722.3 transmission problem
 

OK all you tranny experts, here's the question. Reverse delay, sometimes long 5-8 seconds, sometimes normal 1 sec or less. Does not seem to be related to temp, ie, cold versus warm. Line pressure at idle is 82-85 psi in drive, 140-150 psi in drive at converter stall. If this were a seal in front drum or input shaft, I wouldn't expect it to vary as it does. My best guess is something hanging in the valve body. Haven't pulled base yet. Fluid is clean. Forward gears are fine. It's that darn MBZ reverse virus again :confused: :confused:

Ok man I will give it a try. What year is the car, how many miles, whats the service history on tranny?

89 300E (mine) 199,018 miles. Replaced tranny at 178,000 with rebuilt. Working fine until last week when this started. Fluid and filter replaced once (at 185,000) since install. Control pressure cable is adjusted to spec. Vac is good. Pressures are good..

Wow that didnt last long. My first impression is that there is a seal leaking. The most suspect would be the umbrella seals on the B3 piston. But there are several other components in the reverse circuit. I have the theory manual on that tranny. I will post a schematic of the oil flow for the reverse mode. You can trace it out and see which components in the valve body are involved. Thats all I can think of other than talking to my resident expert on the subject. I have the files at my office so it will be some time monday. Post your email address to I can send them directly to you.

A little more in the way of amplification. Even with the delay, once the tranny locks up in reverse, it does not slip, shudder or misbehave in any way. If you increase the rpm's to about 1200 it will decrease the delay (raising line pressure.), but when you let it drop back to idle, it maintains engagement. I am not an expert on MBZ trannys by any stretch of the imagination, but my experience with GM, Ford and Chrysler tells me valve body is the culprit. A blown seal would always leak, but who knows..

If the trans was recently rebuilt, I would suspect something got damaged on assembly. Most likely a seal. Another possibility is that too much end play was built into the clutch pack. The reverse clutch is very big in diameter and if there is a lot of play it will take a lot of fluid to fill.

There is a kit made for changing shift characteristics. It makes no specific VB repair for delayed rev but does show a VB plate hole to enlarge for delayed engagement in particular. Email me if you wish to go that route.

steve_ci@bellsouth.net

OK, go figure...This AM headed to work, started her up, selected reverse, waited for delay :( , what the hey, no delay :D :D . Totally normal behavior. That's gotta be the valve body. Plan- watch for a few days:confused: :confused:

722.3 Reverse delay concerns
 

There may be many reasons for your reverse delay concern. However, if this problem has been evident both prior to and/or after overhaul, then you may solve this by making some modifications to your control valve assembly. This repair should not be attempted by someone that is unfamiliar with this type of work.
This is a fairly common complaint that we at ATSG deal with on a regular basis. If you can provide me with a fax # then I will send some information from our 2001 seminar book dealing specifically with reverse concerns with the 722.3,4,and 5 units.

Gerald, give me an email address and I will send fax #

Thanks

ATSG ? way cool.

There are lots and lots of people here on this list that would love a course on transmission work. From the simple like "do this to correctly adjust the linkages", to the take it apart and put it back together again so it actually works, to the "if you do this you can hit warp 2".

Anything your organization has to educate the masses (or even just a select few of us ready for the challenge) would be greatly appreciated.

Your web site of transmission overhaul procedures will soon be very helpful.

-CTH

Gerald - I would be most interested in asking some pertinent questions concerning the operation of an automatic tranny in a 1985 300D. Please send me an email address so I can send you a fax #.
thanks

722.3 reverse concerns
 

Jeff, Jim .....You can E Mail me at Gerald@atsgmiami.com and then I'll forward that info you require via fax.
Regards; Gerald.

Reverse Pulsing
 

I noticed the discussion on the delay in engaging reverse and then back to "D" drive. I also notice that I have to pause somewhat before pressing the throttle since the transmission doesn't go into gear right away . I've acclimated myself to this idiosyncracy but annoying when someone is waiting for your parking space and they think you're taking your sweet old time and being a jerk. However, I still have a question on the behavior of reverse on my car:

In reverse, backing into a slight incline, motor/car has not been running for about an hour (lunch) but engine/trans is warm, the car will move in a pulsing motion as if there isn't steady power. Not a normal power delivery, it seems. Now, this is only after I've taken my foot off the throttle and the car's momentum is still taking it backward so the "power" delivery I'm talking is hopefully not misleading. I back it out conservatively and not doing anything close to a tire burning peel out, either. I'm curious as to the reason behind this and if it means some problems are impending.

If the B3 friction disks are worn or in some cases have come apart, the K1 clutch pack will rub against the B3 piston causing a jerky pulsing motion in reverse. That coupled with the fact that it takes a long time to engage tells me that you probably have some serious problems.

I had similar problems with my 91 420sel. When I opened the filter there were large pieces of the B3 friction disks in the filter. It was interesting that there was no indication that these large particles were there until I cut open the filter and examined it closely. The filter did a good job of catching these particles. There was nothing in the pan what so ever, it looked clean. Needless to say I was horrified when I got the filter open.

However your car is much newer than mine and I cant say if my experiences apply in your case.