98 gtp transmission/shifting problems

cheezmunky · #1 06-24-2005, 11:37 PM

I have been having problems with my transmission lately. It has been shifting weird, revving up, shifting hard. It is weird. It seems to get worse as the car gets warmer. When I floor it, the car shakes in between first and second gears.
Just the other day I floored it from a roll and it seemed to go into neutral between first and second, no power for a second, and it then shifted hard into second and actually chirped the tires. Then it shifted fine into third.
Everything on my car is stock. I bought the car with 80,000 miles and it now has around 122,000 I have never changed the transmission fluid and I don't know if it had been changed prior to me owning the car. It seems the general consensus is not to flush the fluid although I read somewhere that flushing is bad but changing it is okay. What's the difference?
Would messing with the transmission fluid help anything at all or is it something different? Thanks in advance for any help.

troy1 · #2 06-24-2005, 11:58 PM

Flushing does not hurt your EPC electronic pressure control solenoid is probally bad in the trans is the SES light on?

BNaylor · #3 06-25-2005, 08:09 AM

I'm not in favor or against flushing depending on the circumstances but with 122K miles I'd be leary about a tranny flush. Bunch of horrors stories on that subject.

Probably won't hurt to change the fluid and filter first and go from there. You don't know how old it is.

After that get it to a good tranny shop for diagnostics and like the other poster suggested the PCS solenoid could be a likely candidate but with that mileage you're probably looking at a rebuild.

Thrasher CAI, DHP v1.0 ECU,
3.25 SC pulley, CAIT GMAF, Hi-Flow CAT,
u-bend delete, 160 TS, TB spacer,
MSD 8.5mm wires, Autolite 104 Spark Plugs,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials

kustomkid54 · #4 06-25-2005, 08:15 AM

DON'T FLUSH, just change. I agree.

Ripn12s · #5 06-25-2005, 10:34 AM

Sounds like a stuck valve body possibly. Thats why your getting hard shifts. The pressure is building up and then when the fluid finally clears the valve passage its at more pressure. Supposedly there was a problem w/ 98 valve bodies, atleast thats what i heard when doing my last trans rebuild

cheezmunky · #6 06-27-2005, 09:48 AM

well I changed the transmission fluid thi weekend. That helped with the hard shifting during normal conditions but it still shakes really bad when shifting from 1 to 2 while floored. I also decided to be stupid and do some reverse donuts (if only I had rwd) and now the power steering stops working every now and then. The level is okay but it has a brown tint to it. Does it need to be changed and if so how hard is it?

BNaylor · #7 06-27-2005, 10:08 AM

Quote:

Originally Posted by cheezmunky

well I changed the transmission fluid thi weekend. That helped with the hard shifting during normal conditions but it still shakes really bad when shifting from 1 to 2 while floored. I also decided to be stupid and do some reverse donuts (if only I had rwd) and now the power steering stops working every now and then. The level is okay but it has a brown tint to it. Does it need to be changed and if so how hard is it?

Check the condition of the serpentine drive belt and on the fluid change, I don't think its really a DIY job. You'll need to get all the fluid out of the lines and rack and pinion steering unit. Its important not to get any air into the system and have it purged because that could blow the rack & pinion seals. Could just be the power steering pump otherwise.

On the tranny shudder problem, its sounds like high line pressure possibly due to PCS solenoid/valve or valve body related. Is your torque convertor locking and unlocking correctly?

You've got nothing to lose at this point so try adding 10 oz. of "Lubegard" tranny additive. It may help free up the sticky valves if the tranny isn't yet a basket case. Good luck!

Thrasher CAI, DHP v1.0 PCM,
3.25 SC pulley, CAIT GMAF, Hi-Flow CAT,
u-bend delete, 160 TS, TB spacer,
MSD 8.5mm wires, Autolite 104 Spark Plugs,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials

cheezmunky · #8 06-27-2005, 03:08 PM

Is the serpentine belt the one that goes around the supercharger and alternator? I have been needing to replace it because it is worn out.

BNaylor · #9 06-27-2005, 03:33 PM

Quote:

Originally Posted by cheezmunky

Is the serpentine belt the one that goes around the supercharger and alternator? I have been needing to replace it because it is worn out.

Normally we call the one around the supercharger the SC drive belt. The serpentine drive is the main one that goes around the alternator, power steering pump, and water pump, etc. Its highy recommended to replace both if worn out. Most of us use the Goodyear Gatorback brand, especially on the SC.

Thrasher CAI, DHP v1.0 PCM,
3.25 SC pulley, CAIT GMAF, Hi-Flow CAT,
u-bend delete, 160 TS, TB spacer,
MSD 8.5mm wires, Autolite 104 Spark Plugs,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials

kustomkid54 · #10 06-27-2005, 05:14 PM

Quote:

Originally Posted by bnaylor3400

Normally we call the one around the supercharger the SC drive belt. The serpentine drive is the main one that goes around the alternator, power steering pump, and water pump, etc. Its highy recommended to replace both if worn out. Most of us use the Goodyear Gatorback brand, especially on the SC.

Thrasher CAI, DHP v1.0 PCM,
3.25 SC pulley, CAIT GMAF, Hi-Flow CAT,
u-bend delete, 160 TS, TB spacer,
MSD 8.5mm wires, Autolite 104 Spark Plugs,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials

Will this make it easier?

cheezmunky · #11 06-28-2005, 07:57 AM

yeah I bought both belts alst night because they are both in bad shape and I will replace them tonight. I have found that it only quits when idling so that leads me to believe it must be the pump or the belt isn't catching.

I have my car's trans scheduled to be looked at on the 11 (small town, one trans shop, off for the 4th next week, don't ask) but hopefully he can get a code to see what's going on

cheezmunky · #12 07-21-2005, 08:02 AM

Finally got the car to a shop. The guy told me the transmission needed an overhaul and he wouldn't know what exactly was wrong until he took it apart. Price? Somewhere between $1500 & $2200. Then I reallized I had an extend warranty on the car, took it to the dealer and they told me it needs a new pc solenoid (good job troy and bnaylor) and a new power steering pump, which I already knew. All I have to pay now is $23 for the fluids they replace. Thanks for all the input.

dmasjz45 · #13 07-21-2005, 05:29 PM

Quote:

Originally Posted by cheezmunky

Finally got the car to a shop. The guy told me the transmission needed an overhaul and he wouldn't know what exactly was wrong until he took it apart. Price? Somewhere between $1500 & $2200. Then I reallized I had an extend warranty on the car, took it to the dealer and they told me it needs a new pc solenoid (good job troy and bnaylor) and a new power steering pump, which I already knew. All I have to pay now is $23 for the fluids they replace. Thanks for all the input.

probably could have spared your power steering if you didnt beat on it doing donuts

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