"Rev and Clunk" Issue ? 08 5.3L GXP

**radjjak21** · 02-24-2016

Hello
I have a 2008 Pontiac Grand Prix GXP 5.3L v8. with the 4T65E-HD 123,000 miles
randomly when i am at a stop and i go to hit the gas my RPMs rev up and the car doesnt move then it drops/clunks into first.. Any ideas why? seems to shift smoothly, Some time rpms flair back in forth between overdrive.. going around 50 mph.. I have the TransGo shift kit (only the springs, parts that could be accessed from below tranny) installed on it.. Fluid and filter change more then 4 times.. along with a new magnet for pan...
Thanks

**J57ltr** · 02-24-2016

This is covered in the tech tips, but as I recall it's the apply piston seal not sealing all the way and as you rev to take off the seal has more pressure behind it and it pops in and grabs and goes. My car does the same thing at times. I raised the trans pressure and that seems to help, I haven't had it happen since, but it only did it once in a while anyway. The fix from what I read was a rebuild.

Jeff

**radjjak21** · 02-24-2016

How were you able to raise the pressure?

**Scottydoggs** · 02-24-2016

ancient Chinese secret ..........

you need a tuner to do it.

**BrandonHall10** · 02-24-2016

Originally Posted by J57ltr

as I recall it's the apply piston seal not sealing all the way...The fix from what I read was a rebuild.

Looks something like this:

**ADrugDealer** · 02-24-2016

Like stated above apply piston. Rebuild time!

**radjjak21** · 02-24-2016

Sigh

**J57ltr** · 02-24-2016

how often does it do it?

**ADrugDealer** · 02-24-2016

Order a master rebuild kit, valve body, channel plate and whatever else TEP tells you do and DIY it. Or just buy one from TEP.

TEP = Triple Edge Performance

**robinsone** · 02-24-2016

What level of DIYer do you need to be to tackle this tranny rebuild. I've done a lot to a motor and car short of a head gasket install. Is this something a novice can do. It would appear you need to drop the subframe from the body, so that's nothing a person can do in their garage is it. Is there an easy way to get access to the tranny in order to do an effective rebuild short of pulling the motor and trans. Any tricks to pull this off in a garage.

**BrandonHall10** · 02-24-2016

Transmission removal and install can be done with common hand tools and a little lumber. Air tools help.

The thing that puts a garage rebuild out of reach for most is the specialty tools.

**robinsone** · 02-24-2016

The only thread I've seen that does a trans removal is this one.

http://www.grandprixforums.net/threa...a-transmission

Do you need a engine hoist at all or some type of trans jack stand as you just need enough space to remove the case cover to do everything, but I could be wrong.

**ADrugDealer** · 02-24-2016

Are you talking rebuild as in you doing the transmission internals?

**radjjak21** · 02-25-2016

It only does it off and on maybe twice a month driving it daily, I notice when it does it once it does it a hundred times tell I shut the car off and turn it back on then it comes out of it... I'm sure I could rebuild it my self, just don't have the time or energy to do it.. And don't have the money to pay for someone to do it... Best option for me sadly is to try and trade it in in a few months... �� What causes these transmissions to **** the bed so often ? I drove this thing with a light foot and never beated on it and kept fluid clean... To much motor for tranny ? Displacment on demand ?

**J57ltr** · 02-25-2016

Mine does that about as often but it will usually only do it a couple of times. The first time it happens, I start off slower and most of the time I will feel it engage then it's good to go. After a couple of those it seems to be fine. I noticed it happen last summer so I don't know how long it will last, I figure if I am easy on it when I initially take off then it won't really get worse but I would like to hear from others. I plan on getting a new transmission soon just to rebuild I haven't found one in the yard yet.

Jeff

**robinsone** · 02-25-2016

This is starting to sound like a PCS issue.

http://www.tripleedgeperformance.com...ift-P1811.html

So I have 206k on my engine and trans. I started getting hard shifts all the time around 145k and the only remedy was turning off the engine, waiting for a few seconds and then turning it back on. If this is the case for you then a shift kit could help.

http://www.grandprixforums.net/threa...ailed-Pictures

I personally did a shift kit and a trans cooler just to see how many more miles I could go without a rebuild.

No I get a delayed engagement on occasion, but this happens only when I'm at a dead stop and go to hit the gas I get a delayed or bump stop some people say. This does not happen every time or with every shift though, only on occasion. Maybe once a week if that, but at least 2-3 times a month I guess. There is a lot of information available.

http://ls1tech.com/forums/ls4-perfor...ement-fix.html

http://www.grandprixforums.net/threa...e-or-Shift-Kit

http://www.grandprixforums.net/threa...D-Transmission

If it were me, try the shift kit. You can get them for less than $50 nowadays and they are easy to install. If you can't afford something new or the rebuild, this might be your best option to keep it running for as long as you can.

**ADrugDealer** · 02-25-2016

You can try the cheap spacer shift kit. Just drop some spacers in the accumulator. Cost like 50 cents for the spacers. Just need a new filter, 2 gaskets for the pan and accumulator and some fluid

**ADrugDealer** · 02-25-2016

http://www.clubgp.com/newforum/tm.as...212586#2284831

**J57ltr** · 02-25-2016

My car has a shift kit installed and 20% higher pressure and a stand alone cooler still does it. It normally seems to do it when the trans is cold though. Now that I have an external trans cooler it takes a long time to warm up. It seems a rebuild is the only solution. It costs roughly $100 to install a shift kit, but can't hurt. It's not anything like a shift kit for a RWD car that's for sure.

Jeff