Ok. So I'm reading about testing the transmission modulator. Jack up the car and all that jazz.

Here's the question. When I pump down the vacuum line (black goes down to trans just behind air filter) I get it holding a steady vacuum. Soooooo... what else is there for me to "test" in this department. Is there a reason that they say to disconnect the line and test the modulator right @ the trans? What am I missing?

Thanks again, Pete

I suppose they say to remove it in case it is leaking, then you'd be testing solely for a leaking modulator. Since neither leak you don't have to worry about that. Next I'd check the vacuum signal which goes to the modulator. What is it at idle? How about at WOT? What is wrong with the shifting?

__________________
Jeff M.
Mercedes W123 DIY pages are now located here.
1983 / 1984 300D Sold
2000 CLK430 Cabriolet ~58k Sold
2005 Avalanche 4x4 ~66k

Thanks Boost,

Right now I realized that I am peeing into the wind until I fix the rest of the vac system or isolate parts that leak. (plug them for now). The vac system seems to be VERY particular when it comes tot he transmission. Right now I get some "flaring" (if that is what it is calle when the engine over-revs prior to shifting).... but a vac leak I thought I had fixed is now leaking in a different place (I'm chasing the leak) lol...

I should have some time over the next few days to tinker more. I was lucky and had most of the weekend to play with the car... got a TON of stuf done... but I don't think I'm going to do more until the under-the-hood vac. is the way I want it. I want to get it right, and adjust the trans 100%, then I'll change the trans fluid etc. There is no point in going beyond if I have to pull the trans...

Thanks again... I'll keep you in the loop!

Have you tried a Trans-X treatment ?

leather,

Not yet. But I have read about all the different "additives" that people swear by. My course of action is to try and do all the "adjustment and maint." things and when/if that fails... take it to the "additive" level...

That's my plan... if you have a better idea... let me know. :-)

Pete

You have mentioned some symptoms.. but no amount of adjusting at those places you assumed would affect those symptoms will have any affect if the problem lies in varnish build up in the auto trans valve body...
If you are sure your fluid is clean,the right amount installed , the valve body holes are clean ( have used the Trans-X) and you have a new filter installed THEN you have a good chance of adjusting and tweaking by the items you were focusing on.. but not until then...
It is cheap, like under twenty bucks if you use two cans as it may suggest for your amount of fluid... and is easy to do... and many on this site , including me, have had dramatic immediate results... so little risked... and potentially much to gain...

Ahhh... Thanks!!! NO! I have not done a filter/fluid change! So I guess I know what's on my list now! (high)!

Pete

Get a clear tube which will fit the trans dipstick tube.. and siphon out more than one quart.. then put a can of the trans-x in and drive the car a couple of hundred miles... unless it clears it up like immediately... then change the fluid and filter and you will have gotten rid of that varnish dissolved into the fluid by the trans-x...

Question:

Are you saying to do a drain and filter job on the trans. Refill with transfluid + 2 cans of Trans-X... to equal proper level (obviously) and then what? Run for a couple of 100 miles? drain, and put good ATF? Also, when/if I do the second drain (to get the two cans out(???) I assume I do another filter... correct?

The reason I ask is I want to order the filters... and I want to make sure I get the right amount.

Thanks,
Pete

LOLOL We posted at the EXACT same time!

Thanks!!! I can use my MityVac to suck the fluid out.

Pete

Correct can I am looking for?

First find out how much fluid your trans holds..
then go to the parts store and look on the side of the trans-x can ( it is brilliant metallic blue)
My wagon had enough fluid capacity in the trans that the can called for using two cans of the trans-x..
It costs about $8 per can...
So I just suggest taking out enough through the top tube to put in the right amount of Trans-x....
then start the car and sit in the driveway and ' run the gears' about a minute in each... up and down including park... at high idle on all this process...
This by itself may show a lot of improvement.. we are talking about 10 -15 minutes of this... if not... then drive a couple of hundred miles...
Then change everything out... fluid , filter... and I see nothing wrong with putting one can of trans-x back in with the new fluid on these old cars...

Yes, that is the brand name... but the cans I get are squatty like old style oil cans...

Simply awesome!!! Thanks for the replies!!!


Pete

The trans X I bought a while back (which didn't fix the problem, even with mobil1 syn in the tranny) came in this funky looking plastic container, I think it was about $8 at autozone. The cap is what looked odd, the container almost looked normal. Isn't ~8qts normal?

I bet your problem lays with getting to much vacuum at the tranny at normal throttle. If you were to take the linkage off the IP bleeder valve (white-ish) and run the arm 10mm to the stop it should be from 5"-6.5"hg. It should be 0" at WOT, 15-18" at idle (with linkage on). If you can't adjust the bleeder valve to these values (there is a nut under the cap to adjust them) then you may be on the same page as me, have to fork out $142 for a new one. What speed does it generally shift into last gear? For all testing purposes I'd say check the EGR control valves for leaks then just disconnect the line going into the cab (w/o breaking that line ) if you suspect leaks there.

__________________
Jeff M.
Mercedes W123 DIY pages are now located here.
1983 / 1984 300D Sold
2000 CLK430 Cabriolet ~58k Sold
2005 Avalanche 4x4 ~66k

Boost, thanks for the ideas.

People tell me I'm waaaaay to hung up on the vac system on this car. But I *HAVE* to say that based on what I know it seems that vacuum is really the key to just about the whole darn car!!! Think about it!!! aside from spining the wheels... it really is key!When I got my car the vac pump was literally at ZERO. I had nothing. No brakes, no shut-off, and the car ran like crap. Little by little the car is running to the point where I think it is awesome. Once I deal with this transmission issue, the rest is just cosmetic and minor fiddling that I can do anytime I dam-well please!

Thanks agin for the tips. I assume you're talking about this part when you say the white-ish thing:



Correct?

I *DO* need to test this! (If you know how... let me know... else I'll search and look in the books)

Pete