99 E300 transmission shot - Suggestions needed please

[DieselDood]

Hi Everyone,
It has been a while since I posted/visited here. Have been driving 99 E300 with 295K miles (bought a few months ago) and the other day trans made noise coming from near the glove box and then no gears - it quit before I got onto a highway and so had it towed home. Other than that it runs really nice and has a greasecar kit which I haven't used much.

So I am reading that it has the 722.608 trans, the famous "sealed for life" one. I also found youtube video series on this trans that recomend changing the electrical control panel and the valve body that it sits on. Not being very mechanically skilled as most of you, I am not sure what to do. I would hate to lose the car and I want to have it fixed but not really get robbed. Just had a new radiator installed as stuff on the road hit the fan literally and broke the fan blade which hit the radiator and punched a hole. Then the battery died and it was something to install it as I had to find it first. Anyways wondering if any folks in the DC area who can help. Would like to hear any suggestions and how I can go about it. Thanks in advance

[97 SL320]

Losing all motion at once isn't common. Not every failure I've listed below has a noise associated with it but it is good practice to check.

If the electrical plug on the trans was removed, you would still have 2nd and reverse so don't look for a electrical problem yet.

Start with, On a level surface,with the car in park and the parking brake released, try to push the car back and forth. It should move a few inches in each direction then stop.

If car moves farther, look at drive axles, rear differential and input flange, drive shaft rubber discs, transmission output flange. If the nut holding the trans or diff flange comes slightly loose, the splines will wear out and strip. This has happened a few times on this list across a few different models of trans.

Next look for signs of fluid leakage, use a dipstick tool to check fluid. ( at this point you are looking for a drastic 2 Qt down situation not a 1/2 Qt.

Jack the front of the car up and support with stands or use drive on ramps. You need to look at the flywheel / flex plate to torque converter bolts, there are 3 sets of 2 bolts ( 6 total ) , make sure these didn't fall out.

Look through the vent holes at the bottom of the bell housing, identify the torque converter, have someone crank the engine and look to see that it turns. If no rotation, the flex plate has cracked. ( make sure you are not just looking at the flex plate / flywheel )

If the torque converter turns, remove both trans cooler lines and put a pan under them. Crank the engine, fluid should come from one of them. ( you need to have the pan under the trans side of the lines, be ready for a fluid spray. Make sure you are on the transmission lines and not an engine oil cooler. ) The fluid on these trans normally gets dark, only be concerned if it smells burnt.

If no fluid comes out and there is fluid in the trans, the torque converter pump drive slots / trans pump drive tangs have sheared or the pressure regulator spring in the valve body has failed.

If you get a fluid stream, the trans has to come out for a look.

The 722.6 is used on many Dodges during MB's ownership of Chrysler ( and a Jaguar or two ) so knowledge can be found at a decent domestic transmission shop. There is no need to go to a MB specific shop.

Please report your findings so it helps others in the future.

[DieselDood]

SL320....thank you for the quick response and the excellent directions to follow. I am probably capable of only doing the first one which is pushing the car back and forth. I don't have the special dip stick and I suspect I have lost some trans fluid as I see a mark on my garage floor. It is not too bad as it doesn't seem to be much. On the other directions I think I will need to find someone to help me.

[DieselDood]

Strange thing I forgot to mention is that if I leave the car parked for couple of days outside as I did, I was able to start it and drive into my garage just now with now problems. This has happened couple of times where I had left it for couple of days and started it up and drove around for couple of mins and the car behaved like - what transmission problem!. But after a few mins it was back to its old self again.

I checked the rocking back and forth with car parked on my garage floor and the car was normal. ie it did not go forward too much and back too much. I am dreading the next steps outlined by SL320 but I will see if I can crawl underneath.

[pimpernell]

Originally Posted by DieselDood

Strange thing I forgot to mention is that if I leave the car parked for couple of days outside as I did, I was able to start it and drive into my garage just now with now problems. This has happened couple of times where I had left it for couple of days and started it up and drove around for couple of mins and the car behaved like - what transmission problem!. But after a few mins it was back to its old self again.

I checked the rocking back and forth with car parked on my garage floor and the car was normal. ie it did not go forward too much and back too much. I am dreading the next steps outlined by SL320 but I will see if I can crawl underneath.

I would definitely find a way to check the transmission fluid level. By the car sitting, there is no way that a mechanical issue will right itself even for a few minutes. If you are low on fluid, what may be happening is that by sitting for a few days, what fluid there is collects and then for the first few minutes, the car drives o.k. but with the lack of proper fluid, it starts to fail.

[DieselDood]

Thanks, I will order the dipstick I saw on amazon/ebay. Definitely I should check the level.

[jay_bob]

Originally Posted by DieselDood

Strange thing I forgot to mention is that if I leave the car parked for couple of days outside as I did, I was able to start it and drive into my garage just now with now problems. This has happened couple of times where I had left it for couple of days and started it up and drove around for couple of mins and the car behaved like - what transmission problem!. But after a few mins it was back to its old self again.

I checked the rocking back and forth with car parked on my garage floor and the car was normal. ie it did not go forward too much and back too much. I am dreading the next steps outlined by SL320 but I will see if I can crawl underneath.

If the fluid is ok then I would next look at the conductor plate. I can definitely see a thermally induced failure in the connections or sensors there being a plausible cause. Something that would fail at temperature but when it cools down it returns.

Are you getting a Check Engine light and message? If so plug an OBDII reader in and see what the code is. If you have something in the P07xx series that is the transmission. The codes transmitted by OBDII are a very limited subset of what is available over the proprietary diagnostic system, so it may be good to get an indie to pull the data for you if you are getting a P07xx code.

