She just won't move??!!
 

Okay, I'll explain the situation and the outcome.
I have a 91 350SD that I just pulled the 3.5 out of and put in a 3.0. Just got it all hooked back up on Friday. Fired right up without hesitation. Let it run a little added fluids as it started warming up. Got in put it in drive went forward, put it in Reverse went backwards...did this a couple times. Checked the transmission fluid while it was still running, a little low so I added some, maybe a tad above the full line. Got back in the car (it had never been turned off since I was driving back and for the and then added transmission fluid) put it in drive....nothing, revved up the RPM's, no movement. Put it in Reverse....nothing.
If I put it in Park the transmission goes in Park like it's supposed to, when I put it in Reverse or Drive there is no engagement and I can roll the car like it is in Neutral.
I did not replace the transmission or adjust the Bowden cable when I removed the old motor. But I don't suspect the Bowden cable as I drove it back and forth in the driveway with no problems and now nothing.
Any suggestions or ideas?

Are you sure your shift linkage is connected correctly?

The linkage never was disconnected. But I did check to make sure nothing came unhooked.
But, as I said, I had been going back and forth in the driveway without difficulty and then nothing. No pop or clunk.
I'm leaning more to a vacuum problem but if it is bad enough to not allow the transmission to shift would there not be other vacuum problems?

Torque converter bolts all properly installed? If you left them out by accident (I've done stupider things myself), there may have been enough "drive" by the lugs touching to move the car a little, then it finally started to slip too much.

Has to be something similar. It's definitely not a vacuum problem.

^^^ Agreed. Did you use the original torque converter? If not maybe the replacement one is different. You should pull the cooler line to see if trans fluid gushes out while running. Be careful, you'll make a big mess.

Mine did that, and it was a sign of impending doom
 

My '81 is still in the tranny shop being rebuilt. (they had to get a couple of parts from the MB dealer) What I found when mine wouldn't move is the filter was clogged. I went through a couple of cycles of cleaning the pickup screen (and changing the filter once), putting all new fluid in which would fix it for a week or so, but in my case the bands/clutches were disintegrating and clogging the filter with tiny bits of friction facing material.

I'm supposed to get mine back from the shop on Friday.

All the bolts are in but I did use the torque converter from the 3.0 motor. So it has the original transmission that was in the 91 350SD but the torque converter came out of the 87 300SDL with the motor.
I completely drained everything and put in a new filter and gasket.

Maybe the torque converter still isn't full of ATF? Maybe there was a big slug of air that went through the system, including in the valve body?

I did the same conversion but we had no problems like this...Bit of a heads up though, if that 3.0 was sitting for a while, don't be surprised if it drives EXTREMELY slowly at first. The performance will improve over time.

Are you sure the torque converter is seated in the front pump properly? Maybe the ears that drive the pump are not engaged? Plumb a test gage in and check line pressure. The car I had with the "no drive" symptoms had those little drive ears sheared off the torque converter, thus no pump pressure.

I am going out right now to see if I can make a mess in the driveway (not that you can tell) by unhooking the line to the cooler and see if I have pressure.
The motor is great. It came out of a perfectly running 300SDL. The one I put in my wife's 300SD had been sitting for a long time. It smoked and drives slowly up the hill. But she loves driving the speed limit and taking 20 minutes to get up to it. It's gradually getting better.
I'll let you know how the pressure line goes.

Well, the good news is I didn't make much of a mess in the driveway.
The bad news is, there was no mess because there was no pressure from the line going to the cooler.
Tell me I don't have to pull this entire motor out again.

You don't have to pull the motor out. You can pull the transmission.

Do you think I should use the other torque converter?
I used the one from the donor vehicle rather than the one that was on the receiving transmission.

You need to find the problem first. My thinking is that it is going to be either the TC and/or the front pump. Pull it out and let us know what you find....:eek:

Okay, the rain finally broke so now I can get back to my hobby.
The torque converter spins fine with the flex plate, no problems there. I definitely do not have pressure.
I don't know how the tabs could not be lined up with the pump if it went together so easily.
If I do have a "big slug of air" how would I bleed that out?
I am ready to drain the fluid, drop the pan and recheck the filter to make sure it was seated properly.

Some questions:
1. Why did you change the torque converter at all?
2. Are you sure the two converters are 100% interchangeable?
3. When you installed the converter, did you fill it with fluid first?
4. When you installed the converter are you sure it was completely seated in the front pump, exactly the same distance from the front edge of the transmission as the old one?
5. Did you replace the front pump seal?
Just some things to think through, and the answers to these questions might help us to pinpoint the problem. I'm leaning toward the diagnosis that the torque converters LOOK the same but they are not interchangeable. If you have researched that angle already, then we could look at either improper installation, or the unlikely (IMO) that your front pump simply picked this time to fail.

