No kick down after 35 Miles speeds

[murat]

Hi,
My auto transmission  kick down does not function  if the car speed exceeds 35 miles. Under 35  Miles,  it kicks down without any problem. Any help appreciated.
Best Regards
Murat

[ja17]

Hello murat,  
Check the engine timing, as it effects  engine vacuum. Engine vacuum, in turn, effects transmission function. Make sure that the vacuum connection from the intake manifold to the transmission is good. Also remove the access cover inside the car and check to make sure that the transmission linkages work. You may want to spray some lube on the linkage pivots.

The transmission linkage can be adjusted by using the turnbuckle. This will change kick down. I do not recomend you do this unless you check everything else first. Accurate adjustment of the linkages and the modulator pressure on the transmission should be done with a pressure gauge using the specs in the BBB.  

What is the history of this problem? The solution may just be a simple engine timing adjustment. Start by setting the timing to 30-35 degrees BTDC at 3,000 rpm.

[murat]

Hi
My transmission shifts with no problem up and down but I cannot make kick down when my speed exceeds 40 miles/h.
Any help appreciated.
Regards
Murat

[murat]

Thank you for your advice John,
My transmission is new reconditioned and timing is also new adjusted. The history of the case is as you can understand very new. I adjust the transmission with the gauge according to BBB. At idle with no vacuum connected my pressure is 0,9 kgf/cm2. At high speed 2,9 Kgf/cm2 and kick down switch pressed 4,5 kgf/cm2. After this adjustment it shifts up and down very smooth. If I kick down under 35 miles/h no problem, it shifts down. But over 35-40 miles it does not reacts when I press the kick down. I will check again the timing. My car is a late 250SL and has a Bosch  vacuum retard distributer 051 with pertronix ignitor. Could you please describe how to adjust the timing? On idle with  vacuum connected or not? 
Regards
Murat

[GGR]

Merhaba Murat!

Nerede oturiyorsun Istambulda? Ben Izmirde dogdum. Fransizim ama babam orda calisiyordu. Dokuz yasindayken Italyaya oturmaya gittik. Turkceyi biraz atirliyorum.

The trans may be shifting down by itself under 35 mph. Try the same test but without pressing on the kick-down. Also try to see if the kick down button works properly by controlling it with a multi-meter. 

[murat]

İstanbul' da Suadiye - kadıköy'de oturuyorum. fakat küçük yaşınızda ayrıldığınız halde Türkçeniz çok güzel. Tebrik ederim. Arabamın problemi düşük hızlarda kickdown yapıyor fakat hızım 35 milin üzerine çıkınca yapmıyor. hızım düşünce tekrar yapmaya başlıyor.
yardımınız için teşekkür ederim.

sevgi ve Saygılar

[Peter van Es]

…and now, after this short interlude, we resume our normal English language programming…

 

[murat]

Hi Joe,

I cheked my timing again and its ok. 35 degrees BTDC at 3.000 RPM.