Mechanics

TRANSMISSION PROBLEM?

2000 Pontiac Grand Prix • 158,644 miles

Ok, so I will explain this the best I can, I am a good mechanic but havn't had the privelage of being able to diagnose or work on a transmission, usually I can fix anything as long as I know what it is and where it is. Ok here is the problem, when flooring the car it catches at 3500 to 4000 rpm and bumps back and forth then catches. I can sorta understand this, but what I dont understand is when u let off the gas the rpms are supposed to gradually decline and help decrease the speed of your vehicle, this doesn't, it acts like a mqnual and drops to 1000 rpms to 700 rpms. Confuses me, some minor slipping too. Please help as I am trying to make this a stable ride to my soon to be born child.
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Cjelswick87
July 3, 2013.




I'm assuming that you already have, but check the transmission fluid level and also look at the color of the fluid (supposed to be red).

Is the check engin elight on?

How does it fell as it shifts through the gears?
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Freemba
Jul 3, 2013.
It is not a rough shift, and thw tranny fluid looks normal, goes through the gears just fine as long as I drive it like an old man, what worries me is the lack of drag when u let off the gas, it just drops to 1k rpm, and no check engine light, any ideas?

Tiny
Cjelswick87
Jul 3, 2013.
Oh to add, when I push back down on the gas it revs back to the rpms required to maintain the current speed

Tiny
Cjelswick87
Jul 3, 2013.
Does the transmission have to upshift after you've let off the gas, coast for a while and then reapply to gas?

You may have to have the pressure read at a transmission shop. It kind of sounds like once you let off the gas it disengaged, yet doesn't downshift.

Freemba
Jul 4, 2013.
I rechecked the fluid, it was brown, and no, doesnt shift to lower gears, just idles and reengages when I apply the pedal

Tiny
Cjelswick87
Jul 4, 2013.
What does getting my pressure checked mean? And what happens if it is bad? You have been real helpful by the way, thank you so much

Tiny
Cjelswick87
Jul 4, 2013.
Please excuse the fact that I didn't explain "checking the trasmissions' pressure" when I first mentioned it.

The automatic transmission, in some cases shifts by using hydraulic pressure (pressure built by its hydraulic pump), and in all cases these transmissions use this hydraulic pressure to push its clutches together, providing enough friction to keep them togehter as they spin inside of the transmission. This in turn, turns a shaft which eventually leads to turning the drive axles of the vehicle, causing it to move under its own power.
As the transmission shifts, each gear requires a certain amount of pressure in order to operate properly (the pressure required is usually different for each gear).

By checking the fluids' hydraulic pressure the technician can determine if the clutches inside of the transmission are capable of providing enough friction to move the vehicle properly (without slipping or other shifting problems).
Once this is determined they can then make an informed decision on the best repair for your problem.

Also, if the fluid is brown, instead of red, this means that the friction material from the clutches is falling off. This material gets into the fluid and changes its color; which is a indication that the clutches are wearing out (which greatly reduces their ability to produce enough friction to shift the transmission properly).

Often a last effort (before having the transmission overhauled) is to change the transmission fluid and filter; to see if that remedies the problem. If so, you've saved a lot of money. If not, you haven't lost a lot of money (at least that used to be the case, but have you seen the cost of automatic transmission fluid lately?).

Call around to some of the transmission shops in your area, there may be one which will check you transmission for FREE (they willsometimes do free inspections to drum-up business). However, don't buy anything until you're told me what the results are. There may be a more economical way to handle this than a complete overhaul.

Freemba
Jul 4, 2013.
Will do, ill call around tomorrow, hopefully those "pieces" falling off aren't too expensive, I am not against changing one out

Tiny
Cjelswick87
Jul 5, 2013.

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