[W126 Coupe] Oil leak - transmission advice

[Jonathan]

We have a kit that you can use to modify the 3-4 shift so you can firm 
up Just that shift...it's a pretty common problem...  Only thing you 
need to drop the valve body to put it in...  it's not hard, just messy 
and you need to pay attention whilst doing so.

I used to use the lucas more often until I found the B&M fluid...  Lucas 
still has additives to help smooth clutch engagement, ie slippage..  
B&M's additives are designed Strictly w/ Grip in mind.  On my track car 
2-3 was so-so, 3-4 was getting bad with about 200K on the box.  Added 
6lbs pressure (two turns) w/ the mod valve, did a flush w/ B&M trick 
shift (their standard not synthetic fluid the first time around) and it 
was as though 100K worth of wear was done away with.

Jonathan

Iain Gunn wrote:

> 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

>


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