[DieselDood]

My fancy harborfreight ODBII didn't want to give me any codes. There is no check engine light on. I just ordered another scanner, this time an el cheapo one - maxiscan ms300. Just ordered the dipstick also and I am hoping what pimpernell noted comes true and I can fill her up with the lost fluid and then I can take it to a mechanic to put it up on the lift and check all the things that SL320 noted.

Hopefully somewhere down the line I can check the electrical contact plate as you suggested jay_bob. Thanks.

[dude99]

Strange thing I forgot to mention is that if I leave the car parked for couple of days outside as I did, I was able to start it and drive into my garage just now with now problems. This has happened couple of times where I had left it for couple of days and started it up and drove around for couple of mins and the car behaved like - what transmission problem!. But after a few mins it was back to its old self again.

This is a bad sign. Your transmission has failed mechanically. Something metal has failed and filled the transmission pan with debris that is clogging the filter. When you let the car sit the debris falls off the filter to the bottom of the pan so the transmission can suck up fluid, build pressure and work. However shortly, the debris is sucked up and plugs the filter again causing pressure loss and a no drive situation.

The same thing happened to my father in laws w203. Transmission blew, turned the car off bad the restarted, the car would work for a few minutes then fail again. If you pull the pan off I bet you'll find it's full of debris.

[DieselDood]

Originally Posted by dude99

This is a bad sign. Your transmission has failed mechanically. Something metal has failed and filled the transmission pan with debris that is clogging the filter. When you let the car sit the debris falls off the filter to the bottom of the pan so the transmission can suck up fluid, build pressure and work. However shortly, the debris is sucked up and plugs the filter again causing pressure loss and a no drive situation.

The same thing happened to my father in laws w203. Transmission blew, turned the car off bad the restarted, the car would work for a few minutes then fail again. If you pull the pan off I bet you'll find it's full of debris.

So you are saying even if the pan is cleaned up, it won't work as all the metal inside will keep clogging the filter up?? So the trans has to be pulled out rebuilt or replaced??

[TMAllison]

Originally Posted by DieselDood

My fancy harborfreight ODBII didn't want to give me any codes. There is no check engine light on. I just ordered another scanner, this time an el cheapo one - maxiscan ms300. Just ordered the dipstick also and I am hoping what pimpernell noted comes true and I can fill her up with the lost fluid and then I can take it to a mechanic to put it up on the lift and check all the things that SL320 noted.

Hopefully somewhere down the line I can check the electrical contact plate as you suggested jay_bob. Thanks.

In my opinion, it needs to be checked with a high end scanner to help determine what's wrong and then decide if its worth fixing or a parts car. MB's scanner or Xentry or similar capable of pulling MB trans codes AND actual values (how the trans has been internally adj itself over time). OBDII scanner won't read those proprietary systems and on the off chance it does spit out a code it will be something Generic like P0700 or P0715 which tells you nothing.

Even if you were to guess right and fix it, you wouldn't know, it would still stay in limp mode (R & 2nd gear only) until it is reset/cleared with a compatible scanner.

[DieselDood]

Originally Posted by TMAllison

In my opinion, it needs to be checked with a high end scanner to help determine what's wrong and then decide if its worth fixing or a parts car. MB's scanner or Xentry or similar capable of pulling MB trans codes AND actual values (how the trans has been internally adj itself over time). OBDII scanner won't read those proprietary systems and on the off chance it does spit out a code it will be something Generic like P0700 or P0715 which tells you nothing.

Even if you were to guess right and fix it, you wouldn't know, it would still stay in limp mode (R & 2nd gear only) until it is reset/cleared with a compatible scanner.

Hoping I can drive it to the mechanics to have that done if she will let me. Waiting to get the dipstick that was ordered and to top the fluid off. I just want to get a baseline of how much fluid I am down. But dude99 made a good point about the metal in the pan. So I am not sure yet.

[dude99]

So you are saying even if the pan is cleaned up, it won't work as all the metal inside will keep clogging the filter up?? So the trans has to be pulled out rebuilt or replaced??

The metal clogging the filter isn't the issue so to speak, its the result of the issue. Odds are a gear or clutch pack ate itself so cleaning the pan out wouldn't fix it. I would imagine that the trans will need a full rebuild, but this is just a guess. I would not drive it ANYWHERE!!!!. You don't want to do more damage, the more parts you break the more expensive the rebuild gets, especially if you start breaking things that aren't included in the standard rebuild kit. I would flatbed it to a transmission shop.

[DieselDood]

Originally Posted by dude99

The metal clogging the filter isn't the issue so to speak, its the result of the issue. Odds are a gear or clutch pack ate itself so cleaning the pan out wouldn't fix it. I would imagine that the trans will need a full rebuild, but this is just a guess. I would not drive it ANYWHERE!!!!. You don't want to do more damage, the more parts you break the more expensive the rebuild gets, especially if you start breaking things that aren't included in the standard rebuild kit. I would flatbed it to a transmission shop.

Thanks for the advice.

[lespigpen]

I second the conductor plate. The build up of fine contaiiments cause the solenoids on the plate to malfunction this disabling the vehicle.
When left to sit for a period of time, the contaiiments fall down then enabling the trams to work. ....for awhile that is.
Mileage indicates you would need this conductor plate. Even as preventative maintenance. I think you may have a drain plug in your torque converter as well as the pan.
So, a total replacement maybe avoided .
Let us know.. Good luck👌