Hi,

I took my 300sd to the car was yesterday to spray off the engine. Now the trans is flaring and the kickdown switch is not working. What gives? Please help because it was perfect before!

Dieselman

I've heard the word "flaring" refering to automatic transmissions and I don't know what it means.

Just what does flaring mean?

P E H

Check my web site here for what goes where on the 1983 300SD. They vary from year to year - not sure which year you have.

Focus on connections around and on the vacuum control valve on the injection pump (driver's side of the engine) and see if you have any vacuum hoses disconnected. Also check under the car and verify if the vac hose is connected to the transmission, next to the vacuum shift modulator. Your car should also have a vac house routing diagram on the cross piece at the front, visible when you open the hood, on the passenger's side. That will tell you what goes where.

Also check for fractured vac hoses - these get brittle and fragile with age, so just because everything is plugged in doesn't mean one of the hoses isn't broken. I give the part # for replacement hose in my piece.

The tranny is vacuum controlled as regards shifting and a disconnected hose would be consistent with your chronology.

....to a very slow shift (most commonly from 3->4 on the 722 tranny) where you hear the engine race up 50 or so revs before finding gear - rarely enough to register on the tach but clearly audible - and will result in premature wear to the bands in the tranny.

Thomaspin,

That is what my '79 300SD does if I let up on the accelerator before transmission shifts into high gear. If I hold the pedal steady it doesn't do it.

P E H

Hello again I found the problem finally. It was a little metal rod on the side of the alda with a plastic looking clip on it. It was off and hidden from view. I was getting pretty nervous. The clip is broken and I do not know how to really fix it. I stuck it back in the hole and so far it has stayed. Totally fixed the problem! I dont think it was related to the engine wash now. I found another problem though the water pump seems to be seeping a little. Should I change it immediately or not worry about it.
Thanks
300SD is alive and well at 212,000

Paul - that suggests your part throttle shifts are too late and you may wish to tension the Bowden cable a tad - try one turn counterclockwise - that will get you an earlier shifts at part throttle and should reduce flaring/wear. A CCW click or two on the vac mod at the tranny may also help, but may make your other part throttle shifts too firm. If that does not work, maybe reduce the idle vacuum at the idle control valve - Steve B says that 12" on a worn tranny is not unusual. I'm running 15" but the tranny was overhauled 60k ago. The adjustments interact and it's more art than science - idle vac, Bowden and tranny modulator.

Dieselman - I suupose the cynical answer to the water pump Q borrows Clint Eastwood's words - "Do you feel lucky?" The pump will eventually fail and you may even notice the water temp rise into the red zone before your engine blows. That may be today....or in 2 years time.

The water pump on the 5-cyl is not only exceptionally cheap (get a reman MB with core exchange, not one of the poorly made after market ones - I paid $30-40 net to Fletcher Jones (MB dealer - CA) a couple of years ago for mine) it is also very easy to change, unlike on the V8s - bet there's a lot of threads on this site already. I would change it. Back when I last did it I had no digital camera - maybe in 5 years time?

Congrats on the vac fix on the ALDA.

I'm not sure if this is flaring, but the car dosent move (the engine just revs) untill the engine is at about 1075rpm. It only does this in 1st gear from a dead stop.

82 300td

First thing to check with that is the transmision fluid level.

Thomaspin,

I have '78 '79 and '80 300SD and they don't have a Bowden cable. I think this started ib the '81 models.

There is a rod that runs from the throttle linkage to the transmission that affects the shifting depending on how far the accelerator is depressed. I think that by adjusting this rod for earlier upshifts, I can eliminate some of the flaring because I won't have to let up on the accelerator to get the transmission to upshift.


P E H

I know I'm supposed to check the trans. fluid with the engine onn and in park, but I cant get an acurate reading. It only shows a useable mark with the engine off. It diddn't start doing the first gear "flare" untill I put too mush fluid in it once for about 3 days (45 miles). Now I have changed the fluid and filter and it still does it.

My 300D (78) was doing that, and replacing a badly worn bushing on the shift linkage fixed it