Turn Up Line Pressure or Shift Kit???

**GXPerforms** · 05-05-2015

My 2006 Grand Prix GXP with 119,000 miles has since I've owned it has had an occasional delayed engagement (taking off from a stop and banging into gear after revving) and sloppy shift problem (sometimes it'll shift painfully slowly). These problems are so intermittent. Some days the transmission shifts good and runs great and then other days it's just not feeling it. I don't think this transmission needs rebuilt yet, as it has its days where its a beast and when I changed the fluid I didn't find any signs of excessive wear.

I've read online and found two things that people do that usually solve these issues. I would like to know which is the better route to help solve these issues:

1. Crank line pressure up some via tuning

or

2. Install a shift kit.

Which one should I take on and that you think would help solve some of these occasional issues?

Shift kit's definitely cheaper hhaa

**Booba5185** · 05-05-2015

Both. and a cooler.

**GXPerforms** · 05-05-2015

Right now I only have the resources and time to mess with one or the other. Which one will make the biggest difference? And if I should do a shift kit, which shift kit do you recommend to help solve this?

**Booba5185** · 05-05-2015

Transgo shift kit, and a bottle of Lubeguard Red. Then goto the JY and pick up a transmission cooler from a Explorer. They're more than enough to cool our transmissions (within reason), have mounting ears, and are pretty cheap. Make sure to clean it out. Ebay has the shift kit for about $40, so it'll help in the wallet department.

**GXPerforms** · 05-05-2015

If it is a shift kit I should go with, I'm leaning towards doing a ZZP kit, because I like that you can select shift firmness (I would probably be going with the hardest setting

). I've heard good things about TransGo, but I'm not sure if that kit would help alleviate these issues, since I heard its not a whole lot over stock.

**Booba5185** · 05-05-2015

Zzp is the worst shift kit available. If you want a selectable firmness type thing, I hear good things about Intense. Transgo really is the best though.

There's always the DIY route where you order spacers from McMaster and put the in. The ZZP kit is just plastic spacers and you just put in a longer spacer for firmer shifts. Transgo has an entirely new spring set to put in. If Transgo doesn't fix your problem, no shift kit will.

**GXPerforms** · 05-05-2015

Will the TransGo help with the issues I'm having? I read somewhere that it's almost just a stock replacement. And I've heard reallllyy bad things about Intense screwing over people.

**02NavyBlue** · 05-05-2015

Stock GT/GTP if it matters

Transgo

A shift kit will help the slow shifts, but not the bump start. Higher line pressure would cover that problem up for a while.

**Booba5185** · 05-05-2015

I edited my previous post...Transgo is nowhere near a stock replacement.

**GXPerforms** · 05-05-2015

Originally Posted by 02NavyBlue

A shift kit will help the slow shifts, but not the bump start. Higher line pressure would cover that problem up for a while.

I'm thinking I'll go with the tune then and do higher line pressure. I know that when driving in TAPShift mode, line pressure is increased - and when driving in TAPShift mode, I almost never have shifting problems. This is why I usually drive in TAPShift and why I think increasing line pressure would actually help.

**Booba5185** · 05-05-2015

It'll be a band-aid fix. The transmission itself needs work. Might just be a fluid flush (which you have to do when you install a shift kit), or it could be something a bit more involved.

**GXPerforms** · 05-05-2015

Would the Diablosport tuner increase line pressure enough? Or would I have to step up to something more steep (and much more expensive) like an HP Tuners?

**GXPerforms** · 05-05-2015

Originally Posted by Booba5185

It'll be a band-aid fix. The transmission itself needs work. Might just be a fluid flush (which you have to do when you install a shift kit), or it could be something a bit more involved.

I changed the fluid already, didn't help and didn't hurt. I also got rid of the fridge magnet and installed the upgraded magnet and another upgraded magnet on the filter.

**Booba5185** · 05-05-2015

You'll want an actual tune, not a POS OBD2 port wannabe. HPT gives you the ability to tune. I'd contact Overkill for a tune, or maybe wait a week or 2, since Reptile is "researching" 04+ tunes. Reptile is a member of the site and has fantastic tunes, I have one on my 2000, but he doesn't do 04+'s yet.

What temperature is your transmission running at?

**GXPerforms** · 05-05-2015

It rarely runs over 204*F and its rare to see it above 200*F. Usually around 150-195*F.

**Booba5185** · 05-05-2015

195*F is okay, but I'm not comfortable with mine running that hot. 175*F is the max "optimal" temperature. That's not your problem though.

**GXPerforms** · 05-05-2015

Any idea what causes these issues? Bad PCS? This seems to be an extremely common problem with these trannys.

**GXPerforms** · 05-05-2015

It mainly reaches those higher temps when sitting in traffic or on hot days... like today.

**Booba5185** · 05-05-2015

It can be the PCS, among other things. Do you have any means to pull codes? With transmission codes you have to pull codes when the problem happens (or at least don't shut the car off before reading codes).

**Booba5185** · 05-05-2015

It's possible it's your forward apply band, too. When you put it in manual 1st it applies another band, and that's why it doesn't slip. I'm not 100% sure that Tap Shift applies that manual 1st band, but I think it does.