Transmission slip/delayed engagement in 1st

[Zer0zg]

Hey guys,

My '04 LX has developed some odd behavior in 1st gear. When moving from a stop or shifting in to D, the transmission seems to slip and catch in 1st gear, ie requires more throttle/rpms to get going than would be normal. Once it catches it behaves fine and all other gears are fine. Thinking it might be fluid level or condition, I just did a full fluid replacement with Aisin WS, got it to temp and set the level, which appears to have had no effect, though it was definitely due.

One odd thing I just noticed is that it does NOT do the same behavior when put in to L. If I run through all the gears manually it's totally fine. This does indicate that it's less likely to be something mechanical in the trans, but would this be true if the problem was a shift solenoid?

Thanks for the help.

 

[Malleus]

Sounds like your clutches are worn. My 2000 has the same problem. The rebuild kit is on the shelf, waiting for warmer weather.

 

[Zer0zg]

Actually, just ran the OBD (did not have CEL) and came up with a pending P0751 Shift Solenoid “A” Performance/Stuck Off

That led me to this thread, with very similar symptoms. Checked the connector, and two of the pins came away with the connector as it was quite corroded inside. I suspect this is the origin of my problems. I had a different intermittent shifting issue into 2nd a while back that self resolved, but sounds like that was this connector going bad as well

Now to source both ends of the connector....

 

[Mike NXP]

Sounds like your clutches are worn. My 2000 has the same problem. The rebuild kit is on the shelf, waiting for warmer weather.

But if they put it in L manually it drives just fine so wouldn't that indicate a different problem? Has anyone else out there ever had failed clutch pack in the auto trans on the 100 series? Seems less common.

Actually, just ran the OBD (did not have CEL) and came up with a pending P0751 Shift Solenoid “A” Performance/Stuck Off

That led me to this thread, with very similar symptoms. Checked the connector, and two of the pins came away with the connector as it was quite corroded inside. I suspect this is the origin of my problems. I had a different intermittent shifting issue into 2nd a while back that self resolved, but sounds like that was this connector going bad as well

Now to source both ends of the connector....

Nice find, maybe post a picture of the connector / connections so we can check it out.

 

[Zer0zg]

Best I can do for now, both ends are still in the truck, you can see the pins still in the female connector though. I could feel higher than normal resistance trying to get it loose, and usually these lever locked connectors are super easy to remove.

 

[Mike NXP]

Shoot, I'll bow out of this one...I'm not sure the best way to get that done. I'm sure there is some sort of tool to help get those pins out but not sure how to go about a replacing / fixing it all.

 

[Zer0zg]

yeah, I found a used external trans harness on eBay for $85 out of an 86k mile truck, figure that's worth a shot considering the OEM new ones is 400+. There are stand alone connectors available online but they all have tails for butt connecting all the wires, which I'm not gonna do. Not sure how friendly this connector is to repinning, but if this eBay one looks decent I'll probably just send it. If not I guess I'll see about swapping connectors.

The trans side requires dropping the pan, so I'll likely replace the S1 solenoid while I'm in there.

 

[Malleus]

But if they puts it in L manually it drives just fine so wouldn't that indicate a different problem? Has anyone else out there ever had failed clutch pack in the auto trans on the 100 series? Seems less common.




Nice find, maybe post a picture of the connector / connections so we can check it out.

You mean, other than me?

Yeah, the 2000 model year was produced in twice the numbers as all the other years, and has twice the rate of transmission failures.

 

[Malleus]

Actually, just ran the OBD (did not have CEL) and came up with a pending P0751 Shift Solenoid “A” Performance/Stuck Off

That led me to this thread, with very similar symptoms. Checked the connector, and two of the pins came away with the connector as it was quite corroded inside. I suspect this is the origin of my problems. I had a different intermittent shifting issue into 2nd a while back that self resolved, but sounds like that was this connector going bad as well

Now to source both ends of the connector....

The repair procedures and part numbers are in the Wiring Harness Repair Manual, in the Resource section. You'll need a version at least as old as your year model, and newer will work too.

 

[saucebox]

Your connector should have 5 digits printed on it. Toyota part numbers for them always begin 90980-xxxxx, and the last five are the printed digits. it'll come without pins, and you can buy pre-pinned wires from Toyota too (but that just goes right back to butt-connecting/soldering to your existing harness, so I usually don't do that.)

I've used Ballenger Motorsports to find the correct pin in the past—I just give them the Toyota connector number, and they tell me which pins I need to get. They're usually pretty cheap, like a few cents each. De-pin the old connector, replace what pins are too corroded to work, get back on the road.

In your case though I might still keep an eye on that eBay harness—no telling how far the corrosion wicked up the wire. It shouldn't be bad...

 

[Zer0zg]

Your connector should have 5 digits printed on it. Toyota part numbers for them always begin 90980-xxxxx, and the last five are the printed digits. it'll come without pins, and you can buy pre-pinned wires from Toyota too (but that just goes right back to butt-connecting/soldering to your existing harness, so I usually don't do that.)

I've used Ballenger Motorsports to find the correct pin in the past—I just give them the Toyota connector number, and they tell me which pins I need to get. They're usually pretty cheap, like a few cents each. De-pin the old connector, replace what pins are too corroded to work, get back on the road.

In your case though I might still keep an eye on that eBay harness—no telling how far the corrosion wicked up the wire. It shouldn't be bad...

Yeah, I went ahead and ordered the Ebay harness which just arrived. If the old connector were in a place where I could repin the connector without removing it from the car then I would have just replaced the connector, but the price for a used harness was low enough that if I'm pulling it anyway seems easier to replace the whole thing.

I did pull the plastic cap off of the new harness's connector to inspect the female pins and they look fine, so I suspect I'll be be in good shape once the internal trans harness arrives. Gonna take the opportunity to do the filter as well.

 

[Zer0zg]

5 hours and 3 broken oil pan bolts later, I’m done and that connector was definitely the problem, it shifts great now, no hesitation in 1st. Also, was nice to see virtually nothing on the magnets in the pan so I think the trans is in decent shape.

 

[shtbrwn86]

5 hours and 3 broken oil pan bolts later, I’m done and that connector was definitely the problem, it shifts great now, no hesitation in 1st. Also, was nice to see virtually nothing on the magnets in the pan so I think the trans is in decent shape.

Glad you got it sorted out. Great troubleshooting! How many miles on the rig BTW?

 

[Zer0zg]

Glad you got it sorted out. Great troubleshooting! How many miles on the rig BTW?

Thanks, luckily they’re a always someone on the internet who has had your problem before, and 205k.