I am working on a guys '81 300SD. The trans flares on the 2-3 shift and 3-4 shift only when the trans is cold.
Here is what I did:
1) Serviced transmission with new filter, drained torque converter.
2) Installed the K-1 spring kit
3) checked vacuum at idle and WOT, within perameters.

When I pulled his origional valve and spring setup in the K-1 port, His trans had STEEL plunger parts in it instead of plastic. I used the plastic parts from the kit and kept his STEEL parts.
Can the two rings on the green plastic piston in the K-1 port need to be replaced? I saw NO chunks nor was the fluid burnt when I serviced the trans.

ONE THING that He did before I got it to work on the car was he drove 60 miles with the vacuum control rod disconnected from the throttle linkage to the bleed off valve on top of the pump.
In other words, The trans was driven with full vacuum to the modulator thus making the trans think it was at idle to low throttle demand.
ANY ADVICE IS APPRECIATED!

__________________
My Truck.. 2007 DODGE, 5.9 Cummins, 6spd stick, 4X4. My car..1977 240D, OTHER WHEELS...1955 VW Oval window bug, European Delivery (Holland) with a 1700cc, 2 barrel, Porsche drum brakes. 1939 WILLYS Pick-up. 1967 Triumph 200cc Tiger Cub. 1976 Honda 550F 4cyl Motor Cycle.

The above is what he did.

The above is what you did.

I don't see anything regarding reconnecting the control rod from the VCV to the throttle linkage. That's the first thing to do.

If you checked the vacuum at idle and at WOT........there is no possible way that they are within parameters without the control rod attached.

What happens when you disconnect the vacuum going to the modulator? All other things being equal, that should produce harsh shifts. If it doesn't I think it implies that the problem is in the modulator itself or the transmission (I think).

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Brian, Sorry I didn't say that I DID reconnect the control rod FIRST. The plastic clip had broken and I replaced it with a new one.

Kerry, I will try that also. Thanks

__________________
My Truck.. 2007 DODGE, 5.9 Cummins, 6spd stick, 4X4. My car..1977 240D, OTHER WHEELS...1955 VW Oval window bug, European Delivery (Holland) with a 1700cc, 2 barrel, Porsche drum brakes. 1939 WILLYS Pick-up. 1967 Triumph 200cc Tiger Cub. 1976 Honda 550F 4cyl Motor Cycle.