Someone else asked but I didn't see an answer - did you install the 300 torque converter dry? Did you drain it before removing it?

At this point I'd drain the tranny and torque converter and make sure at least 7 quarts goes back in.

Sixto

I put the two converters side-by-side and they were identical. I didn't know if I should go with the one that came with the motor or the one that came with the transmission. I decided to go with the one that matched the plate.
I drained the TC before putting it in. I just got in from draining the transmission and removing the pan. Everything looks okay.
But I will also drain the TC and then start over from that point, before dropping the transmission and starting over even further in.

Stall speed can vary between identical looking torque converters. I'm sure there are other parameters that can be different as well. The differences between 300 and 350 torque converters wouldn't be significant enough to cause the issues you're having.

Sixto
87 300D

Were you able to drive the donor car before you did the swap? Is it possible the converter you put in was bad and you had no way of testing it? After reading your original post, it seems you did add fluid as needed, kind of seems unlikely it is just low on fluid. If the converter was empty, the pump should fill it, thus lowering the fluid level in the pan, I would think, so you would notice low fluid when you checked it. I don't know if it is possible for the pump to "lose its prime" so to speak if the converter was completely drained, but it doesn't make sense because I have never heard of anybody having these issues with a fluid change when they drained the converter as well. Maybe an obstructed (or defective) filter?

Yes, I drove the donor car home on the freeway, it ran beautifully. What a ride (350SDL) compared to my 350SD. Smooth!!!!!
I just drained all the fluid from the TC and am in the process of checking over the filter. Getting ready to button it all back up and try it out.

I would have used the 3L torque converter on the 3L engine also. Its stall speed is likely matched to the output of the 3L engine, not the lower power curve of the 3.5L.

Good luck, I hope you get it ironed out.

I sure hope the fluid change works. The problem really has to be related to changing the converter or filter, since both transmissions were functioning just fine before the swap and the only things you have changed on the trans is the converter, the fluid and filter.

ARRRRRRGH!!!!! The fluid change didn't work. I still have no pressure and no movement at all.

I have to work for the next 48 straight so hopefully Sunday I can get to it. It's probably better that I have a couple days away from it.
I'll drop the transmission pull the TC off and put the other one it.

By the way, yes, I did replace the front seal.

Well, it looks like you have narrowed it down to one of two things, either the front pump is not being driven by the drive lugs on the torque converter hub, or the pump has failed completely. At least you have another trans that works if you have to swap them.

I just wanted to be done!!! I have to put a new Injection Pump and pull and clean the injectors in my sons Dodge 250.

I am using my Dodge 350 as a commute vehicle. At least with the Gear Vender it gets 28mpg. And on biodiesel it's not so much the fuel as it is the beating I take going down the freeway.
I miss my Benz!!!!

Hopefully it is a simple thing like the torque converter is not seated properly in the slot and all other things are good.

was it working before the engine swap?

If was doing it before the swap then its something with the tranny but if just started now then you messup somewhere and need to retrace your steps

looking at some bulletins could be a few things. To see if your oil pump is working put the car in P then D and loosen the lines to the ATF cooler in radiator and see if ATF comes out if it does not then you have found your problem

You may have a stuck shift valve in the valve body of the tranny

It worked fine before I pulled the motor. So I'm assuming I didn't put it together right. I will drop the transmission and start over.
I have already done the P and D and removed the line to the cooler and no pressure. It just dribbles out.
I'm sure it's just not lined up right. Somehow I got it together regardless.

Check back here next week for an update. I won't be able to get to it until Sunday or Tuesday.

Question
 

How much fluid did you put in the transmission?

If the converter/pump is air cavitating = no output pressure = never install an empty/dry converter.

I put in 7 qts. and it's showing half way up the entire dipstick. So it appears that not much is getting into the TC.

When I drained it yesterday, to kind of "start over", I would say about 4 qts came out of the TC.

Do you know of any other checks or tests to run to determine if the problem is the pump or improper installation?

I am going to drop the trans out and replace it with the other TC (fill it first), but I would hate to get it all back together and find it still does not pump. I do have the other transmission off the 87 350SDL, I guess I could just swap the trans out completely.

