722.5 DELAYED REVERSE
 

1990 300SL-24 with a 722.5. Its had a delayed reverse since I got it 2 or so years ago. Put into reverse cold, engages right away and firm like how it should. When its hot, its delayed, give it a tickle of throttle and it engages with little to no slipping.

Transmission was rebuilt by a local transmission shop. Ill reserve my opinion of them for another time. I've been through the guts of this transmission myself twice now.

Before you all jump on me saying its the lip seals on the B3 piston and or reverse clutches......its not. They're new, and new for no reason a second time.

I too thought this was the issue the first go around again having extremely low expectations of the local trans shop but the seals were fine, pliable and installed correctly. I replaced them anyways. Same went for the clutches, all were healthy with little to no wear. Tolerances were not excessive when assembled, but again replaced them anyways while it was apart.




TODAY - I'm almost certain there's something up in the valve body. Removed the entire valve body to inspect for cleanliness, but only to find the valve body was surgically clean. Dumped out all the plastic balls re-assembled as per WIS and EPC. I didn't pull any of the accumulators out or springs. Put it back in the car and literally nothing has changed.


I am wondering and I paid close attention to this while it was apart, there's an old technical article about removing a ball and tapping the hole / installing a plug, applicable for the 722.3 and .5. I will attach this info below.

Curious on any commentary, and if anyone of you have performed this repair.

In close communications with the previous owner, she seems to think the delayed reverse has been a thing since the transmission rebuild but her memory isnt the greatest sadly.



TECH ARTICLE - https://www.transmissiondigest.com/september-2001-issue/

My car DOES NOT HAVE A REAR TRANS PUMP. Mine has cover 2022770003 on it. No rear trans pump.

Sounds as though the initial setting of the control pressure is a bit low.

I think if that were the case, it would affect drive as well, drive is a firm and positive engagement regardless of how hot / cold the car is.

?? Control pressure ??
Or pump output?

Sincerely appreciate the opinion Frank. Looking for someone who has done the repair as per the technical article listed above.

Thank you for your commentary.

And Beelzebub is anticipating frostbite.