2006 mazda 5 transmission slipping after engine swap (calling all master mechanics)

[toridor]

I have just completed removing and replacing the engine on my 2006 5. Now the transmission is not working properly.
Symptoms:
- I have to rev it up a bit before it engages in reverse.
- while reversing, it will engage and disengage unless I get on the throttle fairly firmly...then it will fully engage
- it needs to revved up a bit less to go forward
- it will get around in 1 and 2nd in "manual" mode (its an auto)
- if I try to use 3rd or 4th, it really slips/revs

notes:
- ATF is full (MV grade/spec) - was all drained when I re-re'd the motor
- might be a bit too full, but I am a bit unsure to honest
- torque converter came off when the motor and tranny were split (I am fairly sure it was put back in place where it should be)
- tranny has 185k on it (it was working fine before the motor swap)

thoughts:
should I try dropping the ATF and replacing the filter to see what happens?

Thats what I know...I am really trying to avoid having to remove it again if I can help it. Any advice would be very much appreciated. I have been combing the net looking for info on this, but nothing so far.

 

[loosenut]

A couple of thoughts, none really positive. First if the trans is high mileage and the fluid had never been changed before now, then the friction material may have been drained with the old fluid. I've seen this happen on very high high mileage trans that have never had a fluid change. Second, if the torque converter wasn't reinstalled correctly it may not be engaging the fluid pump correctly, but if this was the case it would have been very hard to bolt the engine/trans back together. There is the outside possibility that air may be in the pump/hydraulic circuits and just need to bleed the system. This should happen fairly quickly. I don't know how much you have tried to drive it. If there is a loud pitched whine from the front of the trans then the pump needs to bleed air. If there is no noise then what I would do is disconnect battery, hold brake pedal 10 seconds, reconnect and attempt to drive it. Eventually it should set codes if it's an internal trans issue.

 

[loosenut]

All I said above is assuming that all wiring has been inspected for proper installation.

 

[Robotazky]

I don't know if the 5 has it or not, but my MX-3 GS has a cable from the intake to the transmission that modifies how hard it shifts based on throttle position. Might want to check into that. It's a simple fix if the problem lies within.