transmission technician

Hey guys . I am a certified transmission technician and new to the forum .
I have been out of the trade for a while , however if you have questions regarding drivetrain issues wether they be automatic or manual in nature , I can give you some half decent answers based on past experience with my backgound in the repair of Toyota transmissions ,transfer cases and differentials .
I may not know it all , but feel free to PM me should you have any issues with your drivetrain related questions that you may want answered .
I belong to many transmission based websites including a few of my own . I am more than happy to help so ask away .

 

Hi! Great. Just what I was looking for. 2003 6 AT SR5 Xcab. Bought it used 120K. About 10K ago, drained (partially) tranny fluid and replaced with special Toyota brand. Nothing else. Now got PO 741 (Torque Converter Clutch Performance/Shift Solenoid Valve SL). I get all kinds of conflicting advice on line: tranny shot, use BG, disconnect oil line and while in idle, drain all, replace filter and refill with Dexron III. Seems to occur when I have cruise control on. Some say don't touch the fluid, if dirty, it holds the tranny together.

I am really confused. Any ideals? Thanks.

 

To begin , I dont beleive your trans is shot .
Were you having issues with the transmission before you drained the fluid ?
How dark was the original trans fluid ?
Was there mutch metal and clutch material inside the pan ?
How about the magnet ? was it full of metal ?
Dirty transmission fluid doesnt hold the transmission together but may cause issues with various shift solenoids when you try to get the old fluid out .
By answering these questions you can give us a general indication of the internal condition of the transmission before we continue

 

Well, here we go:
1. Before I drained: some jerky movement after I come to a stop. Salesman said it is a truck thing. (Never had a truck before). Occasionally it would downshift on its own and rev up .
2. Fluid was dark brown. Fluid now is light brown now (only took 3 qts)
3. Did not drop the pan. Used the plug.
4. Magnet had some gook but no visible or palpable shavings or fragments.

As I said earlier, I believe the situation is partially related to the cruise control. I erased the code earlier. I drove without engaging the cruise. The transmission shifted very smoothly. Hardly perceptible, if I weren't a motorcycle rider, I probably would not have noticed. No high rpm, even on noticeable hills The tranny just shifted down smoothly. I believe it is a four speed tranny. It would go from idle reach about 2K then shift up until high gear and then stabilize, at 50 around 1750, 60 1850 and 70 2K. I just checked again, no code came up. Now if I could just keep it this way!

These data are riding the truck empty with just one passenger. I seldom carry more that a few hundred lbs.

I did not try to floor the accelerator. I'll wait until you tell me it is safe.

 

Next thing I would do is look at how the cruise control ( wiring ) circuit ties in with the tork converter clutch . If the code is tripping while you are using cruise control ,and does NOT trip while cruise is not being used , there has to be incorrect values in the converter clutch circuit . The computer (TCM ) in the truck that tells the transmission to shift sees something wrong .
Does the TCM see the converter slipping ? this is the most likely cause .
PO 741 is a terrible code to diagnose over a keyboard .
Possible causes
Low transmission fluid level
- Dirty transmission fluid
- Faulty torque converter clutch solenoid valve
- Torque converter clutch solenoid valve harness or connectors
- Torque converter clutch solenoid valve circuit is open or shorted
- Transmission internal mechanical problem
The Torque Converter Clutch (TCC) solenoid valve is activated, with the gear in D4, by the Transmission Control Module (TCM) in response to signals sent from the vehicle speed and the Engine Control Module (ECM). Lock-up piston operation will then be controlled. When the torque converter clutch solenoid valve is activated, the torque converter lockup clutch will engage creating a 1 to 1 RPM ratio between the transmission input shaft and the rotational speed of the torque converter.

Lock-up operation, however, is prohibited when A/T fluid temperature is too low.

When the accelerator pedal is depressed (less than 2/8) in lock-up condition, the engine speed should not change abruptly. If there is a big jump in engine speed, there is no lock-up.

What would I try next ? a complete transmission fluid replacement with Toyota brand fluid .
This is basicly your next step in the proper diagnosis of PO741 .
Replacing all your fluid will restore friction modifiers to the old fluid .
I would also highly recomend http://www.lubegard.com/~/C-113/LUBEGARD+Platinum+Universal+ATF+Protectant
That lubeguard is available at most transmission shops and it works absolute wonders . I have used it for years .

