tranny question and more.... - PeachParts Mercedes-Benz Forum

rebreath · #1 08-15-2007, 09:26 AM

Slightly confused as to tranny issue.here goes...

been following the tranny thread here and decided to see if I could fix the shifting issue I have.hooked up gauge and checked vacuum....about fifteen at idle.since it was shifting hard i bumped it up until shifting was smooth.worked well but unfotunately the final shift(4th?) still clunks pretty harshly.right now vcv(? top of IP) is set to about 23lbs vacuum.the line to tranny holds vacuum.what would cause that final shift to be so harsh?and why after just a few minutes of driving does it go away?
also....

Having never ridden in a 300D until I bought one I have no baseline comparison for things like ride height,highway vibrations etc.
So here is my question regarding that.I will be in the DC area from the 19th to the 23rd of this month and was wondering if there was anyone in the DC area that feels that their 300D turbo is in good mechanical shape and would be willing to take me for a ride so that I can have a comparison to mine.If so please send me an email with a way to contact you upon arrival in DC.thanks very much

rebreath · #2 08-16-2007, 09:38 AM

no help on the tranny issue,huh

AND

I guess no one is willing to take me for a drive in their car.

dieseldan44 · #3 08-16-2007, 10:31 AM

redbreath,

I think these trannys take a minute to warm up.

when was fluid and filter last done? this would be a good place to begin.

is your EGR disabled? if not, search a bit...you want to eliminate this pesky system as a variable pronto.

does the modulator itself hold vacuum? 23mmHg sounds high to me. The max I can get on mine is 16 mmHg at idle on the tranny line. My master brake line sits at 23 mmHg.

If you are ever in the Boston area Id be happy to take you for a ride in my 300D. I don't have a lot of time in other 300D's, but it should drive nicely on the highway. It shouldn't vibrate much at all...I imagine its what driving a tank at 65mph would feel like.

Ride height can be determined by the camber (slant) of your back wheels. Take a few pics of your car at different angles and post them. Folks will be able to tell you if you are looking ok. Especially take a picture of the rear wheel from about 15' from the back of the car on a flat surface.

dd

rebreath · #4 08-17-2007, 01:38 PM

Quote:

Originally Posted by dieseldan44

redbreath,

I think these trannys take a minute to warm up.

when was fluid and filter last done? this would be a good place to begin.

is your EGR disabled? if not, search a bit...you want to eliminate this pesky system as a variable pronto.

does the modulator itself hold vacuum? 23mmHg sounds high to me. The max I can get on mine is 16 mmHg at idle on the tranny line. My master brake line sits at 23 mmHg.

Ride height can be determined by the camber (slant) of your back wheels. Take a few pics of your car at different angles and post them. Folks will be able to tell you if you are looking ok. Especially take a picture of the rear wheel from about 15' from the back of the car on a flat surface.

dd

hi dan thanks for the response,
fluid and filter less than one year old.no egr connected for about same amount of time.Master brake line sits at a solid 25mmHG and I dont think that modulator holds vacuum.not sure though.
As to warming up,It doesnt seem likely that it is the cause.though it is curious that it stops after just a bit of driving.fluid level is correct.any other thoughts.....

rebreath · #5 08-18-2007, 06:00 PM

no one has any insight as to the tranny issue?been following sams thread and this issue has not been addressed there........anyone.....HELLO!

rebreath · #6 08-19-2007, 09:40 AM

surprised at the lack of assistance here.considering the amount of eyeballs that have looked here(over 100 people).thanks so much for all the usefull info.I guess you guys are more interested in three word stories,and useless banter about how right you are and how wrong someone else is.such a helpful group,but only if one is demure enough.I have always said thank you and used pleases.so helpful.

hey_allen · #7 08-19-2007, 10:04 AM

I hate to add to any flame wars, but in our defense, some of us read the title, and click it, only to find that we don't have anything to do with that model.

Myself, I only have a SD, and little experience with the transmission. I looked hoping to find more info, as I am still troubleshooting mine.

Best of luck in all your wrenching persuits!

rrgrassi · #8 08-28-2007, 02:17 PM

Catch more flise w/sugar?

