Your problem is a factory problem many TQF's suffered from, from the first to the last one built. The manual shift valve was designed in such a way fluid from the converter drained out to half level, starting the engine in P or N would not purge the converter of air until you put it in drive and it would feel like a rubber band winding up. There is a valve body kit that replaces the manual valve and fixes this, it's called a NOYOYO kit from Transgo. Gil Youngers original company, I have installed several of them along with shift kits and the problem is fixed for good. But then since you are running a reverse manual this may be a no go thing, I never worked with a reverse shift, only manual standard forward bodies. But the problem is still the same, the converter drains back. You need to contact Transgo and ask if the NOYOYO kit will function in a reverse pattern valve body first then follow their advice. Many methods have been tried to fix this including a check valve in the cooler lines and they all failed to some extent because they didn't address the real problem which was clearance in the bushings and seals in the converter charge system along with the fact the shift valve did not close off the port in the valve body that allowed fluid to drain down, which also raised fluid level in the pan and the next thing that leaked was the shift selector seal above the pan rail ! So many MOPAR trans, would leave a puddle of oil because of this design flaw. Add that to the fact that so many people would build these trans and install the little seal on the throttle pressure to the main shift shaft upside down because it was easier to install that way. The best way to install the little lip seal is to install it with the lip facing the pan and put a metal washer under the snap ring which will hold the inner shaft up and protect the rubber seal from the snap ring. I did read some about converting to a reverse pattern a long time ago and it was all done with drilling and plugging so the stock valve was likely used, if so than the NOYOYO kit should solve the problem, others here say it will. Asking Transgo will be the best advice. Working on these old trannys is not that complicated and with a set of instructions and a little patience and tools, some petroleum gel and it can be done by most anyone with mechanical hands and mind. I started my career with a TQF at 16 years old and learned how to do overdrives and electronic controls reading instructions and doing them.
