Loss of acceleration, Transmission?

[Camd3nn]

I drove to work one morning and everything was completely fine a couple days after replacing my radiator with a oem one (mentioning because it has the transmission cooler in it) Then I go to leave for work and my power delivery is close to nothing, I can feel something spinning at what feels like the correct speed for the RPMS I’m at but there’s barley any acceleration. It also takes about 10 seconds to drop into gear and back to neutral and slips gears pretty bad while driving, reverse works just fine and torque feels normal with center diff locked and in low in drive. fluid is definitely a little dark but levels are good.

Would love any insight or diagnosis procedures you guys can recommend to get closer to figuring out what it could be.
It’s a 2000 lx470 with the a343f and 260k miles

 

[TLCPNW]

First thought: did you top off the transmission fluid since you lost some that was inside your old radiator? Check your fluid level first (follow the directions in the owners manual.. Essentially bring it up to operating temperature (150-175ish) and check the level while it's running and in park and top off accordingly through the dipstick tube).

 

[TahoeZ]

These transmissions are very sensitive to fluid level. If setting correct level doesn’t correct the issue recommend full fluid exchange then set level at operating temperature.

 

[Camd3nn]

First thought: did you top off the transmission fluid since you lost some that was inside your old radiator? Check your fluid level first (follow the directions in the owners manual.. Essentially bring it up to operating temperature (150-175ish) and check the level while it's running and in park and top off accordingly through the dipstick tube).

Yes topped off after, checked levels twice and ran just fine for a few days

 

[2001LC]

Yes topped off after, checked levels twice and ran just fine for a few days

If I read correctly. Your RPM went up but speed did not. You also had delay going into gear, from P to D. Started after rad R&R.

Did you plug AT cooler lines, while R&R AT.
Or
Did you just let ATF drip out.
We lose some from what remaining in rad cooler and some dripping. If already low AT, than now you may be to low.

Make sure coolant is to top of rad. Check in AM before sun-up (warms air) or first start-up. Check on level ground or better yet; front end high.

Assuming you did check level of AT fluid properly. AT fluid at opt temp, idling, shift through all gear, level ground. Then next :

1. Look at all wiring on AT. Look for anything that doesn't look right and or rodent chew.
2. Also make sure no water entry from bad windshield install.
3. Try manual shifting. If then shift good, likely electrical issue.

All as should be, and manual shift no help:
I'd do a full 12qt flush with Mobil One MV ATF (98-02 100 series).

 

[hoser]

...reverse works just fine and torque feels normal with center diff locked and in low in drive. fluid is definitely a little dark but levels are good.

How does it feel in High Range, in Drive and CDL on?