I am having some issues with the lock up of my TH200 4R. Even with only little load the lock up clutch starts slipping. I have read, that there are two little filters called "Governor screen assemply" somewhere in the transmission. One for the lockup solenoid, one for the governor. I can not find any hint in the repair manual I have. Has anybody here seen those filters in the 200 4R? Maybe a clogged filter is to blame, limiting pressure to the LUC.
the governor screen assembly is in the backside of the front pump, near one of the big notches. right by the converter clutch valve.
So the oilpump must come out, to get access to these filters? That would be a bummer. I have read (attention: internet wisdom ), that there is another filter inside the pump, which looks like this: Can you confirm? No, not yet. Will do that before dropping the pan. The solenoid has probably two stages, open and closed, which is controlled by 0V or 12V. Nothing in between, right? Whats the lowest voltage for the solenoid to operate?
Its a 12 volt solenoid. I would make sure there is good clean power and ground there before tearing the trans out.
Here is a link for you. Page 93 of 96 (Figure 174). The governor screen is item number 233 in the illustration. https://shop.ukrtrans.biz/wp-content/uploads/catalogs/TH2004R.pdf
The other thing to consider is to disable the lock up converter all together. If your converter is stock or near stock then you really don't need it. The loss of MPG will barely be noticed and there is no ill effect to the trans. Its certainly your choice but I'd have a hell of a time convincing myself to pull the trans for it.
I believe this screen belongs to the TH700-R4, 4L60, 4L-60E family. I don't recall it in the TH200-4R, but I'm getting old.
Thank you guys. I have driven the Buick yesterday and today with perfect LUC function. I wonder if what I experienced during the long highway trip is a "hot condition" situation. Even though I would think that driving in 4th gear with LUC closed should not create too much heat in the transmission. In particular given the fact, that I have a deep oil pan plus an oil cooler installed. Somewhat clueless
Why do you think that the TCC is slipping? It's either on or off. If it feels like it's bucking, make sure that you don't have a misfire. It's amazing how many transmission problems that come into the shop end up being engine issues.
Update: I contacted Lonnie from Xtreme, asking for advise. He replied, that the LUC is not designed for high engine torque, just for torque levels at cruise. I will install a vacuum switch, so that the LUC will open during accelaration. As to the little filter: it is not installed in my transmission. Lonnie said the usually leave them out when rebuilding a transmission. I know, that it is on or off, not a controlled slipp, like in todays cars. No misfiring or bucking in my case. Just slipping.
