82 300SD tranny question - Page 4 - PeachParts Mercedes-Benz Forum

Brian Carlton · #46 08-24-2006, 12:28 AM

Quote:

Originally Posted by SD Blue

Also, check the little rubber cap that goes over the modulator adjustment. It is my understanding that this is part of the seal and if it is cracked or missing will give you a vacuum leak.

That's the first thing to check!

Samuel M. Ross · #47 08-24-2006, 02:12 AM

on your 1982 300SD it does not appear that the plastic cap comes off like on my two earlier 1980 models. I'm guessing that yours is a "FEDERAL" [not a "CALIFORNIA" car] and so according to one on-line parts listing yours most likely has a GREEN plastic cover [that does not appear to be removable] and on this colored cover there is a black rubber/plastic access cap that allows you to adjust the modulator... and yes as previously instructed, this must be looked at closely to see what kind of condition it is in. If the cap is bad, I hope you can order this separate from the $40+ modulator [see you DEALER parts dept.].
I must now defer to others who know more about this later model.
To get an advance idea of what the modulator looks like, go to these links :
Their parts blowup for the tranny at:
http://www.performanceproducts4benz.com/Drawings.aspx?bmid=97
which shows the modulator as #7...
and a closeup of the modulatior at:
http://www.************************/Productpage.aspx?pid=104193&name=Modulator%20Valve&part=
which shows it with a RED plastic cover [yours is most likely GREEN if it is FEDERAL... RED if by chance a CA car].
I do not have first hand knowledge of this later model modulator so I must defer at this point to those who do [ Brian and others]

I just thought the graphic and photo of the part might help you when you eventually get your head under the car.
[ Make certain for SAFETY that you use a stand in addition to a jack]
Sam

cjl1973 · #48 08-24-2006, 07:50 AM

I'm actually hoping to find some ramps, and I know I have something I can block the back wheels with as well.

Samuel M. Ross · #49 08-24-2006, 11:12 AM

but depending on the type, you might anticipate a problem where they tend to slide on you as you try to drive up onto them. This was the case for me when using a set of steel ramps. The solution was to place them against a section of uneven concrete at the entrance to the garage to prevent the sliding... if the garage door heigth allows. If you are purchasing new, inquire about this being a problem. If used, ask the seller the same thing.

Sam

SD Blue · #50 08-24-2006, 11:30 AM

To keep the ramps from sliding, here is a trick that I found to resolve that problem. Place the ramps immediately in front of the tires and give them a swift kick to wedge the ramp under the tire. (Be sure the little rubber foot on the bottom is in a good dry spot.

)

Samuel M. Ross · #51 08-24-2006, 01:03 PM

made me realize that I failed to think of a likely, if not obvious, solution for my sliding ramp problem... namely a sheet of rubber placed between the ramp and the driveway.
Sam - Safety Engineer thank goodness for others a " Retired " engineer !

SD Blue · #52 08-25-2006, 09:53 AM

Quote:

Originally Posted by Samuel M. Ross

............solution for my sliding ramp problem... namely a sheet of rubber placed between the ramp and the driveway............. !

I believe you've got it! Something as simple as inexpensive, rubber floor mats (the kind that say Welcome

) may be the solution to "slip sliding away".

cjl1973 · #53 08-28-2006, 10:12 PM

Now that I have a 1.5 ton floor jack and a pair of jack stands I think I'm ready to start. My thinking is to follow the vacuum line from under the hood to the transmission, and see if its even connected, then inspect the little cover on the modulator. If its not connected, reconect it, and see if it will hold vacuum. If not, I'm thinking that I need the modulator, and may as well just replace any gaskets, and the little cover at the same time. If it is connected, then I will also know that its time for a new one.

Assuming that I need to replace the modulator, what do I need to do? Empty the transmission fluid first? (I'm sure it can't hurt to do the fluid/filter thing, at the same time.) What kind of tools am going to need to do these two things, how much ATF should be in there? I know not all of it going to come out, but should I expect to need 4 quarts? More? Anything that I should know? I have never done this on any car before.

Samuel M. Ross · #54 08-29-2006, 02:41 AM

yes you will have to drain some fluid so it might just be goo to plan on doing a fluid & service at this time... including draining the torq converter.

For tranny fluid capacities, take a look at:
http://www.peterschmid.com/images/capacities.jpg
Now that I take a look at this I'm not certain but I think by "Oil Change" they might mean draining the transmission pan only... and by "Full Capacity" they mean pan and torq converter. Would someone else please take a look at this and confirm what the proper capacities are. I just recently did a 722.1 tranny and I'm almost positive it required 6+ quarts.

