Torque Converter Lockup Issue?

So I'm getting a bucking and jerking like feeling at lockup (about 50 mph, 1600-1800 rpms). Happens only with OD on. Test drove it while paying attention to the transmission lockup PID and figured it's got to be a torque converter / lockup problem. It's the holidays so figure I won't take it to the transmission shop until next week but was wondering if anyone has had any issues like this and how much was it to fix it? I'm hoping I don't need a full rebuild. Was contemplating dropping the transmission pan and testing the solenoids. From what I understand they're all right their at the pan for an '02 V6 5VZ. At least I hope so.

 

Take it for a drive when the truck is cold . Will it buck and fart cold ?

Grab a pen and paper . Watch the tachometer and record the rpm when you feel the bucking .
Now go in your driveway when the engine is warm , hold the brake pedal hard , put the truck in drive and slowly bring your engine rpms, up to the same rpm where you fealt the bucking when you were driving down the road .
Do you feel the engine misfire at the same rpm ?
Allow the transmission to cool after this by placing the trans in park and idling for a while .
This is called a stall test . A stall test eliminates the torque converter from being the problem . The converter does not come on in first gear . A stall test is performed to reproduce the engine load without moving the truck

 

I will try my best to answer here . The messages that go to my inbox are also replied to as well but Tacoma world doesnt get to see them '

These are only symptoms of a converter clutch problem . 99 % of the time , its an engine problem creating a torque converter symptom
Need the mileage ? Type of fuel you are running ?
Last engine tune up ?
Spark plugs , spark plug wires , any codes popping up ?

 

Yes to your previous question - does it on cold start.
160K miles, 87 oct, no codes, haven't done plugs and wires since I've owned it for a couple of years. Will do those when I take care of the valve cover gaskets but I know for sure it's not a misfire issue if that's where you're going. It's definitely mechanical in nature.

 

converter clutch is probably worn out. how does the fluid look?

 

Converter clutch does not come on until engine is completely warmed up .
Converter issue eliminated .
You need a good engine tune up .

 

I will add ,
an ice cold engine that recently started does not upshift into 4th gear or go into converter apply until the engine is completely warmed up . If the truck is jerking and bucking before the engine is completely warmed up , you need to look at engine related issues before the torque converter .
I believe you are feeling a symptom of a faulty locking converter .
There are tests we can point you towards to eliminate the converter completely , but as far as I am concerned from your explanation , you are in need of engine tuning

 

Red, not burnt.

 

I live on dirt roads and have to drive for about 7 minutes before I can even get to a road where I can get it up to speed so when I say it does it on 'cold start' it's in quotes. ;-)

 

OK , the engine has most likely warmed up by then .
This being said , we can move up to a stall test in your driveway when the truck is warm .
You dont have to move the truck , just put the truck in gear when warm and hold the brake hard and slowly increase the gas pedal .
We know you are feeling the jerking between 1600-1800
What happens when you hold the brakes hard and slowly bring your rpms up to 1600-1800 ?
Do you feel the engine missing ? Its not going to feel the same as driving down the road , but you will feel stumbles in the engine rather than being smooth .
This is what the transmission shop is going to test when you bring it to them to check . I do this test on a daily basis for all my customers with similar complaints .
Once again , allow the trans to cool after you perform the test .
Finish this test and we can move on to the next test if needed

 

could be the torque converter clutch solenoid...don't have much experience diagnosing those but they are cheap.

 

Just got done with the test... it feels and sounds like an occasional clunk - like the tranny wants to engage but doesn't. Clunks, two seconds later clunk, two seconds - clunk etc..

 

Did you feel the clunks at 1600 to 1800 rpm ?
The idea behind a stall test is to reproduce the symptoms under the same " Engine Load " in your driveway .
If you feel bucking at 1600-1800 rpms in your driveway without moving the truck , there is a darn good chance we just eliminated the torque converter .
The converter does not apply in first gear .

 

Yes, it was in that RPM range.

 

Spark plugs and wires, coil packs are a lot cheaper than a torque converter replacement .
I do hear horror stories of guys taking their trucks to transmission shops for this problem and getting a full rebuild when all they needed was an engine tune up
Tread carefully .
I highly suggest starting with an engine tune up .
I believe plugs and wires on your truck are slotted for every 30K by Toyota .
If the tune up doesn't solve the problem 100% , we may have to re-visit more testing for another small issue , but I am convinced at this point you need engine tuning

 

Fair enough. Is there anything else I can check transmission wise in the meantime?

 

Baby steps in automotive .
An engine tune up first
The idea behind Tacoma World is to come together as a group of enthusiasts who all love their trucks and try to save fellow members some hard earned cash .

 

there is a slim possibility that a loose/malfunctioning brake light switch will cause the torque converter to “unlock” but only when the parameters to lock the converter have been met, it is designed to unlock during braking if it is locked.

 

This is very true
I didnt want to confuse him with a " Brake Tap Test " , but he could try it for giggles
After the engine tune up , we could always follow up with the brake tap test .

 

So by the feel of it I would've never guessed a plugs and wire issue but it did clear it up. I still get some clunks with your power breaking procedure but am not getting the bucking at lockup speed anymore.