Thread: help, newby with 07 Gxp mods and order to apply?

I'll probably just do a pan drop then. Out of curiosity, why would a flush hurt though?

never flush a tranny if you dont know its service history. truth is most dont service them at all.

service should be done by 60,000 a flush is fine if the tranny is working and the fluid looks good still. or sooner if you live in a hill fulled area or real hot temps outside.

i got my last gmc truck new. i flushed it every 30,000 miles. aka every year in my case lol


what happens is theres clutch material held in the fluid its helping the clutches work. take all the old fluid out and the old clutch material and your car can stop moving asap. seen it happen.

safe thing to do is a pan drop and 8 new quarts of tranny fluid with a filter, add a shift kit while the pan is off. they also help keep the trans living longer ( if your not beating the crap out of it daily) being your in Fl you may want to add a trans cooler too if your trans temps are over 200.

heres a shift kit how to. it covers the pan drop as well and everything you need http://www.grandprixforums.net/threa...ailed-Pictures

Originally Posted by spacerabbit69

I have right under 115k miles BTW

just a pan drop for you for sure then

Originally Posted by eighty3bordeaux

I recently bought a 08' GXP, and I'm doing a complete trans flush this week. My car only has 50K miles on it.

make sure your fluid is still RED and not burnt smelling those v8's tear up these trannys. if the fluid is dark or burnt smelling do not flush it. just do a pan drop and filter change.

Depends if you want to spend money or not, flipping takes like 5 min and is free. But poly is way more solid, might fell vibration at idle with poly.

Sent from the Milky Way

Im not sure if GXP lower mounts are the same as 3800 mounts or not but if they are check to see if are leaky and broken looking then replace with solid mounts or new regular ones.

Sent from the Milky Way

Change plugs and wires if its over 100k...just put factory wires and plugs in..it will livin up the car for sure if they hsve.t been replaced yet.

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Originally Posted by timboku

Change plugs and wires if its over 100k...just put factory wires and plugs in..it will livin up the car for sure if they hsve.t been replaced yet.

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Negative- you'll want to replace plugs and wires a lot sooner than 100k..especially the LS4 do not get factory woresets nor plugs either NGK tr55' or tr6. Msd wires

Originally Posted by spacerabbit69

http://intense-racing.com/PROD/LS4-PRO-UMMP.html
These are the right ones for an 07 gxp?

Which is the better manifold, ls6, im guessing? Im gonna get headers, which ones are best, and do i still need a downpipe if i get headers?

Also, what about maf sensors?

Obx have turned out good. Doug thorleys are good too there ceramic coated. Also the ls6/2 are good manifolds ad well.

Originally Posted by spacerabbit69

Ive been told to get poly mounts. One guy has square and round. I thought it was one or the other? Is this just the mount by the radiator they are talking about? If it is one or the other which ones are better?

Squares are for the mount closes to the radiator.. The circles are for the dogbones.

Generally the squares make way more of a difference. The dogbones circles well many of us leave those alone and stick with the stock rubber ones. Some guys complain of the vibration with them, others aren't bother by it. My suggestion try the squares first then go from there.