V6 engine shakes @ low-RPM high-gear OD

Can anyone point me in the right direction? I know this has been discussed a few times but I need an immediate solution... I was running 87 octane and upgrading to 92 didn't solve this.

It happens mostly around 40-50 mph @ 1300-1500 rpm, the whole truck just shakes like crazy, if I rev it up a little more it goes away.

 

Automatic trans:
Could be the trans. I had a Ford Escort that was like that... it was the torque convertor clutch stuttering.
Also common on the 4L60E in Chevy trucks.

Manual trans:
You should not be loading the engine at 1300-1500rpm. At 40-50, you should not yet be in OD unless just cruising level or downhill.

 

Mine does the same thing.

I wouldnt say it "shakes like crazy" but there is a definite viration. I am no expert but my guess is that when in D(rive), the transmission likes to go into the OD gear around that speed and stay there. When you come up to a hill or have a slight drop or increase in speed, that OD gear struggles during that delay until it figures out it needs to downshift.

If I am on a road where 40 mph is common, I take it out of OD. That seems to help. It is annoying though. Just another reason why I hate automatic transmissions.

The experts on here will know better than me though...

 

Yeah its an auto trans, though you're right, it doesnt do it if I take off the OD.

 

Ya... the trans shouldn't be holding in OD under load, but at the same time, you shouldn't have to manually hold it out of OD... the TCU should be handling that.

If you give it just a little more gas, does it downshift and clean up? Being an '05, I'd consider a trans fluid change. Your V6 will take Toyota "WS" fuid... not Dex-III/VI or Toyota T-IV. Not sure about availability in Mexico (or for that matter, how far from Cabo the nearest Toyota dealership is!), but this is definitely not something I'd trust to an independent shop.

 

yeah it downshifts with a bit more gas... sounds like Im stuck with this.

 

I don't know anything about this transmission, so I'm curious to hear if anyone has a fix. Can the shift points be reprogrammed through the ECU? Some aftermarket remap? I know that the reason the auto gets better average mileage is because it is constantly trying to work you into a higher gear to keep RPMs down. This situation seems out of spec though.