[W126 Coupe] Oil leak - transmission advice

[Iain Gunn]

There are 2 distinct things on automatic transmissions that people get mixed 
up about.
    Slipping: is caused by not enough fluid pressure to hold the clutch 
packs together, or clutches are worn out. Once slipping starts It usually 
stays, Slipping will happen in all gears as the clutches effect all gears. 
Usually worse in the higher gears. One way to check clutches is to do a 
brake stand. Foot on the brake and run the engine up, transmission in gear. 
You should feel the car trying to pull hard without moving and the RPM will 
reach a maximum and not go higher. If the rpm keep increasing without heavy 
torque from your vehicle, the clutches are not working properly. Most times 
this is a fatal condition and the transmission needs repaired.
    Flare: Is caused by, the linkages from the throttle out of position, a 
faulty modulator valve, a valve body, with some blockage, a leaking pump or 
servo.
The effect of this is, when you hard accelerate, as the transmission shifts 
from one gear to the other, the engine reves up but the car doesn't shift 
into the next gear properly, kind of like it went to neutral temporarily. 
When you back off the accelerator, it eventually pops in, usually with a 
jerk., Sound familiar?
When, you back off on the accelerator, in a low gear with high RPMs, the 
pump pressure rises dramatically, and the transmission shifts. Once it is 
engaged it is usually OK. This is not a fatal condition and can sometimes be 
corrected, often improved with a transmission filter and fluid change. See 
Jonathans post on fluid.
Now the more you allow the transmission to flare, the more you are slipping 
the clutch pack and you will burn out the clutches, so don't do this, 
because if you drive the vehicle normally it usually shifts just fine.
    In conclusion: I've had 3 MB's and they all seem to have a flare issue 
between 3rd and 4rth?? when driven hard. I have resolved the issue in 2 the 
560's by changing the fluid and adding Lucas transmission conditioner, which 
tells me its old seals that have shrunk with age and previous owners not 
changing the fluids. Change you ATF more often, at least every 10,000 miles, 
its cheap insurance.
    On the 190E 2.6,  haven't resolved, and this is definitely a MB design 
issue, cause the forums all tell of the same issue. I haven't changed the 
modulator valve yet, could be some of the issue, but I don't think so, but 
haven't found a transmission mechanic that has resolved this issue with this 
transmission. Probably needs a valve body upgrade or a modified shift kit. 
Haven't been able to find this either. So I adjusted the Bodine cable, to 
short shift the transmission and when I need to pass or downshift, I do it 
manually.
 If you know a transmission mechanic that I can email or talk to about the 
190 issue, I'd appreciate any help in this area.
Hope this helps, Iain Gunn, Mount Forest, Ontario, Canada
----- Original Message ----- 
From: "Andrew Sporner" <asporner at googlemail.com>
To: "Mercedes Coupes Mailing Lists" <mbcoupes at mbcoupes.com>
Sent: Sunday, June 22, 2008 8:12 AM
Subject: Re: [W126 Coupe] Oil leak - transmission advice



>I ran mine this way for 2 1/2 years of heavy auto-bahn driving

> (sustained speeds of 120)

> with no ill effect.

>

> Note about refilling.  The level should only be checked when the

> transmission is hot!!!

> (overfilling is deadly!)  Another point is that this should be done

> after shifting between

> the gears.    I was told that this should be repeated after a few weeks.

>

> Andy

>

>

> On Sun, Jun 22, 2008 at 1:34 PM,  <stefansj at canisius.edu> wrote:

>> I only have slipping from 2nd to 3rd as well and only when cold. I'll try 

>> the flush

>> first and maybe some Lucas? Jonathan, I trust your diagnosis but it 

>> doesn't

>> bother me to the point of a rebuild YET lol. As for the oil, I'll change 

>> it out as

>> soon as possible. After calling the dealership they told me 0w-40, didn't 

>> think

>> they could lead me in the wrong direction! Thanks again everyone, Jas

>>

>> ---- Original message ----

>>>Date: Sun, 22 Jun 2008 09:36:04 +0200

>>>From: "Andrew Sporner" <asporner at googlemail.com>

>>>Subject: Re: [W126 Coupe] Oil leak - transmission advice

>>>To: "RONNY GEENEN" <ronny.geenen at verizon.net>, "Mercedes Coupes Mailing

>> Lists" <mbcoupes at mbcoupes.com>

>>>

>>>Hi,

>>>

>>>I have an 82 500 SEC (189,000 Miles) and have had a slipping when the car

>> was

>>>cold (contrary to what I had heard) during acceleration between 2nd

>>>and 3rd gear.

>>>The car would go into a higher RPMs without additional speed.  Last

>>>year because

>>>of an oil leak I burned out the transmission (would not shift any

>>>longer at all) and had the

>>>transmission rebuilt (admittedly I am skeptical about the work as this

>>>guy got the

>>>car into a fender bender and assured me that it was only a 300 EUR

>>>affair.  He said

>>>he would handle it.  Thankfully the insurance sent me a copy of the

>>>estimate which

>>>was over 2600 EUR!!  He had planned to fix the headlight and pocket the 

>>>rest!

>> A

>>>quick letter from my lawyer did the trick)

>>>

>>>At first after the rebuild this behavior didn't exist but it is back

>>>again.  However I also

>>>notice that my '96 C-180 does this too.  Either its a "feature" or a

>>>common problem.

>>>the C-180 is also an automatic.

>>>

>>>Is this a "feature" or a "failure"?

>>>

>>>

>>>Andy

>>>

>>>On Sun, Jun 22, 2008 at 7:59 AM, RONNY GEENEN

>> <ronny.geenen at verizon.net> wrote:

>>>>

>>>>

>>>> Jonathan says:

>>>>

>>>> The ONLY M1 you should be running is the 15/50 Extended

>>>> Performance..this still has the zinc/phosphate that our engines Need.

>>>>

>>>> As for the trans, if it's slipping and adjusting the mod/changing fluid

>>>> doesn't fix the problem it's time for a rebuild.  I'd suggest using B&M

>>>> trick shift....it's by Far my pref'd fluid for our transmissions.

>>>>

>>>>

>>>> From what brand is the 15/50 Extended Performance and B&M trick shift?

>>>>

>>>> Ronny

>>>> Glendora, Ca 91740

>>>> 1987 560 SEC

>>>> 1984 300 SD

>>>>

>>>>

>>>>

>>>> The MB Coupes Website!

>>>> W126 SEC Mailing List

>>>> Postings remain property of MB Coupes, L.L.C.

>>>>

>>>The MB Coupes Website!

>>>W126 SEC Mailing List

>>>Postings remain property of MB Coupes, L.L.C.

>>

>> The MB Coupes Website!

>> W126 SEC Mailing List

>> Postings remain property of MB Coupes, L.L.C.

>>

> The MB Coupes Website!

> W126 SEC Mailing List

> Postings remain property of MB Coupes, L.L.C.

>