Automatic Transmission problem after swap

[jacobkk]

My car is a 96 Camry LE Automatic, A140E transmission

I read through tons of threads but couldn't find one with the same problem. Long story short I swapped my slipping transmission with one from a junk yard which supposedly has 112k miles on it. The first time the gear in the oil pump broke (my fault I think) so I took it apart again and replaced the oil pump with the one from the old transmission. Now the transmission functions perfectly except for this issue of after it's been sitting for a while, say overnight, when I start the car and shift into reverse or drive it won't move, the engine revs like it should but I get no drive at all for 30 seconds or so, then it suddenly shift into gear like normal, no hesitating or odd noises, it just drops into gear like I had shifted it normally, then after that it works perfectly, shifts nice and crisp and everything's dandy, until I let it sit for an extended period again and it might or might not repeat that scenario. The fluid level is correct, and I have driven it a few hundred miles at least since doing the swap and everything's fine once it goes into gear, which never takes more than a minute or so to happen.

I would think if there was low oil pressure it would be acting up in other ways, or perhaps I messed up a seal or something and fluid is draining where it shouldn't when it sits for a while.

Another issue which probably isn't related, but I might as well mention it, is now after doing the swap (only after, it was fine before) it idles very low, like 300rpm low, in reverse once the transmission gets hot. It actually idles normally for about a second then drops suddenly. It also does this in drive sometimes but if I shift from D to N and back to D it idles normally. Again this is a new development with the new transmission it was fine with the old one. The old transmission was slipping badly and had no reverse after a few miles of driving, but always went into drive just fine

Ok that was too long but any help or ideas would be greatly appreciated.

[JohnGD]

Sounds like a torque converter leak down problem. A worn seal is a possible problem.

When you shut down the engine check the ATF level as time passes. See if the level continues to creep up.

[jacobkk]

What seal or seals would cause this? Is it just the torque converter seal on the front of the oil pump? Like this one... http://www.carpartswholesale.com/v5/...Listing+Page:1
Or are there others inside that may need replacing?

I will check the fluid level over time after shutting the engine off, but I was thinking if the torque converter had drained down it would not suddenly engage but would sort of slip into gear in an abnormal way as the pump filled it up again, but I'm just guessing, never had this problem before.