Reverse to Drive - Loud Tranny Clunk
Thread Starter
Teching In
Joined: May 2010
Posts: 32
Likes: 0
From: Joshua, TX
Reverse to Drive - Loud Tranny Clunk Over the past 4 months, my GXP has developed a loud and fairly harsh clunk when I shift from reverse to drive. It's almost as if one of the mounts are destroyed...but ALL mounts are in perfect condition with no excess play or cracks in them. Is anyone else experiencing this, and is this really considered normal? I've already flipped the dog-bone mount, and there is not too much movement of the engine when holding the brake and applying torque.
My local GM dealer says that's perfectly normal for a LS4 car. I took it in for hard knock upon startup, and they're replacing the lifters iin it now. They took the tranny apart to see what could be causing it....even the head tranny service tech agreed that the clunk was NOT normal. With it apart, they see nothing that is causing it, and again, according to GM, this IS normal. They had an 2008 Impala SS in there as well for an oil change, and they said that it did it as well.
Regardless, after some lengthy talks with the head tranny service tech dude, he opted to do a few things in the valve body to increase the line pressure, and firm up the shifts. I'm kind of interested to see how it does.
My '99 Regal GS did NOT do this ever. My GXP has 61k miles on it now.
My local GM dealer says that's perfectly normal for a LS4 car. I took it in for hard knock upon startup, and they're replacing the lifters iin it now. They took the tranny apart to see what could be causing it....even the head tranny service tech agreed that the clunk was NOT normal. With it apart, they see nothing that is causing it, and again, according to GM, this IS normal. They had an 2008 Impala SS in there as well for an oil change, and they said that it did it as well.
Regardless, after some lengthy talks with the head tranny service tech dude, he opted to do a few things in the valve body to increase the line pressure, and firm up the shifts. I'm kind of interested to see how it does.
My '99 Regal GS did NOT do this ever. My GXP has 61k miles on it now.
Staging Lane
Joined: Sep 2008
Posts: 51
Likes: 1
Mine does this as well and clunks pretty good in manual mode when you shift into first. In fact mine is starting to clunk shifting into first even not in manual mode when i come to a stop. While I dont think its normal or right it seems common among these cars. My tranny is on its way out I am pretty sure as I get issues with the car wont move until it get reved a little then slams into gear just sitting at lights or shifting into drive. Its done it off and on for the last 5 to 10k miles but seems to be getting worse. I hope to get it replace, put a tranny cooler in and get a tune soon after if I do get it replaced under warranty.
Over the past 4 months, my GXP has developed a loud and fairly harsh clunk when I shift from reverse to drive. It's almost as if one of the mounts are destroyed...but ALL mounts are in perfect condition with no excess play or cracks in them. Is anyone else experiencing this, and is this really considered normal? I've already flipped the dog-bone mount, and there is not too much movement of the engine when holding the brake and applying torque.
My local GM dealer says that's perfectly normal for a LS4 car. I took it in for hard knock upon startup, and they're replacing the lifters iin it now. They took the tranny apart to see what could be causing it....even the head tranny service tech agreed that the clunk was NOT normal. With it apart, they see nothing that is causing it, and again, according to GM, this IS normal. They had an 2008 Impala SS in there as well for an oil change, and they said that it did it as well.
Regardless, after some lengthy talks with the head tranny service tech dude, he opted to do a few things in the valve body to increase the line pressure, and firm up the shifts. I'm kind of interested to see how it does.
My '99 Regal GS did NOT do this ever. My GXP has 61k miles on it now.
My local GM dealer says that's perfectly normal for a LS4 car. I took it in for hard knock upon startup, and they're replacing the lifters iin it now. They took the tranny apart to see what could be causing it....even the head tranny service tech agreed that the clunk was NOT normal. With it apart, they see nothing that is causing it, and again, according to GM, this IS normal. They had an 2008 Impala SS in there as well for an oil change, and they said that it did it as well.
Regardless, after some lengthy talks with the head tranny service tech dude, he opted to do a few things in the valve body to increase the line pressure, and firm up the shifts. I'm kind of interested to see how it does.
My '99 Regal GS did NOT do this ever. My GXP has 61k miles on it now.
Mine does this as well and clunks pretty good in manual mode when you shift into first. In fact mine is starting to clunk shifting into first even not in manual mode when i come to a stop. While I dont think its normal or right it seems common among these cars. My tranny is on its way out I am pretty sure as I get issues with the car wont move until it get reved a little then slams into gear just sitting at lights or shifting into drive. Its done it off and on for the last 5 to 10k miles but seems to be getting worse. I hope to get it replace, put a tranny cooler in and get a tune soon after if I do get it replaced under warranty.
Teching In
Joined: Aug 2010
Posts: 20
Likes: 0
Mine does have a somewhat loud clunk when shifting into any gear really. I had a loud clunk WOT shifting 1st to 2nd tapshift for the first time a couple days ago. Mine does the same thing at a stop... shudders then clunks. I'm afraid to ever get on it anymore. 
TECH Enthusiast
Joined: Apr 2007
Posts: 697
Likes: 0
From: Hudson River Valley, NY
Over the past 4 months, my GXP has developed a loud and fairly harsh clunk when I shift from reverse to drive. It's almost as if one of the mounts are destroyed...but ALL mounts are in perfect condition with no excess play or cracks in them. Is anyone else experiencing this, and is this really considered normal? I've already flipped the dog-bone mount, and there is not too much movement of the engine when holding the brake and applying torque.
My local GM dealer says that's perfectly normal for a LS4 car. I took it in for hard knock upon startup, and they're replacing the lifters iin it now. They took the tranny apart to see what could be causing it....even the head tranny service tech agreed that the clunk was NOT normal. With it apart, they see nothing that is causing it, and again, according to GM, this IS normal. They had an 2008 Impala SS in there as well for an oil change, and they said that it did it as well.
Regardless, after some lengthy talks with the head tranny service tech dude, he opted to do a few things in the valve body to increase the line pressure, and firm up the shifts. I'm kind of interested to see how it does.
My '99 Regal GS did NOT do this ever. My GXP has 61k miles on it now.
My local GM dealer says that's perfectly normal for a LS4 car. I took it in for hard knock upon startup, and they're replacing the lifters iin it now. They took the tranny apart to see what could be causing it....even the head tranny service tech agreed that the clunk was NOT normal. With it apart, they see nothing that is causing it, and again, according to GM, this IS normal. They had an 2008 Impala SS in there as well for an oil change, and they said that it did it as well.
Regardless, after some lengthy talks with the head tranny service tech dude, he opted to do a few things in the valve body to increase the line pressure, and firm up the shifts. I'm kind of interested to see how it does.
My '99 Regal GS did NOT do this ever. My GXP has 61k miles on it now.
I dont think GM fitted the axles right with the hub/ bearing.
