Torque Converter Problems

Ok guys... I wanted to start this thread to gain some insight as to why my torque converter has gone bad three times in the last 3 years...

Mine is a 2007 V6 automatic. 158k

I normally just do city driving (stop and go). Rarely take it offroad or on the highway for longer than 25miles or so. Drive less than 50 miles a day.

Basically... has anyone here dealt with bad torque converters? If so, what normally causes them to go bad on these 2nd gens? All my drivetrain/powertrain is stock.

First time it went bad Toyota swapped out the whole transmission assembly and replaced it with another one under warranty. Last time about a year ago I took it to a local transmission place (where it is once again today.)

Any feedback would be greatly appreciated. I just really want to know what causes these to fail. Thanks in advance

 

There was a another thread on here where someone mentioned that radiator fluid was getting into the trans from the trans cooler. Maybe have the fluid tested for antifreeze?

 

That is a lot of failure on the same thing. Towing heavy loads can cause them to fail. Over heating can also. Also low fluid levels. Trash entering the torque converter. My question is what part of the converter is failing? The bearings, stator or the fins or everything? You need to ask your mechanic what failed in the torque converter and his opinion as to why. I hope it is still under warranty from last time.

 

What was it doing? Why did they think it was the problem?

 

So the TC is still under warranty from last time.

What I'm experiencing is "shudder" at low RPM's when the truck is trying to upshift. For instance: right before it shifts from 2nd to 3rd my whole truck will shudder violently (almost like the driveshaft is shaking). I've heard this is the TC trying to lock up and slipping instead...

It also is very rough off a dead start. Also experiencing a loss of power at this point.

 

OK that makes sense. Isn't there a ECM flash for that? If the converter is going into lockup at too low a speed it's bound to shutter.

 

Interesting... any links or references for said flash? Every time they've worked on the transmission I've been told they had to reflash the ECU. But then again, every time they've worked on it thus far the TC has eventually gone bad.

I just wonder what causes it to go bad after some time. Makes me wonder if it's something I'm doing

 

I will share what happened with my wife's 07 fj, we bought new, never towed, never four wheeled. It would studder when shifting from second to third gear. Got 3 estimates, torque converter replacement, transmission replacement. I refused to do anything, wife drove it for two years with a lead foot and it would do fine. Alternator went out, I replaced it and have driven 20k with no problems what so ever .

 

I can believe that more throttle will make it shift latter at greater speed.

 

This is also true with mine. If I feel it start to shudder, I just adjust how much throttle I'm giving and it goes away-- It only shudders when I drive it normally. But I hate making the transmission shift more than it needs to.

Update: Transmission shop BS'd me yesterday saying this was a motor issue. It is now at Toyota getting a second opionion. Can't wait to throw it back in their face when Toyota says its the transmission again

 

Are you positive that it's the transmission and not the drive shaft shaking? There are a ton of threads about vibrations and shutters caused by the mis-designed drive line. I had a moderately bad shutter in mine and it turned out to be the carrier bearing was letting the drive shaft move too much, causing the truck to shake. There is also a TSB out for an updated rear engine mount (Toyota calls it an engine mount, it's actually the mount for the transfer case) and it is aimed at vibrations and shutters. I guess I'd make sure it's actually the transmission.

 

The Aisin 750 units in the 2nd gen trucks have a good track record.
I had a bad vibration in my '06 at one point and was sure it was a transmission until I did more digging. Turns out I had to rebuild by driveshaft. Problem was gone once that was accomplished. Smooth as glass with new u-joints and carrier bearing.

 

You need to drive the truck with the dealer mechanic in the passenger side . He holds the techstream while you duplictae the problem . Without a scanner , its almost impossible to diagnose vibrations or pinpoint vibrations over a keyboard .
Newer transmissions are designed to save fuel and will partially lock the converter in lower gears .
Sounds like round 3 here ? each time the converter was replaced , the vibration went away ?
What failure happened to the 1st and 2nd converter ? They can be cut open for diagnosis . Was the valve body overhauled/ replaced during the 2nd converter installation or did they simply replace the converter this time ?
My guess is a valve body or pcm issue .
If you are at an aftermarket shop having your transmission diagnosed , here is some usefull information that may help avoiding this problem again . I would suggest reading through the links and questioning the shop in regards to some of the known fixes listed in the links posted here .
http://www.tacomaworld.com/forum/te...hift-kit-shift-recalibration-kit-2nd-gen.html

147741-01K Boost Valve Assembly Toyota
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147741-05K Oversized Solenoid Modulator Valve Kit Requires F-147741-TL5 Tool Kit & VB-FIX Reaming Fixture Toyota
Oversized Lockup Relay Valve Kit Requires F-147741-TL7 Tool Kit & VB-FIX Reaming Fixture Toyota 147741-10K
Oversized Secondary Pressure Regulator Kit Requires F-147741-TL4 Tool Kit & VB-FIX Reaming Fixture Toyota 147741-16K
Oversized Lockup Control Valve, Plunger Valve & Sleeve Kit Requires F-147741-TL16 Tool Kit & VB-FIX Reaming Fixture Toyota
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I'm not positive but I'm about 90% sure. It has done this before and the problem was the torque converter. Before they determined it was the torque converter, they thought it was my driveshaft. I had the whole thing replaced along with a new carrier bearing. I haven't heard anything about a motor mount TSB but since mine is a prerunner it looks like it won't apply to me.

Still waiting to hear back from Toyota about their diagnostic today...

 

Here is a list of the work they did last time word for word from the receipt... a whopping $3500 worth

-Remove overhaul and replace transmission
-Complete overhaul package w/ steel plates, clutches, seals, rings, gaskets, bushings, thrust washers, filter
-Recondition of torque converter
-Recondition of valve body & solenoids
-Recondition of gear train


Let me know if any of this sounds out of the ordinary or unnecessary

 

Believe it. Auto transmissions control when the transmission upshifts, and one of the most important signals is the throttle position sensor. The more throttle you give it, the longer it waits to shift.

It is not surprising that a transmission shop might think it is engine related. A misfire that occurs only under load would be most prevalent when driving moderately, and the transmission upshifts. At that point the engine is under load with the RPM in a low horsepower range. This is when a misfire is most often going to occur. Of course you are most likely right, but I just wanted you to understand why someone might think it was an engine misfire, especially after all that has already been done to it.

 

Quote:
Originally Posted by maineah View Post
I can believe that more throttle will make it shift latter at greater speed.
Believe it. Auto transmissions control when the transmission upshifts, and one of the most important signals is the throttle position sensor. The more throttle you give it, the longer it waits to shift.

The key word was "can" and the governor kinda has a role in this too.

 

Just picked up my truck from Toyota and guess what... TRANSMISSION PROBLEM. They didn't tear anything apart but I went on a ride with the tech and he determined without a doubt it's the transmission causing all of this. $65 for the diagnostic


Taking it back to the transmission shop on Monday with Toyota's report. Should be an interesting day.

 

Thanks for the update. I'm looking forward to hearing what they say at the transmission shop. I still have this feeling that the ECU is at fault. Just a feeling mind you.