I believe there is a plug on the side of the trans where you can plumb in a pressure gage. I don't recall which one it is, maybe someone on the forum knows. You should have pump pressure anytime the engine is running, regardless of shift selector position, as I recall. Mercedes calls it "working pressure". If you don't have pressure, either the pump is not being driven or it is not pumping. I believe improper torque converter installation could damage the pump rather quickly. Maybe another forum member has some more insight or more ideas, but I think it is time to put the known good torque converter into the known good trans and install them in your car. If the pump has been damaged it may send metal through the rest of your trans and cause it to fail soon, even if you could just reseat the converter and make it work. If you put your other converter in the car and damage it you will have to buy a converter, plus do a trans swap.

Here's the update so far.

I dropped the transmission. Nothing amiss, but I went ahead and pulled the TC. Drained and filled the other first. Made sure it was seated, lifted and slid it into place. Bolted everything back up, fired it up. Let it run for 5 minutes or so....still no gears. If I rev it up pretty high, the wheels start to turn but I can stop them with my hand.

Checked the pressure, still nothing. Not even idle pressure.

So, I guess the next step will be to take the transmission out of the 87 300SDL "parts car" and put it in the 350SD.

Any tips or pointers I should know before I take on this swap?
I have never done a transmission change out.

I'll keep you updated.

You say you "lifted and slid the converter into place" Did you turn the converter while installing it and feel the pump drive lugs engage the slots in the front pump? If the drive lugs don't engage the pump you will still have no pressure. If this is not the problem, your front pump has probably failed and it is time to change the tranny. You may end up going with a new converter now, because usually front pump failure will contaminate everything downstream, and it is about impossible to remove all the contamination from the converter. That's why I had advised not to put the other converter in this tranny. The surest way to get your car back on the road at this point is buy a reman converter and install it along with the trans from your parts car.

Would have been nice to have examined the front pump while you had it out. I have seen one with both driving tangs sheared off.

I did turn the TC and heard fluid. I have to get a better way to remove the transmission. There was very little I could do while balancing it on a block of wood on top of a floor jack. I guess I am really going to be doing this, so I may as well get a few things to make the work easier.
I was having dinner after wards and my son says, "Dad, you have mechanic fingers". I smashed another one between the transmission and something. Now I have two fingernails on the verge of displacement.

Kingdoc1, what do you mean by contamination?
I have found no signs of metal or anything anywhere. I drained the old TC and found the brand new ATF that I put in the other day. I even matched color to brand new fluid and it was exactly the same in a glass. I drained the transmission...again, and still the same color as the brand new fluid. I have never found anything in the ATF, ever, at all.

Agree
 

Seating the torque converter is critical.

The converter must be rotated 7-14 revolutions, and gently pushed in, feeling the 3 or 4 seat steps.

If the torque converter was not seated fully/correctly before installing the first time, the pump would be wrecked during transmission mounting.

a better way to remove the transmission
 

Hmm 7-14 revolutions? That's good to know, but why so many ( I will be putting one in in a few weeks)?

Is it good to avoid the number 13?:D

Answer
 

Because you are seating several drives = clunk drive #1, Clunk drive #2, etc.
Each seating allows the torque converter to set deeper in the bell housing.

Just what I need, another reason to stop at HFT. I stop there every day on my way home from work (twice/week).

I probably will not be able to give an update for a week. I will have to get the transmission out of the other car and do a switch. I will let you all know how it goes from there.

Thank you for all the advice and info on getting these things "matched up".

If you look into the transmission past the input shaft seal, you will see the front pump gear. You should see two slots in the gear 180 degrees apart, these are where the little raised tangs on the torque converter hub must engage to drive the front pump. When you look at the end of the transmission input shaft, you will notice that there are a couple of different sized splined areas--these fit into female splines in the torque converter. If you look into the converter you will see them. As whhunter stated, you must spin the converter as you install it and you will notice that it will seat further into the bell housing as each splined shaft engages and as the drive hub tangs engage the slots in the front pump gear. When you install the converter bolts, you will notice that you will actually move the torque converter forward, toward the engine crankshaft when it is installed properly. You will also notice with the engine and trans bolted together and the torque converter bolts not installed, the converter should spin easily. If you can't turn it easily, something is very wrong. A simple way to tell if you have installed the converter properly would be to place a straightedge across the front surface of the bellhousing and push the converter all the way back and measure the distance from the center of the converter where it seats in the crankshaft to the straightedge. Of course, you would measure this before you remove the original converter, and then when you reinstall the converter you would know it is seated all the way. Once you have it in correctly, you must make sure it does not slide out while you are manuevering the trans into place under the car, not an easy task if you are trying to install a trans with a block of wood and a floor jack. I have used a large c-clamp in the past, clamping it to the lower part of the bellhousing in such a way that it is against the converter and will not allow it to slide forward. By contamination I mean that if the converter is not properly installed, then parts that should be rotating coupled together may be rubbing on each other, and this can cause minute metal shavings to be generated that will circulate with the fluid. Since the metal is generated in the area of trans that is downstream of the filter, it can travel into the inner workings of the trans unfiltered, when it can damage other components. The pump fills the torque converter with fluid, so the converter is one of the first places the trash is going, and it is about impossible to clean it all out. If you then put the contaminated converter into a good trans, it may work for a short time, but it will ultimately destroy your good trans. Don't take that chance, unless you are willing to gamble the price of another trans and converter.

