Auto Trans Slip, 4th-5th gear. Anybody Else?

Looking for info if anybody else has this, or if it is a known issue.

Recently, I've noticed when I'm manually shifting the gears (do it a lot because I haven't regeared yet and it sucks to leave it in D), I notice that when shifting from 4 to D, the RPM's surge like 100-200rpm (enough to hear it) and then it shifts up to D.

Anybody have a similar experience? It's a weird slip...it'll hold a gear no problem when mashing on it, but as soon as I throw it back into drive, it'll surge for a second or two then normal, smooth shift.

Bought the truck at 51k miles, and I have not done a transmission service yet. I've read that it's best to do it every 30k, or don't do it at all, as the trans works better with the particles in the oil. Read a few threads with people who have had negative experiences after changing the fluid.

Thanks in advance.

 

I would change the transmission oil just to be safe.

 

I get it too but I have had the weird occurance since the truck was new. I have simply dismissed it as normal as I know these transmissions are sort of quirky and have an odd shifting pattern integrated into them as they like to engine brake going down hills and downshift on steeper grades and as usual continue to hammer on the truck both on and offroad.

 

Changing the oil will not fix that. You might consider a shift kit or a modified valve body which will give it a more positive shift. Check these places out. You can call them and tell them your problem and they can advise you.
http://www.levelten.com/
http://www.importperformancetrans.com/toyota_valve_body_modifications.shtml