85 300D Transmission vacuum settings - PeachParts Mercedes-Benz Forum

snookwhaler · #1 10-31-2009, 05:21 PM

I have been reading links and searching for a while now and cannot find what I am looking for. Maybe someone knows the answer?

A few months ago I adjusted the vacuum on my 85 300D to try and compensate for the common 2/3 shift flare. I adjusted the vacuum at the saucer and then again at the VCV. I think I wound up setting it at around 9 or 10 in. at the VCV. This corrected the flare when warm. But, when cold the flare is still there.

I plan to install the K1 spring kit this coming Thursday afternoon. I cannot remember my original vacuum settings at the flying saucer or the VCV prior to adjustment? I think they were around 12 to 14 in. My question is this.... Is there a good place to start adjusting the vacuum down? Should I just put it back at 12 or 14 in. and watch for the drop to zero from there? Or should I just leave it alone at 10 in. and dial in the modulator after installing the kit?

Also, what vacuum readings should I be seeing at the saucer versus at the VCV?

Brian Carlton · #2 10-31-2009, 05:27 PM

What's the situation with the other shifts when warm? How's the 1-2 and 3-4?

If they are tolerable, just reduce VCV vacuum further. There's no magic in 10". I've got the SD dialed down to 8". All very crisp shifts.

snookwhaler · #3 10-31-2009, 05:35 PM

Brian,

When cold the 1/2 is neck snapping firm, the 2/3 has a slight flare (not much) and the 3/4 is firm. When warm the 1/2 is firm, the 2/3 is normal and the 3/4 is normal. The 3/4 is the same pretty much all the time.

My thinking is that (hopefully) the K1 kit will help cure the 2/3 so I can back off the modulator a little to soften the 1/2. Not really sure though.

I was not sure where to start with the vacuum. I remember it being high when we talked about this before. I remember taking it way down. I'm pretty sure it is around 9 or 10 right now.

Brian Carlton · #4 10-31-2009, 05:45 PM

Quote:

Originally Posted by snookwhaler

My thinking is that (hopefully) the K1 kit will help cure the 2/3 so I can back off the modulator a little to soften the 1/2. Not really sure though.

I was not sure where to start with the vacuum. I remember it being high when we talked about this before. I remember taking it way down. I'm pretty sure it is around 9 or 10 right now.

Let's hope you are right. The shift combinations are not good at present.

I thought the '85 had a different spring to soften the 1-2 a bit??

Start with what you have.........and adjust from there. If the 2-3 flare disappears completely, increase vacuum slightly to soften the 1-2 to a tolerable level........but, remember, there is no magic here.........the transmission is still getting old and you cannot keep the flare at bay forever.

snookwhaler · #5 10-31-2009, 05:48 PM

Yep..... I'm worried.

Thanks for the input on the adjustments (again)! I report back what happens on Thurs.

snookwhaler · #6 11-06-2009, 09:37 AM

I have the pan off and I'm wondering if I should put a hard drive magnet in there before I button it up?

Just about every auto. trans. I have worked on in the past has a magnet to capture debris in the oil. This one does not.

I was in a hurry the last time I changed it and did not even notice.

snookwhaler · #7 11-06-2009, 05:07 PM

I got the spring kit in there. It shifts much better when warm. I'll check the cold shifts in the A.M. In the morning is when I had the bad 2/3 flare.

I have not messed with the vacuum yet. Current vacuum down to the Mod. is 9.5 and goes to zero at WOT. I may raise it a little tomorrow, then soften the shifts at the Mod. and see what happens.

I didn't get any feed back on the magnet. I placed it around the drain hole on the inside of the pan, blasted the pan with Brake Kleen and compressed air and put it and the old seal back on there along with 6.2 qts. of Dex III.

It was worth the $$ to do this...

Brian Carlton · #8 11-06-2009, 05:12 PM

Quote:

Originally Posted by snookwhaler

It shifts much better when warm.

Explain please.

In the OP, you stated that it was OK when warm...........no flare??

snookwhaler · #9 11-06-2009, 05:24 PM

Quote:

Originally Posted by Brian Carlton

Explain please.

In the OP, you stated that it was OK when warm...........no flare??

I have not had a chance to check the shifts when cold.

It was already warm when I went for a drive to check the shifts. What I meant is that the 2/3 shifts much better warm now than before. Overall the shifting is much better.

Brian Carlton · #10 11-06-2009, 05:27 PM

Quote:

Originally Posted by snookwhaler

What I meant is that the 2/3 shifts much better warm now than before.

Yes, I got that.

However, there was no mention of any problems with regard to warm shifts, other than the typical harsh 1/2?

If you didn't have a problem, I'd like to know what is "much better"?

snookwhaler · #11 11-06-2009, 05:34 PM

The 2/3 obviously had a problem when warm before the spring kit. I thought it was OK.

Now with the spring kit in there.... The 2/3 is shifting much better. By better I mean quicker and harder. Before it would shift OK when warm (compared to now). What "I thought" was Ok was obviously not right. Now there is a positive engagement where before it was weak.

Now, the 1/2, 2/3 and 3/4 shifts all shift about the same firmness and speed.

Brian Carlton · #12 11-06-2009, 05:57 PM

Quote:

Originally Posted by snookwhaler

The 2/3 obviously had a problem when warm before the spring kit. I thought it was OK.

Now with the spring kit in there.... The 2/3 is shifting much better. By better I mean quicker and harder. Before it would shift OK when warm (compared to now). What "I thought" was Ok was obviously not right. Now there is a positive engagement where before it was weak.

Now, the 1/2, 2/3 and 3/4 shifts all shift about the same firmness and speed.

Well, that does sound excellent. I'll bet your cold problems will also be solved.

snookwhaler · #13 11-07-2009, 04:10 PM

Quote:

Originally Posted by Brian Carlton

Well, that does sound excellent. I'll bet your cold problems will also be solved.

Yep! Problem solved.

This is a serious relief. Thanks again for the help Brian!

Brian Carlton · #14 11-07-2009, 04:35 PM

Quote:

Originally Posted by snookwhaler

Yep! Problem solved.

This is a serious relief. Thanks again for the help Brian!

Excellent.

Just for clarification.........you only replaced the K1 spring..........did NOT purchase and install the Superior Shift kit???

snookwhaler · #15 11-07-2009, 04:59 PM

Quote:

Originally Posted by Brian Carlton

Excellent.

Just for clarification.........you only replaced the K1 spring..........did NOT purchase and install the Superior Shift kit???

That is correct.