Transmission won't shift in cold weather

[waltb2000]

Recently, when it's real cold out (below 15 degrees) the tranny on my 1983 300 SD won't shift from 2nd to 3rd, and sometimes even from 1st to 2nd. When it's warmer out there is no problem at all, and strangely the problem seems to worsen the longer the car has been running. About 5000 miles ago I was having slippage problems and had the screen filter and fluid changed which completely cleared up the problem. During that repair, they had also added some Lucas Transmission Fix to the tranny fluid. What I'm thinking is that maybe this stuff is gumming up in the cold temps and that's what's causing the shifting problem? I checked the dipstick while the engine was warm but the fluid was no thicker than the ATF in the bottle that had been sitting in my trunk. Should I drain all the tranny fluid to get rid of the Lucas stuff and then refill it, or does someone have any other suggestions? I'm not familiar with this Lucas product. Is it a varnish remover like TransX or is it something else?

Thanks!

[mplafleur]

I once had the same problem. While cold, the car would slip while going into 3rd gear. Once warm, it had no problem. The fault was a vacuum leak. I didn't fix it so I can't say for sure what part it was.

[Pato]

Hi. I figured i would ad to this post since my problem is related almost....

Mine does the opposite (bythe way 250K+ miles on car). it shifts fine for the first 10 mins of driving. then slips and flares and all that fun stuff. doesnt really like going into 4th. also the problem seems to go away (though only works in low speed) when i shift to "S".

I have not tried transX or vac sys diagnosis. One mechanic tested just one of the pressure points and said it was fine and that it was time for a new tranny. So...i wish I could help you, but maybe someone on here has some knowledge about this.

thanks
Pato

[Pato]

thats the car i referred to in the last post

[123]

on my 190d the tranny shifted ok, but not as smooth as my 240 so i had the tranny flushed and renued and they put some conditioner in now it shifts smoother, but some times when the engine reached 85deg but the oil is still not completely warm i guess it slips on low speed going into 3rd a little, when stone cold or properly warmed up its ok