TCC slipping

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Topic author
KELROD
I am merely driving my van
I am merely driving my van
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Joined: Fri Oct 25, 2013 11:01 pm

TCC slipping

Post by KELROD »

I have a 2005 Astro AWD which I just put a used tranny in since the other one had burned up clutches in it and was slipping bad. After putting the used tranny in there I drove it and found that it was like I was hitting pot holes every now and then and so I suspected the tcc. Viewed the data while driving with my Genisys and thats what it was but no tranny codes. I've seen through alldata that theres a tcc solenoid and a tcc pwm solenoid. Has anyone had this problem and solution ? Thanks guys
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Drummernaut
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Re: TCC slipping

Post by Drummernaut »

You're going to have to be a little more specific.

You are talking about (TC)torque converter lock going in and out? Once you get to about 38mph the converter should lock up via the TCC valve. Using brakes, completely backing off the gas pedal, or dropping below 35mph+-? are a couple of things that make it unlock. Be sure and check your brake switch to make sure it only switches when you hit the brakes and is not short cycling because of vibration.

If you TC is slipping or bad then that would be the item to replace. Did you replace the TC along with the transmission? If so you can just get your old one back.

You say it is like hitting pot holes. Are we talking major jerk or just a little jerk? What speed(s) does this happen at?

When the TC locks, you will feel a slight jerk forward sometimes or if you listen to the RPM it will change noticeably.

Problems I have had with TCC valves are activating the lock at too low of a speed like 20mph or short cycling which may cause it to feel like being jerked back and forth. Sometimes they just die.

TCC valve problems with GM transmissions are very common and are easy to fix. Just do it at the same time you change your transmission filter. Instructions come with the valve.

Just make sure this is your problem. There is no slipping with the TCC valve but there is leaking. It is on or off causing the the TC to lock and unlock. Keep in mind that if you changed the TC along with the transmission you may have inherited a bad TC if the TCC is not the problem.

Topic author
KELROD
I am merely driving my van
I am merely driving my van
Posts: 2
Joined: Fri Oct 25, 2013 11:01 pm

Re: TCC slipping

Post by KELROD »

It happens between 50-55mph. And it can be a slight jerk or sometimes hard. Also at first the tranny had a trans fluid pressure switch code where it would tell the pcm that its in D4 rather than park and sometimes say invalid. So I replaced the switch from the old one to the new one and also replaced the harness too to eliminate both possibilities. That may not have been a good idea because it drove good before with no jerking or shudder. And you probably already know this but when you replace the harness the tcc pwm sol has to come out since the tcc is made into the harness. When I pulled the tcc pwm out it was cracked and broke when pulled out. So I took the one out of the old tranny and replaced it. So both tcc sol. were replaced and now its having an issue.
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Drummernaut
I finally get the smurf thing
Posts: 107
Joined: Sat Dec 29, 2012 1:20 am
Location: Everett, WA

Re: TCC slipping

Post by Drummernaut »

Is this the only problem you are currently having with the transmission?

If you are able to monitor the transmission with your scanner, you should be able to see when the TC locks. If that coincides with your jerking then it is safe to say you have some type of TCC solenoid problem. I would make sure it is that first before moving on.
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