Tranny fluid change, Bowden Cable adjust, now no downshift?
 

I think I may have screwed up pretty bad. I want to state that pretty much all my experience with trannys has been with manuals. It makes me feel better to say that if I have screwed up.

I'll give all the info here because I don't know whether the cable adjustment or fluid change was the cause.

Changed fluid, including draining the torque converter. When I had the pan off there was a bolt from my valve body sitting in there. I put it back in and turn all the bolts maybe an eight of a turn max tighter. Not much, just a bump. I filled up the tranny and did the P-R-N-D-3-2 thing a few times, checked it and filled it up to the lower line, or so I thought. I wasn't putting the damn thing all the way in. Stupid, I know. I ended up driving it about 30 or so miles and it had too much fluid. Slipping all over in gear changes. I parked it and a couple of days later drained about 1/4 to 1/3 of a GALLON out (it was way above the top mark on the dip stick, WAY above.) And then I put some back in too get the level back up. Or so I thought...

I drove the thing maybe 180 miles before I tried to down shift to slow down. It will not down shift unless I give it throttle at the same time. I checked the fluid, and low and behold, there's pretty much NOTHING on the dipstick. There are no puddles in my garage, where the hell did it go? I put a quart in from a gas station and drive it another 50 miles home. I check it while in park and running and the level looks fine. I look this morning (cold) and now it is WAY above the line. WAY above.

What the hell. Stupid question number one: How the hell do you check the fluid in an automatic transmission? Engine running, in park, in drive? Engine off? When it's cold it should be a little lower, right, and it expands when it is hot, right? Why did it get way over the line when it is cold?

Obviously, I am doing something wrong.

Somewhere in the middle of this I adjusted the Bowden cable all the way out. Post said to take up the slack, well there was still slack (or so I thought) when it was all the way out. I guess these things always have slack because man, it didn't want to shift, it was crazy, like driving a race car. Barely any throttle and I had 4K shifts. Well I turned that down right away. Nice thing about that adjustment is that my strangely fast 2-3 shift pretty much went away and my some what soft 3-4 firmed up a bit.

Second stupid question: Would adjusting the Bowden cable have any affect on my downshifts?

Third question, did I fry my tranny running it low (at least I think it's low, I can't seem to get the level right as it's all over the place) over that many miles, or would it take a lot more. Remember, I added a quart and now the cold level is way over the mark. So if it was low, it wasn't more than a quart low.

I guess I'll throw in a fourth question, but I guess it ties into question #1: how sensitive are these dipsticks? I mean, should I be using a table spoon to fill this thing and check it? Seems kinda stupid to me if it holds 7 quarts or so.

Anyway, this is way too long and I doubt anybody wants to read all this, so I'll stop. Besides, I sure I forgot all the times I checked it and how and what the levels were. This was a two week process I think.

Thanks if you got this far!

Sorry for the novel, I'll shorten
 

Ok, so I wrote just a smidgen too much... So in my bump, I will shorten what I am after:

#1: feel free to mock me, but how do you check the tranny fluid on a 83 300SD? Tranny hot while running, in P, N, D, or engine off? When cold the fluid should be lower than hot, correct?

#2: When my tranny oil was checked with hot tranny and in park (if I remember, I've tried so many different ways), it was barley on the dipstick. I added a quart which seemed to bring it up to the correct level at the time. Now when cold, it is about an inch over the top line. Could I have cause serious damage to my tranny running it at this lower lever for about 180 miles.

#3: Would adjusting my Bowden cable have any effect of my downshifts?

#4: The big one. Why don't I have no load downshifts? It scares me... :(

Thanks, and sorry for the novel.

trans check
 

I can't believe no one has jumped on this thread with something by now. I have a lot of experience with American automatics from years ago, but not much with Benz units. I do know the unit should be checked when hot, idling in park. A lower reading will be attained when cold-maybe a pint down. The Bowden cable adjustment will affect downshifts & upshifts. Not too sure on the correct adjustment, but I'm sure it's close to the full range of the throttle,i.e. at idle-little or no slack & pulled close to limit at full throttle. Also, check your coolant level & condition to make sure the trans cooler inside the radiator isn't leaking & pull the vacuum modulator hose & check for fluid there. If the unit isn't leaking, the only other way it can escape, is through those two ways. So, if your fluid level is suddenly rising, it could be coolant in the trans from the radiator under pressure when off. Hopefully someone with more knowledge on the matter will jump in, Paul.
'84 300CD

To actually know what you have, you must check the ATF while:

1) Hot
2) In park
3) Running
4) Level

Or else you're still just guessing. So remember HIRL when you are sick of your transmission!

Well, I now have the exact same transmission in my car. Check the fluid hot, in Park. I believe the distance between the two marks is only one pint, and this transmission is reported to be quite finicky about the fluid level. I don't know what the fluid level does when the engine is off, but I suspect it rises. Not sure about cold, just check it hot.

What do you mean "no load" downshifts? Mine will downshift from 4-3 if I push on the accelerator, even off the downshift switch in the pedal. Otherwise it will not unless I slow way down. I don't know if it's normal, I'm not familiar enough with the 722.303 yet. But I'm still tuning mine, I'm going to go through the linkage completely, reset the bowden cable and fix and adjust all the vacuum lines. I am also going to add a pint of Trans-X, the tranny is just a bit too sensitive to cold, and the downshift from 4-3 is rough sometimes.