I grew up w/horses and cows and other animals. Flies tended to gather around crap and dead things. We tried honey and sugar as kids, because that was a favorite saying of my mother. Sugar and honey attracted more bees and ants than flies.

Anywho...Rebreath, please be patient. I do this from work while on break, mainly, and sometimes from home.

About your tranny, IIRC, the modulator is supposed to hold some vacuum. It's the VCV that does the releasing of vacuum. Check the rubber cap and make sure it is not leaking. Hard shifts tend to point to lack of vacuum seen by the modulator, or the modulator could be bad as well. Lots of variables in an automatic tranny.

I do not kiss a$$ either. I know the difference between kleenex and charmin.

rebreath · #9 08-29-2007, 08:38 AM

Quote:

Originally Posted by rrgrassi

Catch more flise w/sugar?

I grew up w/horses and cows and other animals. Flies tended to gather around crap and dead things. We tried honey and sugar as kids, because that was a favorite saying of my mother. Sugar and honey attracted more bees and ants than flies.

Anywho...Rebreath, please be patient. I do this from work while on break, mainly, and sometimes from home.

And it is greatly appreciated

About your tranny, IIRC, the modulator is supposed to hold some vacuum. It's the VCV that does the releasing of vacuum. Check the rubber cap and make sure it is not leaking. Hard shifts tend to point to lack of vacuum seen by the modulator, or the modulator could be bad as well. Lots of variables in an automatic tranny.

I will continue to test and fiddle until I make changes one way or the other.At this point I am leaning more and more towards modulater.will have to replace after I finish moving again!

I do not kiss a$$ either. I know the difference between kleenex and charmin.

me either,that seems to be the problem for so many.It seems that everyone wants more respect than they need or deserve.afterall not everyone has done something worthy of respect.
Only one ass worth kissing,and she shows it to me every day!she who must be obeyed!

dieseldan44 · #10 08-29-2007, 09:08 AM

redbreath,

OK, I'm subscribed to this thread now and Ill take you through this to the best of my ability.

-fluid and filter are OK
-master brake line level is ok

Its time to check if the modulator hold vaccuum. Search for a thread with me and tankdriver, theres an explanation of how to do this in there. Make the prescribed measurements I told tankdriver to do and report back. That will tell us a lot.

My bet is that you have a moderate leak in your central locking system. It takes a while for the vacuum to come up to full since the leak slows the building of the vacuum. Eventually, it does get to the correct level and shifting is fine. BUT, i hate to jump to solutions. Data is needed.

dd

rebreath · #11 08-29-2007, 10:26 PM

Quote:

Originally Posted by dieseldan44

redbreath,

OK, I'm subscribed to this thread now and Ill take you through this to the best of my ability.

-fluid and filter are OK
-master brake line level is ok

Its time to check if the modulator hold vaccuum. Search for a thread with me and tankdriver, theres an explanation of how to do this in there. Make the prescribed measurements I told tankdriver to do and report back. That will tell us a lot.

My bet is that you have a moderate leak in your central locking system. It takes a while for the vacuum to come up to full since the leak slows the building of the vacuum. Eventually, it does get to the correct level and shifting is fine. BUT, i hate to jump to solutions. Data is needed.

dd

last time I tested,modulator was holding vacuum.central lock system held vacuum for the six days that i was out of town.when I get to our new address,i will test again,but I think maybe the mod is out of wack.not leaky just not right somehow.have been packing and not able to pull cover and test adjustment.four days and i will know more.

biobenz240d · #12 08-29-2007, 11:06 PM

My '82 300D has a harsh 4th gear shift for the first one or two shifts of the day then its smooth. You need to get back to the basics.
1. set vcv to 10 -12 " make sure vac drops to 0" at wide open throttle
2. modulator holding vac (done)
3.adjust bowden cable so shifting is about 2500 to 3000 rpms
4. adjust modulator valve out to soften shifts
5.(Should be first ) Change trans fluid and filter add 1 pint Lucas Trans Fix and fill with mercon fluid to proper level
This is the procedure that I followed and the shifts improved with every adjustment. The biggest factor for making it shift like butter is the fluid, filter and Lucas Trans Fix change. Hope this helps . I live in Orchard Park NY, someday we'll get together for a beer.