I'm off on a 2-week extended family visit and might not be able to participate in this FORUM until I return. I won't know until I try remote participation!??

Sam

anhydrous7 · #55 08-29-2006, 09:00 AM

CJL1973, just out of curiosity, whas the shop European Imports? I purchased a 1982 300SD back in 2001 from an individual that claimed it had a bad transmission. He was told this by European Imports. They estimated it would cost $3500 to $4000 to R & R the transmission. He did not want to spend that kind of money, so he advertised it in the Post Disgrace. I bought it after driving it for less than half what they were going to charge him for a new transmission.

I got the car home and the first thing I did was clean the calibrated orifice running from the main vacuum line and tee'd off to the modulator. Turns out that orifice was partially clogged and causing all of the hard shifting problems. The car had 135,000 miles on it when i purchased it. It now just turned over 200,000 miles this past weekend with the same transmission. The only onther thing I did to the transmission was service it. I highly recommend using a snythetic transmission fluid when you service it. And don't for get to drain the torque converter when servicing the transmission.

Good luck!

SD Blue · #56 08-29-2006, 10:43 AM

Considering things as they are, it might be best to wait on the filter change for the tranny. I say this only to keep from entering the possibility of another factor in your shifting problem.You will need to only drain the pan (drain plug), which is only just a little over 2 quarts of fluid, for modulator replacement.

But the modulator replacement should only be done AFTER all of the vacuum issues are sorted out. (I am telling you this from experience.) Changing the modulator is a little more involved than plug-n-play and there is no need to create more work and frustration.

cjl1973 · #57 08-30-2006, 12:12 AM

The vacuum thing seems good at the moment, except for up to the modulator, which I have not had a chance to even look at unfortunately. Since I only have the defroster vents, I'm assuming that there is a leak in the CC as well, but that is the only one I have been able to figure out. However, I was wondering if I could just disconnect that and plug the line to it? Would I still be able to turn on the defroster? I'm assuming I have heat, since I turned on the CC, and hot air blew out, and then got hotter, although its tough to judge when its 103 degrees outside.

The plug only fluid change is probably a good idea, get one thing worked out at a time. Makes things simpler to troubleshoot, if needed.

Samuel M. Ross · #58 08-30-2006, 01:09 AM

it is essential that you have a firm appreciation of how "CRITICAL" it is to resolve the vacuum issues before you dive into modulators or internal tranny guesses. To do otherwise is truly getting the "Cart before the horse". I hope you heed this well intended advice. See my THREAD on this very subject... at: It's CRITICAL... how you set your transmission's vacuum system on your diesel MBZ...
Yes, find and resolve the leaks and then make sure you have the basic vacuum parameters being delivered to the vacuum modulator line BEFORE you even touch any modulator adjustment.
Best regards,
Sam Ross

Samuel M. Ross · #59 08-30-2006, 01:14 AM

Quote:

Originally Posted by cjl1973

The vacuum thing seems good at the moment, except for up to the modulator, which I have not had a chance to even look at unfortunately. Since I only have the defroster vents, I'm assuming that there is a leak in the CC as well, but that is the only one I have been able to figure out. However, I was wondering if I could just disconnect that and plug the line to it? Would I still be able to turn on the defroster? I'm assuming I have heat, since I turned on the CC, and hot air blew out, and then got hotter, although its tough to judge when its 103 degrees outside.

The plug only fluid change is probably a good idea, get one thing worked out at a time. Makes things simpler to troubleshoot, if needed.

What is meant by "defroster vents"... and "... leak in the CC..."??

Sam

Samuel M. Ross · #60 08-30-2006, 01:15 AM

Quote:

Originally Posted by cjl1973

The vacuum thing seems good at the moment, except for up to the modulator, which I have not had a chance to even look at unfortunately. Since I only have the defroster vents, I'm assuming that there is a leak in the CC as well, but that is the only one I have been able to figure out. However, I was wondering if I could just disconnect that and plug the line to it? Would I still be able to turn on the defroster? I'm assuming I have heat, since I turned on the CC, and hot air blew out, and then got hotter, although its tough to judge when its 103 degrees outside.

The plug only fluid change is probably a good idea, get one thing worked out at a time. Makes things simpler to troubleshoot, if needed.

What is meant by "defroster vents"... and "... leak in the CC..."??

Sam