buickturbot

Can anyone tell me what the last thing the 48RE automatic transmission do at around 50 mph? Do they shift into overdrive or does the torque coverter lock up. I am getting a shutter and im not sure if its the torque coverter slipping or the overdrive clutches. Fluids not burnt and its still bright red. Transmission holds the torque fine without the Smarty. Trucks sitting at the dealer and they just installed a front pump seal and gasket for a leak, but since the Smarty off it wont shutter so they say theres no problem. What this boils down to is im hopping I can just install a Gorend VB and TC to fix this problem. Im not hard on the truck but this shuttering was getting to the point that I would lift off the throttle and ease back in under normal driving.

isb07

yea at 50 mph it shifts into overdrive and locks the tc. nothing else should happen when it shifts at 50.

buickturbot

So your saying it does both?

naysayer

The shift from 3rd to overdrive is usually around 40 MPH. What feels like a shift around 50 MPH is the torque converter lock up. The shutter you're describing is the lock up clutch in the torque converter chattering.
Its time for a new torque converter.

buickturbot

That is exactly what I wanted to hear. So I should probably be able to get by with a VB and TC.