Random A/T questions

[1GenDSM]

1) I notice that I dont have overdrive while driving on a cold start. It usually takes 30-60 seconds before it appears. I know several other vehicles do this as well, so I'm guessing this is normal? If so, what regulates it? Trans fluid temp?

2) What are the signs of a failing torque converter? And what exactly fails inside?



I'll post more questions as I remember them...

 

[transdude]

1) I notice that I dont have overdrive while driving on a cold start. It usually takes 30-60 seconds before it appears. I know several other vehicles do this as well, so I'm guessing this is normal? If so, what regulates it? Trans fluid temp?

It's fine and I believe it is more of and engine temp thing.

2) What are the signs of a failing torque converter? And what exactly fails inside?

It is usually noisy in gear but the symptoms vary based on what is wrong. Internal failures are usually the bearings or the t.c. clutch.

-John
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[1GenDSM]

So what's the reasoning behind limiting the overdrive gear based on temp?


I've noticed that cruising RPM at a given speed can vary up to 300 RPMs between a cold converter and a warm converter. Is that normal or is it a sign of a converter issue? Also, it sometimes takes the converter a second to "engage" when taking off from a dead stop. I doubt that's normal, but I don't know what could cause it either.

 

[transdude]

So what's the reasoning behind limiting the overdrive gear based on temp?


I've noticed that cruising RPM at a given speed can vary up to 300 RPMs between a cold converter and a warm converter. Is that normal or is it a sign of a converter issue? Also, it sometimes takes the converter a second to "engage" when taking off from a dead stop. I doubt that's normal, but I don't know what could cause it either.

The delay in overdrive and tcc lock-up (your 300 rpms) is to enable the vehicle to warm up a bit quicker and not feel like crap when the converter clutch locks with a cold engine.

As far as the other issue, I doubt it is converter related as a converter is always "engaged".

-John
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[1GenDSM]

Thanks for the help man!

One more thing - Can you explain the details of tcc lock-up? How does it physically work, and when?

 

[transdude]

Thanks for the help man!

One more thing - Can you explain the details of tcc lock-up? How does it physically work, and when?

http://www.dsmtuners.com/forums/articles-drivetrain/110891-torque-converter-operation-explained.html

-John
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[1GenDSM]

You're the man! That's exactly what I needed to read.

 

[91Bomb]

Do AWD 1g's have lock-up torque convertors? Because my FWD turbo 1g didn't have it.

 

[transdude]

Do AWD 1g's have lock-up torque convertors? Because my FWD turbo 1g didn't have it.

1G's are non-lock up

-John
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