722.3 is the worst transmission ever put in a modern car. - PeachParts Mercedes-Benz Forum

rwd4evr · #1 02-26-2021, 08:16 PM

I've owned cars of many many different varieties and I've owned a whole lot of Mercedes with 722.3 automatics and I firmly believe that they are the worst pieces of s*** ever put behind an engine with a torque converter. Not a single one of my cars has ever behave the same on two different days or sometimes even 10 minutes apart. Won't drop into first gear won't shift into 4th gear until 75 miles an hour. just ridiculous. I don't have the time to just swap all of them with manual transmissions. So has anyone come up with a way to do a full manual valve body that will downshift when you tell it to and not when it gets around to it, and you need a way to put it in first gear without some computerized nonsense in a hydraulic transmission. So glad that garbage will be permanently out of my 300sd this week.

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whipplem104 · #2 02-27-2021, 12:09 PM

Modern Car? It was basically designed in about 1975. I would say that they are incredibly reliable. They are now in all reality atleast 25 years old if you have the last one ever made. But by your list of cars closer to 35 years old.
They are setup for very different driving characteristics than most U.S. drivers like. European shift curves are very different. Even in todays current production cars. If you are having problems with reliability the valve body is the only thing that can be inconsistent for shift points. Governors fail but normally do not stick. Also the detent switch on the floor is highly problematic and can keep you out of passing gear and also always have you in passing gear. A fresh rebuild and a new detent switch and properly adjusted bowden cable and they are rock solid for about 100-150k or more.

Roncallo · #3 02-28-2021, 06:04 PM

A 722.6 might be a good option for you. Since they were used in many Chrysler vehicles there is a lot of stuff to make them do what you want to do.

ccrelan · #4 02-28-2021, 08:43 PM

Did you pay over $500 for any of these cars?

rwd4evr · #5 03-06-2021, 04:25 AM

Quote:

Originally Posted by whipplem104

Modern Car? It was basically designed in about 1975. I would say that they are incredibly reliable. They are now in all reality atleast 25 years old if you have the last one ever made. But by your list of cars closer to 35 years old.
They are setup for very different driving characteristics than most U.S. drivers like. European shift curves are very different. Even in todays current production cars. If you are having problems with reliability the valve body is the only thing that can be inconsistent for shift points. Governors fail but normally do not stick. Also the detent switch on the floor is highly problematic and can keep you out of passing gear and also always have you in passing gear. A fresh rebuild and a new detent switch and properly adjusted bowden cable and they are rock solid for about 100-150k or more.

Yes modern car. Anything after about 1965isa modern car with where the automatic trand is relatively the same design. I have had tons of gm cars and even ford's with stupid amount of miles on them that don't misbehave ever ntil they are completely worn out, and you can feel them start to slip and know when it's time for a rebuild. 722.3 tans missions could work perfectly every other day except on Tuesday the 7th then for 6 days completely bonkers for 4 days with absolutely no change in adjustment or condition of a single part in them. They decide not to go into reverse some times and work completely perfectly all other times sometimes for years for some people. I don't want to hear about european shift curves or any nonsense like that. If it behaves one way one day it should behave the same the next day. If it's broken it wouldnt work perfectly half the time. They have issues. Sure they may last 150,000 miles but half of them are annoyingly in the wrong gear. And to top it off no detent for every gear. That is the stupidest thing I ever heard of. Well besides maybe second gear starts. DUMB. I have a saying about mercedes cars. Massive amounts of wonderful engineering and a little bit of stupid. you can always find a few things designed on " Bring your special nephew to work engineering day" .
For instance ,w123 and w126 driver knee panel. Giant
plastic philipss headed square screw that doesn't really have threads. What the hell is that? The other side has glorified drywall screws into the carpet. 72.3 shifter was definitely one of those days.

rwd4evr · #6 03-06-2021, 04:31 AM

Quote:

Originally Posted by Roncallo

A 722.6 might be a good option for you. Since they were used in many Chrysler vehicles there is a lot of stuff to make them do what you want to do.

Yes. The of gear controller is pretty good and they take gobs of power. I have heard the controller take a lot of time to get programmed for all situations though and they don't bolt up to early six's or diesel om61x. The best solution is always a manual. I'd rather live with one in traffic occasionally than not have control on a nice drive. Man, sampson with a six speed, oh yes!!

rwd4evr · #7 03-06-2021, 04:39 AM

Quote:

Originally Posted by ccrelan

Did you pay over $500 for any of these cars?