No Load downshift: with pressure off the accelerator, the transmission will not downshift if I throw in into 3 or 2. And I'm not trying to throw it into 3 while going 90, it is an acceptable speed. I would do this while going down hills and such. I tried it while coming up on a car coasting down hill and nothing happened. :eek: That clued me in that something was wrong. Other than that, the transmission had been acting fine.

If I downshift to three like above, and I give it just a little push on the accelorator, it will then down shift.

Strange stuff. So I've been driving the ol stick shift in the truck until I get the Benz figured out. I understand that better!

That is strange. I can shift mine to S and it immediately shifts down. However, my old 722.1xx that I busted never did that. Maybe it had issues already, as it had 250K miles on a OM616 before I put it behind my turbo OM617. I suppose it's damn-amazing that it lasted a whole year before shredding itself.

Sounds like a valve body problem to me. (hopefully) But a problem that MAY go away on its own, especially if you run some trans-x in there. If you took apart an entire valve body, you'd probably be amazed that most of these don't seize up with some tiny amount of contamination. IMHO, the valve body is more complex and certainly closer toleranced than the entire remainder of the transmission. Very, very small deposits of metal powder and clutch material can build up in little dead spots in the hydraulic circuits. Could be that they moved when the trans was over, then under filled. If it is a VB problem, you can get an excellent tested rebuilt unit for about $200 and install it yourself.

Ok, I really feel like an idiot. The best reading I could get while the car was warm looked to be below the low line, about the same distance between the low and high line. I put one pint, or half a quart, of Trans-X in. Drove it back home and now it is above the high line by about the same distance. Still no no load downshifts.

Either I'm a serious moron, something is going on in my tranny, or these trannies are freaky. I'm voting for me beign a moron. I'm getting to the point of beating any pride I might have with a baseball bat and force myself to take it to a shop to have them check the oil!!! :eek: :eek: :eek: I don't think I'd ever be able to show my face in public again if I were to do that... :(

Please be aware that it's very difficult to check the fluid immediately after you add fluid (or Trans-X). It's a very narrow tube and the fluid will stick to the walls of the tube. When you shove the dipstick in there, this fluid will accumulate onto the stick and you can easily get a false reading.

If you add fluid and wish to check the level, first make sure the transmission is hot, the engine is running, and the selector is in park. Then add the fluid and check the level at least six or seven times. Wipe the stick each time. You may see different readings each time you check it. This is because the oil is finally coming off the walls of the tube and you are getting towards an accurate reading.

Don't take it personally. It's a PITA to check the level on these after fluid is added. Far better is to check it, add the fluid, shut it off for several hours, and check it again later (naturally, you need to warm it up again).

Never add more than one pint of fluid at a time unless you are positive of the dipstick level. It's way too easy to overfill these transmissions.

Every time I check it, it's a least half a dozen dips and wipes. After adding the fluid I drove it ten minutes home and checked it again. All while hot, running, level and in park. I have a 100 mile round trip to make in about ten minutes. I guess I'll just take the truck again. I don't want to risk do any more damage to my transmission if it is over filled now.

I know what you mean about the oil sitcking to the sides of the tube. It does make it a pain in the a*$. Dip-wipe, dip-wipe, dip-wipe...

Update
 

In case this sparks any new ideas.

Car still won't down shift. If I'm under 40 and throw it into 2, it will for a second and then shift into neutral (or so it seems, as the engine winds up and then drops off to idle). At that point I can put it into three and it will up shift. Strange stuff.

I did have some correspondence with a Mercedes Dealer service center. The guy and Well, I I guess I can't blame them for telling me exactly what's wrong. They are in the business of working on cars, not telling us what's wrong and how to fix them.

But get this, $239 to drain and fill my tranny! I qouted some AC work too. $168 for a leakdown test and $68 a pound for R12. I don't know what going rates are, but holy *****!

At least with the R12, you can't arque with them, since they've got the right to sell it (but you don't). If they want to charge $200.00 a lb, they can... not that they'd sell much. Around here, most places sell it for about 25-30 a lb, which is why I'll be converting the 134A after my R12 stock is gone.

first
 

your the first guy i have ever heard of wanting the car
to down shift.....

most of us are just trying to get it to shift.....

1. there are 4 items apart from your tranny that effect down shift.

a. the kick down switch under the gas pedal... it wont down shift if
this is broken... so get a new one...
b. the bowden cable must be adjusted correctly... if its too loose it wont
down shift at all...
c. there are little plastic fingers that need to be replaced inside the box
infront of the bowdine cable....
d. there is a vacum shift control on top of the fuel pump... if this thing is not producing vac it will effect the shift as well...


2. Your fluid level is critical....

1.
a. Kick down does not apply as this is just trying to get the car to down shift while coasting in order to decelerate, not accelerate. Regardless, kick down does work.
b. bowden cable adjusted just fine. Like I said in 1.a) nothing to do with acceleration.
c. Those little plastic finger have nothing to do with transmission shifting. I have disconnected all vacuum lines going to that thing. See http://www.peachparts.com/shopforum/diesel-discussion/136132-someone-please-clear-up-me-vac-valves-top-valve-cover-egr-tran.html?highlight=%22transmission+levers%22
d. I assume that is working, although I will have to check. But again, transmission works fine under normal operation, just not when I tell it to down shift while going downhill.

2. Fluid level is finally correct.