no torque converter and that means low pressure, low fluid or blown torque converter.  BTW, there's a pump in the torque converter, that could be shot too. 
-Dave
Now:  1976 6.9 Euro, 2015 GL550
Before that:  1966 230S, 1964 220SE coupe, 1977 Carrera 3.0

silverlakemarket

Hi All,

I appreciate all the helpful information.

Going to take the car to a shop here in LA, if the cost to repair is too expensive the car will be for sale.

Anyone know any reputable shops in Southern CA, mainly LA area?

daantjie

If your car is otherwise in nice shape, you might consider doing a transmission exchange via Sun Valley in CA.  They have a very good reputation and seeing as you are in LA and they seem to be pretty much down the street from you in San Fernando, you should be able to get an exchange unit pretty quickly.  Then you'll be only out the cost of the swap and shop labour of course. I think exchange units are between 1500 and 2000 USD.  They take your old trans and you buy the new one for them on exchange basis.
As for shops, I have heard good things about Marx Mercedes in Costa Mesa, though of course I cannot personally vouch for them.  Another one in Tarzana - Mr MB, gets good reviews but not sure if they work on the oldies.
Daniel
1977 450 SEL 6.9 - Astralsilber

Harv

Quote from: silverlakemarket on 20 June 2018, 12:31 PM
Going to take the car to a shop here in LA, if the cost to repair is too expensive the car will be for sale.
Anyone know any reputable shops in Southern CA, mainly LA area?

Sun Valley is the go-to guys for Mercedes transmissions.

https://www.mercedesdismantlers.com/index.html
1980 300SD
1983 240D
2000 E55 AMG
2002 G500

silverlakemarket

Hi Guys.

I found a transmission its a, 4-speed automatic 722.313

I read that the 450SE comes with a 3 speed transmission.

Would there be any issues putting this transmission on my car?


daantjie

Quote from: silverlakemarket on 25 June 2018, 10:50 AM
Hi Guys.

I found a transmission its a, 4-speed automatic 722.313

I read that the 450SE comes with a 3 speed transmission.

Would there be any issues putting this transmission on my car?

What do you currently have, 3 or 4 speed?  Most important is if will bolt on to your current setup without modification.  Looks like the 722.313 was fitted to the 107 models in the 80's from what I can tell.  Best to talk to Sun Valley, they really are the go to guys on this.
One thing to note is that the 3 speed always starts in 1st, whereas the 4 speed starts in 2nd, unless you floor it off the line, then it will kick down into 1st, or you can move the shifter to "L", or "1", and then back to "D" to make it start in 1st.
Daniel
1977 450 SEL 6.9 - Astralsilber

TJ 450

Correct, any 722.3xx trans won't work as they have a different bolt pattern etc. You would need to source one preferably from a 450SE/L although it's likely a 450SL unit is the same.

I would first confirm the trans has definitely failed though.

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500