Hmmmmm? Maybe a few. Buti think the more expensive ones were some of the worst misbehaving. What I paid is irrelevant anyway. Iperical data tells me that they are unreliable in operation .only one has left me stranded but at least 10 have pissed me off randomly not doing what they are supposed to out of the blue then are fine the rest of the time. Hunting around for gears for no reason. Upshifting early, one minute late the next. It's a design flaw internally. Something is not right.

ccrelan · #8 03-07-2021, 03:41 PM

Quote:

Originally Posted by rwd4evr

Hmmmmm? Maybe a few. Buti think the more expensive ones were some of the worst misbehaving. What I paid is irrelevant anyway. Iperical data tells me that they are unreliable in operation .only one has left me stranded but at least 10 have pissed me off randomly not doing what they are supposed to out of the blue then are fine the rest of the time. Hunting around for gears for no reason. Upshifting early, one minute late the next. It's a design flaw internally. Something is not right.

So you have extensive experience buying parts cars who's trans do not operate very well.

t walgamuth · #9 03-07-2021, 03:50 PM

The transmissions are known to last the life of the car if given decent care. What you want to do with them is not decent care.

They are not built in the quantities of the domestic companies so after market devices to make them work better are not existent either.

Tony H · #10 03-07-2021, 03:58 PM

I would rank the transmission in our Honda Odyssey as a close 2nd. It is designed to fail just after the warranty expires. Same with the rebuilt that replaced it. If the rest of the car wasn't so good it would have been gone years ago.

rwd4evr · #11 03-07-2021, 05:00 PM

Quote:

Originally Posted by ccrelan

So you have extensive experience buying parts cars who's trans do not operate very well.

No i.have extensive experience buying mercedes that have 722.3 transmissions that operate perfectly when they feel like it and not when they don't. I daily drive multiple different cars with them so it's not like I bought one cheap car and that's my basis for saying this.

rwd4evr · #12 03-07-2021, 05:04 PM

Quote:

Originally Posted by Tony H

I would rank the transmission in our Honda Odyssey as a close 2nd. It is designed to fail just after the warranty expires. Same with the rebuilt that replaced it. If the rest of the car wasn't so good it would have been gone years ago.

I've seen this issue with hondas too. Engineered failure point. How else would they sell new cars? Timing belts and autos that quit. A guy pulled up. Parked put gas in his accord then tried to leave. Wouldn't go into any gear all of the sudden. Never had a single issue. Tranny fluid smelled and looked good. I checked the shifter cable operation. Something internal just quietly let go.

rwd4evr · #13 03-07-2021, 06:10 PM

Quote:

Originally Posted by t walgamuth

The transmissions are known to last the life of the car if given decent care. What you want to do with them is not decent care.

They are not built in the quantities of the domestic companies so after market devices to make them work better are not existent either.

That makes zero sense. They make less so they shouldn't work properly is your answer? What do you consider "decent care"? Keeping them full? Occasionally changing the filter? Is there a checklist for "decent care of automatic transmissions" that I'm unaware of? My bowden cables are properly adjusted. If decent care means not driving a car hard then the trans isn't up to it's task. What do.ypu mean"what you want to do.with them" anyway? Deliver pizza and drive to work? I've never smoked one towing but I wouldn't complain if I did. Not shifting correctly or even consistently has zero to do with how I drive or what I'm doing with the car. . In a car that cost equivalent of over 100,000 dollars today that is absurd. 120 hp in a 3800 lb car it's getting it's neck wrung out just to not get smoked by a trash truck. Don't be silly tj. You are a manual swap guy anyway.

rwd4evr · #14 03-07-2021, 06:16 PM

Quote:

Originally Posted by t walgamuth

They are not built in the quantities of the domestic companies so after market devices to make them work better are not existent either.

Of gear 722.6 controller works great from what I hear. Just a lot of tuning to get it fully set up.

whipplem104 · #15 03-08-2021, 01:11 AM

I just think that your complaint is strange to me. That after over 20 years of working on them professionally. And driving a few thousand cars. Lets say around 2500-5000. I really could not say in all those years. And I have owned at least a dozen cars over the years with the transmission. That not once have I found that they were inconsistent or that anyone ever complained about them being inconsistent. I have had a few sporadic complaints that were a direct result of a bad part that was fairly identifiable. By the very nature of the hydraulics they cannot be inconsistent if they are in good shape. A bad seal or worn bore or a something that is leaking more when cold vs hot or vice versa could give you different results but again this should be fairly identifiable. And again not something that any customer or car that I have ever had or driven has had a problem like this. Not to say that it could not happen as they are getting older by the day and what was never a problem 10 years ago can be a big problem today.
And I am sorry but no GM transmission last for 30 years without being rebuilt a few dozen times.

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