"Hedging" "Tugging" Transmission

I am not worried about durability of the engine/tranny its a toyota I am worried about fuel mileage.

I average 21mpg because of the way I drive I see many averaging 16mpg that extra 5mpg is 100+ miles.

No point in throwing money away but thats me........

 

my 2012 does not exhibit this. i do find that it sometimes seems to stick in 5th gear. which is a good thing for fuel economy. i like that it doesnt pop out quick like any other auto ive driven. if i need it out of 5th i just put it in 4th or mash the pedal down much further. ive only had a "wtf" momentum once while climbing a bridge upgrade and i drive that route to work, only happened once thus far.

 

My 03 prerunner frame rusted, otherwise I'd still have that truck. Never a problem with it.

 

I know exactly what you are talking about OP , definitely not gear hunting

 

I have been doing more research on this issue and found alot of info on a FJ forum.

http://www.fjcruiserforums.com/foru.../122920-shuddering-transmission-problems.html

http://www.fjcruiserforums.com/foru.../107994-my-shuddering-transmission-story.html

I dont know if the FJ and tacoma share the same auto transmission I assume they do if so it seems torque convertor replacement is the fix.

I plan on taking mine in within the next week or two for a ride along with a tech.

 

Interesting , the symptoms sound pretty similar

 

I think it's the torque converter myself

 

how about tapping the brake pedal when the tork converter kicks in to lock the converter directly to the engine . Tapping the pedal should turn the converter clutch off until you get through the slower speed . You dont need to hammer the brake , just tap it very lighty which in turn tells the computer that you are planning to stop and the converter lock up feature will disconnect. Its a matter of switching the brake switch with a very gentle touch to the brake pedal.
We use to do this with older chevy,s and Fords when a customer complained about the way the transmission shifted after overhaul to show the customer the problem was engine related and not transmission.
Its almost like Toyota commands the converter to apply lock up a little too early causing you to feel surging from the engine . This was designed this way to meet fuel economy standards .
All it would take is for Toyota engineers to design a reflash to the computer where the converter didnt go into lock up soooooo early . When the converter applies at lower speeds , its very easy to feel the slightest misfire such as crappy fuel ,crappy plug wires , is engine at operating temps etc etc .All kinds of variables come into play once lock up applies .These are but a few examples .
I am not sure re-desinging the converter will change when it goes into lock up , thats controlled by the computer . The engineers may have tried to make the application of lock up smoother by changing the friction elements on the lock up clutch itself .

I can reproduce the issue with my 2010 . Is it good for the driveline and engine- "NO"
Can it cause premature failure of the tork converter clutch lining - YES
Can it cause premature bearing failure in the engine - ofcourse .
Can Toyota fix this - Yes but will they ? the fuel economy drops by turning on the converter clutch later making their Tacoma just a bit heavier on fuel
We have the ability to drive faster or slower to keep the converter from doing this as mentioned above . In my opinion , thats how we have to work around it for now

 

About 80% of my driving is at 40-50mph , I'm gonna be tapping the brake every 10 seconds

 

I'm thinking it is the engine brake feature where the rpms increase to slow down the vehicle its not exactly a "Jake brake" as known on the diesels but it uses the engine to control the vehicle speed and you get the tugging feeling

 

No

Not unless it's trying to engine brake while you are applying throttle

 

I read this thread earlier this morning and didn't think anything of it.

On my way home from work I felt the truck tug and I looked down at my spedo and I was doing 41-42 up a slight incline and accelerating lightly.

Probably would not have thought anything of it unless I read this thread.

 

Just a thought...

 

Oh ya , wasn't trying to sound like a dick , the sensation is different than the engine braking sensation

 

When the first converter clutches were designed back in the early eighties , they were horrible , unreliable , use to shudder at 42 miles per hour , and had trouble unlocking when coming to a complete stop ,thus the engine use to stall . 90 percent of the locking converters blew apart sending a mess of metal and friction clutch material through the transmission cooling system which in turn cooked the transmission .

An easy fix to avoid this was installing an on/off switch under the dash to control the converter lock up clutch . When you are travelling on the highway , make sure your switch is on . If your driving city streets , leave the switch off and your tork converter wont lock .
Can this still be done on newer trucks ? Yes Is this a good idea ? It will cure the chugging but becuase 90 percent of the heat inside the transmission is generated by the tork converter . Leaving the converter clutch unlocked creates additional heat and costs you extra fuel .
The check engine light will also be illuminated becuase the computer is commanding the converter to lock .

The only way around this is to force Toyota engineers to flash the ecm with a more improved driveability map . With enough of us complaining , maybe they will listen ?

 

a little reading for you .
http://www.gearsmagazine.com/view.ashx?article=88d3ea95-41d0-4675-96ac-5d863f9133d1

 

Intetesting

 

My 2012 OR does this to, I have never really thought anything was wrong just more of a characteristic of the tacomas. It only ever really bothers me when I'm in traffic behind someone and cant accelerate past that magic 40 mph Threshold. Then i will feel the surging, give it a little gas and it goes away like you guys described.

 

I notice a similar "lugging" type response driving in 40 mph zones. My main problem is trying accelerate on a downgrade. The engine revs in 4th and won't go to 5th until I level out. It's very strange.

This always happens on I-65 at Hwy 52.