My 2010 TRD also moves ahead slightly when stopped at a red light . The engine also revs up when this occurs giving you the feeling that you had better push harder on the brakes . My Toyota Matrix does the same thing .Seems to be relative to all Toyota,s I have ever driven .

 

I wish to thank you for your time and effort in providing such a clear and exhaustive reply which I find extremely helpful.

You say:

"What would I try next ? a complete transmission fluid replacement with Toyota brand fluid .
This is basicly your next step in the proper diagnosis of PO741 .
Replacing all your fluid will restore friction modifiers to the old fluid .
I would also highly recomend http://www.lubegard.com/~/C-113/LUBE...ATF+Protectant
That lubeguard is available at most transmission shops and it works absolute wonders . I have used it for years "

This is what I will do next and then reevaluate the situation. It is obvious that the lock-up is working since I do get a gradual change under low to moderate acceleration. That's good enough for me for the time being. Time permitting, I will then review the sensors that the ECU needs to send proper info to the TCM. I think it may just be that. If not, then the solenoids.

I now have enough to go on. Will let you now the results. Thanks again.

 

I bought my 2006 Tacoma SR5 TRD with offroad package (locking read diffs) with 134K miles. Drives great, but sometimes there is a hard shift coming out of first. I can sometimes make it do it by braking until I am barely rolling, then hitting the accelerator. It feels like there is a small amount of slippage when I first apply pedal, then a jerk with a thud like sound.

It's done it maybe 5 times in the month I have had it. I noticed too that while idling when it's cold, it feels like it's trying to shift a bit. Not like it wants to lunge, but a slight forward movement in the drivetrain. I don't know it this is related...it feels more like a computer/injection thing, but just thought I would mention.

Note that rear diffs are OFF when this happens. I've only turned them on once.

I was going to check the fluid, but could not find the dipstick. According to the manual, this unit doesn't require any regular maintenance.

Anything I can do?

 

Hey Sporter .
Start with the basics . Your profile indicates the truck is automatic .
Do you know if the transmission was serviced before you purchased it ?
I beleive the transmission should of had a trans filter and fluid replacement at 60,000 miles .Hopefully the former owner supplied you with service records for the truck .

Start by checking the transmission fluid with the engine running in park at operating temperature .
Its normal for transmission fluid to turn a light brown in color as the fluid ages .
Transmission fluid does " not " remain red
The transmission fluid level indicator is on the passenger side of the engine compartment .
All the Toyota vehicles that I have driven have the slight forward jump when sitting at a stop light with your foot on the brake .

Is there a shop near you who offer free tests drives ?

 

Hey Gearcruncher,
My tanny behaves just fine at start up. Later at full operating temp it shifts hard coming out of 1st into 2nd. My fluid level seems fine. I changed the filter and fluid about 10.000 miles ago. i did not do a complete fluid flush only drained the pan and refilled to proper level. Can you help?
2.7l 4x4 auto

 

Question for gearcruncher:
I have a 2011 reg cab 4x4 manual trans. I bought the truck wrecked in the front.My brother repiared the truck. the left front whell was replaced indicating a hard hit there. When I drive the truck up to about 63 mph I hear and feel a humming / vibration from the front I think. I am thinking a bad wheel bearing or cv axle or differential. When I jack up the front and turn the drivers side front wheel I hear a clicking sound which appears to be coming from the area where the axle goes into the front diff. I am looking for any ideas of how to find the problem.
Thanks

 

Question for gearcruncher:

I have a 1999 4runner limited with a340 transmission. The cooler blew
and it got radiator water in it, and the tranny started to fail to shift...

so I had it 100% uninstalled, benched, and rebuilt

all new O-rings, retaining clips, gaskets, brakes, clutches, bands, torque converter, solenoids.
(and a new radiator) new pan, filter, and also dipstick tube (part of pan)

about as total a rebuild as you can get except for the gears, they were all fine

it was also sandblasted and painted
----
It is back together now and it is running MINT.

However, there is something different:

Original behavior : cold start, drive away, no delay on upshift to overdrive

New behavior: acts like a newer Toyota, and refuses upshift to overdrive
until it has warmed up a bit (few minutes). But it acts perfect (and since this now acts like
newer toyotas where there is a longer wait before overdrive will occur, I don't see it as a problem)

Question: what changed to introduce this little 'delay-until-warmed-up' ? was the tranny
ECU reprogrammed or it is a change in part number or sensor ?

