97 C280 with 722.6 trans erratic after rebuild.
 

I just put together a 97 C280 722.6 trans. Pre rebuild it was operating properly but developed an interment buzz sound like a screw driver against spinning gear teeth and had the light throttle torsional vibration associated with a dragging torque converter clutch.

Changed frictions , seals , K2 bushing , torque converter, Sonnax shift sleeve upgrade ( o ring sleeve ), spring in Control Valve Pressure Regulating Valve.

Post rebuild the trans is erattic and won't make it through the shift adaptation without triggering this code: 55 151 P0730 GEAR RECOGNITION REPEATEDLY NEGATIVE ( Got this code on the initial road test , zeroed out adaptations, shifts were less harsh but still erattic , still got code. )

Sometimes it will start out in 2nd when coming to a stop after a good 1-2 shift. The 2-3 shift seems to be OK, maybe 3-4, sometimes toggles up / down between 4-5 or maybe 3-4. Trans still shifts bumpy, will eventually default to 2nd but no check engine light until I cycle the key.

I pulled the valve body thinking that I flipped the spring / small valve in a shift sleeve, these are OK. All check balls are in the proper places. I have another valve body that I can pop in but I'd rather find the problem with this one.

Will also open the trans computer for a look for oil.

Any ideas ? Thanks

Found the problem. . . car now shifts up in the air and should be OK on a road test.

This trans was built late 96 for the early 97 model year and didn't have all the up dates of a 99 era trans. As part of my updating, I added filters ( 140 270 04 98 ) to the Modulating and Shift Pressure solenoids.

The early solenoids on my car ( MB 140 277 00 98 / Bosch 0 260 130 015 ) had a 0.582" long stem that crushed the filter turning it into a semi effective plug.

Later solenoids from a 99 parts trans I have ( MB 140 277 03 98 / Bosch 0 260 130 015 , yes, same Bosch # as the older type ) have a 0.470" long stem to allow the filter to fit.

The fix was to trim the legs from one side of new filters and place the now flat side against the solenoid. This leaves enough room for fluid flow.

SL320,

Thank you for sharing this.

Filing off the dimples should work?

Martin

You are welcome.

I cut the legs off with a knife, sanding would make too much dirt. The surface does not need to be colmpetly flat since the filters have legs on both sides in their intended application.

When updating an old trans, it is critical that the legs are facing against the separator plate and the now flat side towards the solenoid. If the flat is against the sep late, there isn't anywhere for the fluid to go because there isn't a hole in the sep plate. If you pull one apart you will see what I'm talking about.

Excellent again, and thank you for the tips.

Martin