GTP Tranny Problems Symptoms??

[McCoyH]

Hey guys, i've had a few GTs over the years and just got my first GTP today. I got it very cheap as the previous owner thinks the tranny is starting to go out. I work at a car lot (doing detail and tint) and the mechanic on the lot told me he thinks its just a Idle Control Sensor (or something of the sort, I'm not a mechanic...)

I haven't had enough time to drive it yet to give you all a descriptive idea of what the "tranny is doing" but here are a few things I HAVE noticed:

1. Tranny stayed in first gear while attempting to test drive down the highway (4k RPMs)the first couple mins, then shifted fine afterwards.
2. Idle jumps all over (RPMs) while sitting at stop sign or in park
3. Tranny occasionally shifts hard, has a slight slipping feeling (hardly noticeable), And/or has slight hesitation between gears, usually between 1st and 2nd.
4. Car is lacking power (not saying the supercharger is bad, though it could be, just saying that it feels like it needs plugs/wires real bad or is maybe lacking fuel or air.

With those 4 things said (that's all ive noticed so far) what would be your best guess?

Thanks a bunch for any help! And I look forward to participating in the community as I'm sure I'll have lots of questions... ha



EDIT: Another side note, it shifts pretty good 75% of the time, it's just once in a while I'll notice something that catches my attention. But the idle issue is constant.

[FordMan77]

I would say clean the MAF, and then check for vac leaks. The T under the S/C snout likes to rot out and cause this. Spray carb cleaner around all the vac. connections and see if the motor smooths out. If so, there's a leak. The MAF can cause trans shifting issues.

Probabaly would also do a tune-up (plugs,wires, fuel and air filters).

Pull the dipstick for the trans and note the color and smell of the fluid. Is it nice and red or brown/black and smell burnt? May be time for a pan drop and fluid/filter change. And no, don't flush the trans.

Get the car scanned for codes. Even if the CEL isn't on there may be transmission codes present, as they don't always set a CEL.

[McCoyH]

Well i did some poking around and also hooked the scanner up to the car and found out that the tranny that it has in it isnt even the right tranny for the car.. tisk tisk precious owner... so i have another gtp tranny ordered and hopefully thatll fix that problem if not ill follow your advice. Thanks

[FordMan77]

Let me guess, they put a GT trans in it and didn't correct for the gear ratio.

[McCoyH]

Correct you are sir.
I ordered a used tranny off car-part.com...
Is it a bad idea to put a used tranny in?
Someone here at the shop told me if I put a used one in, it'll just go out in a couple months...

[Scottydoggs]

having your pcm tuned for the gears you have in the car now is a lot easier. and cheaper i would have to say.

[dsmuts]

yeah just tune your pcm for the gears and enjoy.

[McCoyH]

And how do I go about tuning my PCM? Can I do it myself at the shop or do I have to have a tuning shop do it?

[dsmuts]

you can do it yourself if you buy dhp or hp tuners.

[McCoyH]

I think I'll fee better just replacing the trans since previous owner prolly drove the car with this tranny in it for a while... its prolly destroyed

[FordMan77]

Correct you are sir.
I ordered a used tranny off car-part.com...
Is it a bad idea to put a used tranny in?
Someone here at the shop told me if I put a used one in, it'll just go out in a couple months...

As long as the used tranny was maintained, then no. I'm rocking a used one out of a 98 that a guy was parting out. So far, so good. Just be sure to drop the pan and change the fluid/filter and DON'T flush it. Matter of fact, since the TC will be accessable I would drain that too so you can be sure that you have 98% new fluid in there. The only thing I wish I had done while mine was out was change the TCC solenoid as I get a bit of RPM bounce under a load in lockup.

[Scottydoggs]

if you dump the converter, well wont that almost be a full flush, it holds like 7 or 8 quarts right?

id leave the converter on. pan drop, filter, see whats in the pan, hopefully nothing, and toss it in the car.

doing the tcc and pcs is would be a good idea, they dont cost all that much, and its easy when the trans is out of the car to do.