 

Welcome to TW Gearcruncher! Nice to have a fellow ASE trans tech on TacomaWorld. Good advice on here. On Recon's truck, his is a 1st gen, so his TCM and ECU are all inclusive in one. There is no separate TCM on the 1st gen Tacoma trucks.

 

Hey guys , just got back from an extended vacation . Sorry I havnt been around much . I will try and answer your questions to my best knowledge .

 

Hey gear cruncher, i have a 2007 4.0 Tacoma. It makes a slight vibration sound in first gear when i take off. It almost sounds like driving over a wash board. It also make the noise when i hit the brake to slow down. It seems to only be happening in first gear. 95,000 miles never been serviced. Thanks for your time.
Any help appreciated.

 

I have a 99 Tacoma pre runner extended cab. It has 140,000 miles.Been a good truck only MAF issues. I have changed or had the transmission fluid changed about 4 times in its life. I recently had it changed at the dealer. It seems to have developed a chunking, lagging, or not fully engaged thud when I apply brakes or from a standing start. Maybe its normal, I dunno. Sort of like a broken motor mount, or like the drive shaft is moving foward or backward. The gear shift(automatic) moves when this happens too. This may or may not be a transmission issue may even be normal but it seems more pronounced lately. It could be that I have been working on my wife's Honda tranny(pressure switches,and solenoid valves) and I'm having delusions. Anybody else have this kind of issue, or is it normal???
Thanks, David

 

Hey gear cruncher I have a 06 tacoma that had the 4wd and 4wd LO lights blinking at me. I took off the front diff ADD and checked and nothing was found it was clean as a whisle. I still soldered the switch part and the connection to the motor actuator. It's still blinking. Next I put the truck in jack stands and turned it on and in. 4wd the front drive shaft doesn't even spin. How to I trouble shoot if it's a bad transfer case or front diff actuator? Or maybe even the switch in the dash thanks

 

Hello and thank you for allowing us to us to test your knowledge. I have a 2004 v6 auto trans with 130ish thousand miles on it with as far as i know no services so far. I never had any troubles with it at all until i got into a wreck. After about 10k of work done to it it drives great with one exception, my xmsn. When im driving, the shifter will move around while still in gear making all sorts of clicking noises. it doesnt fall out of gear and still shifts smooth...ish, but i dont want this to turn in to a bigger problem down the road. If you have any clue as to what could be the issue i would love to hear it. I really dont want to take it into a shop blindly and have them take every penny i have. Again thank you for your help.

 

Hey GearCruncher,
Thank you for offering so much good advise. I was wondering if you could give me your opinion on my first step in fixing the issue I'm having. I have an 06 Tacoma 4.0 with almost 119,000 miles.

I recently noticed a "shudder" or slight vibration at the end of 3rd and the end of 4th gear when accelerating medium to slowly. I haven't noticed it as much when I'm pushing the pedal harder.

When I took it to the dealership to diagnose it (and I needed my spark plugs and oil changed) I don't think they really looked at the transmission, they just said they could replace for a new transmission. They don't rebuild or replace parts.
Do you think it is worth getting an Auto. Trans. Fluid Flush now, or anything to bring life back to it? Or is it about time to find a rebuilt or new one and someone to put it in? Also, I don't think it's related but my AC has been making a knocking noise at start up when the recycle air is on, when off its quiet.

Any suggestions would be most helpful, thanks for your time!

 

Got some reading for you to base an opinion and learn about your truck here :
http://www.tacomaworld.com/forum/te...hift-kit-shift-recalibration-kit-2nd-gen.html

 

Thanks man, I've finally got the dealership to change out the fluid a few weeks ago and monitored it over that time. It seems to shift much better, and I am not noticing the shudder anymore. I did a little right after it was done, but no more shutter as I can tell. I was really worried because I've heard flushing can sometimes make it worse.
I looked around for that Lubegard and picked up the red bottle, couldn't find the platinum. And I can't find any info. on how much of the bottle to add. It says 1oz per qt. of ATF, but everyone is just adding fluid until the color changes. So I cannot figure out a number, I'm guessing 8oz.
So do you think this Red bottle of ATF Protectant is good enough, or should I find the platinum? How much should I add? And where's the best place to fill it? Sorry I'm so clueless, haha