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2000 GTP 1st gear slip/bang issue

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Progas

New member
I have a 2000 GTP and if I manually shift it down to first then take off, it acts like it is slips then bangs a bit into gear and then goes fine. This will happen even when taking off easy from the light. If leave the trans in D or 3 then it works fine, even if I hard launch the car and spin the tires. I am thinking it could be somewhere in the valve body but I don't really have much experience with these transmissions. I know there is a pressure control solenoid problem with some of these transmissions, but Im not sure if it cause this symptom. I dont want to have to replace it if I dont need to, they are a pita to get to, and Im sure a trans shop would cost half and arm and maybe some leg.

Anyone ever seen this problem, or point me in the right direction?
 


Before your problem WHY are you putting the shifter in manual 1 or did you word that backwards? Generally there are a handful of worn internal parts that cause a slippage or no fwd movement in D or 3 but will take off fine in manual 1. There is no reason to manually shift these transmissions and is hard on them if you keep doing it and you are going to cause damage if a lot of heavy throttle driving in this range. In manual 1st and 2nd there is much higher line pressure and this generally overcomes problems that you can experience in D or 3. To have slippage in just manual 1 but not in D seems really odd. Is the fluid level up the the full line with the car warmed up-running- and in park? Without a pressure gauge and a scan tool to command line pressure it may be difficult to track your problem.
 
This is my first GTP, I have not had it long, I build prostreet type vehicles. I am used to manually shifting down to first, for dead stop or float launches, and then manually run through the gears, I build a nasty TH350.

The more I read I see that these cars are so computer controlled that it is best to just let the car do the shifting.

I will not ever manually shift car again, now that I understand how it works, but it still worries me that there could be unseen problems.

The slipping and then banging into pulling if it is ever in 1st manually from a dead stop does have me concerned. If the car is up running at say 10mph and you down shift manually to 1st let the revs come up easy it will wind up S/C and then, well.... if you tromp it, it goes fine, and really fine, I must say. I have built carbed hot V6's, but these cars, just are impressive. Alot to be gained I see very simply.

Anyway if you leave the car in D or 3 and tromp it at dead stop, or at 15mph float it will just cut loose with some FWD posi, and not a problem noticed. I know your first response will be don't manually shift it, and not problem. I agree with you, and will let it do its thing, but any thoughts on the problem? Is it something to be worried about immediately?


Oh and yes the fluid level is full it actually looks like it is maybe about 1/2qt over full. The fluid is red, and very clean, no burned smell. I am going to do a filter replacement this weekend with the oil change, and will inspect the pan for excess clutch wear, and or metal. I have had the car, only long enough be doing the first oil change since I bought it.
 
Yep these transmissions are 100% computer controlled and it is best to let the computer do its job and do all the shifting. Your problem is odd and without a pressure gauge on the trans it is hard to say what direction to look at.
 
Thanks Trannyman

I appreciate your input. I cant check the pressure without buying guages, I will however have a scan tool soon, its my next buy, so if there is a hidden code not showing I will find it hopefully.

I am by the seat of my pants thinking that this tranny will be fine for a while, till I get my HP tuner. When I blow the tranny I have already found replacement/rebuildable's at around 500 bux. So I'm thinkin I will buy one and rebuilt it, and keep it waiting in the wings for when mine goes bad. I have read the posts about the last rebuild you helped with online and I will be hounding you as well for valving, and tricks, but I will post every pic as I go just to help out my bro's trannys are not that hard.

Everyday I see how bad ass these cars are, I run about 140mi to work and back each day. I ran a twin turbo SAB my buddy, the other day, and he couldn't believe how I could go from 60 to 118mph so fast. He gave me a grin in my review.
 
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