I wish I didn't have to go to work tomorrow!!!
I want to go out right now and get started with this info!!!!!!!!!!!!!
Yahoooooo, I can't wait!!!

Thank you!!

Please break up your sentences
 

If you look into the transmission past the input shaft seal, you will see the front pump gear.
You should see two slots in the gear 180 degrees apart, these are where the little raised tangs on the torque converter hub must engage to drive the front pump.
When you look at the end of the transmission input shaft, you will notice that there are a couple of different sized splined areas--these fit into female splines in the torque converter.
If you look into the converter you will see them.
As whunter stated, you must spin the converter as you install it and you will notice that it will seat further into the bell housing as each splined shaft engages and as the drive hub tangs engage the slots in the front pump gear.
When you install the converter bolts, you will notice that you will actually move the torque converter forward, toward the engine crankshaft when it is installed properly. You will also notice with the engine and trans bolted together and the torque converter bolts not installed, the converter should spin easily.
If you can't turn it easily, something is very wrong.
A simple way to tell if you have installed the converter properly would be to place a straightedge across the front surface of the bell housing and push the converter all the way back and measure the distance from the center of the converter where it seats in the crankshaft to the straightedge.
Of course, you would measure this before you remove the original converter, and then when you reinstall the converter you would know it is seated all the way.
Once you have it in correctly, you must make sure it does not slide out while you are maneuvering the trans into place under the car, not an easy task if you are trying to install a trans with a block of wood and a floor jack.
I have used a large c-clamp in the past, clamping it to the lower part of the bell housing in such a way that it is against the converter and will not allow it to slide forward.
By contamination I mean that if the converter is not properly installed, then parts that should be rotating coupled together may be rubbing on each other, and this can cause minute metal shavings to be generated that will circulate with the fluid.
Since the metal is generated in the area of trans that is downstream of the filter, it can travel into the inner workings of the trans unfiltered, when it can damage other components.
The pump fills the torque converter with fluid, so the converter is one of the first places the trash is going, and it is about impossible to clean it all out.
If you then put the contaminated converter into a good trans, it may work for a short time, but it will ultimately destroy your good trans.
Don't take that chance, unless you are willing to gamble the price of another trans and converter.

Whunter: thanks for pointing that out-It didn't occur to me that it was hard to read!

Okay, here's the update!!! Apparently I did not seat the TC all the way during the first installation. This resulted in shearing off the tabs on the pump.

I removed the transmission from my parts car and installed it. She moves like a rocket!!!!

Upon returning home I noticed transmission fluid leaking from between the housing of the transmission and the engine. This usually indicates a seal problem. I put a new seal in before I installed the transmission. And I had driven the parts car home (45 miles) and never had any leaks.

Any other places this thing could be leaking from?

I can now change out a transmission in 4 hours. I bought a transmission lift!!!!

I did some checking and on the leak issue from the front of the transmission. As I stated, I had replaced the front seal but now the dealer said I should have replace some sort of 'O' ring?
He said to remove the 9 bolts and there will be an 'O' ring there. Well, I removed the 9 bolts from my other transmission and darn near pulled out the entire insides of the transmission. Everything there except an 'O' ring.

Does anybody know what this dealer is talking about?

Probably the front pump seal. This is a huge o-ring about the size of a large grapefruit that seals the front pump (steel) to the alloy B3 mechanism (not really sure that is what it is called). When you did this on the "other transmission (removed the guts) you had the front pump assembled to the B3 assembly. You need to go that far, then compress the series of springs on the back (inside) to remove the retaining ring. Then remove the B3 piston and BEHIND there you will see some bolts that hold the front pump to the B3 assembly. When you get THOSE off and push the front pump off you will get to that O-ring. That's why I am rebuilding one of these for my wife's car- It has been leaking like yours for years....

Rick