Transmission Issue. Need help!!!

thatsnninety5

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I have 98’ GT (4.6) with the 4 speed automatic trans w/ od (4r70w). So just recently of about a month ago maybe 20 days I put a new trans wire harness in because the old one burnt up. Ive made a post on this forum about it in the past. But here is my issue, so before the old harness burnt up I had no slippage, gear caught like butter, no issues whatsoever, until the harness burnt up, I repaired the harness with new wiring, solder, heat shrink etc. It worked fine until it had burnt up again which lead me to putting this new harness on. Now recently of yesterday I get in my car to drive it and near my house in a hill that i have to go up. I put the car in D and on flat ground and down hill it work completely fine. As soon as I hit that stop sign and make that right to go up the hill the car just acts like its in neutral. Itll rev up to about 5k and catch the gear and come down to 2k and make me move forward about 2 feet, it will keep doing this until i get to the top of the hill, unless I hold the break as this happens I drift backwards and lose my progress. About 20 minutes ago I was leaving my girlfriends house, sat outside with my car sitting in D and its not even moving, mind you this is a flat even ground. So I reversed out of her neighborhood and got to a hill I could coast down. I got to the bottom of the hill where the ground was flat and I hit the gas and it revved up 5k again and it caught went down to 2k until it shifted to second and it started to kinda go. But once I get going all this stops until I come to my enemy, a full stop with a hill ahead of me. My check engine light is on but only for System too lean bank 2. I have no idea what the issue could be. any pointers? Is my tranny just gone?
 
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thatsnninety5

thatsnninety5

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I have 98’ GT (4.6) with the 4 speed automatic trans w/ od (4r70w). So just recently of about a month ago maybe 20 days I put a new trans wire harness in because the old one burnt up. Ive made a post on this forum about it in the past. But here is my issue, so before the old harness burnt up I had no slippage, gear caught like butter, no issues whatsoever, until the harness burnt up, I repaired the harness with new wiring, solder, heat shrink etc. It worked fine until it had burnt up again which lead me to putting this new harness on. Now recently of yesterday I get in my car to drive it and near my house in a hill that i have to go up. I put the car in D and on flat ground and down hill it work completely fine. As soon as I hit that stop sign and make that right to go up the hill the car just acts like its in neutral. Itll rev up to about 5k and catch the gear and come down to 2k and make me move forward about 2 feet, it will keep doing this until i get to the top of the hill, unless I hold the break as this happens I drift backwards and lose my progress. About 20 minutes ago I was leaving my girlfriends house, sat outside with my car sitting in D and its not even moving, mind you this is a flat even ground. So I reversed out of her neighborhood and got to a hill I could coast down. I got to the bottom of the hill where the ground was flat and I hit the gas and it revved up 5k again and it caught went down to 2k until it shifted to second and it started to kinda go. But once I get going all this stops until I come to my enemy, a full stop with a hill ahead of me. My check engine light is on but only for System too lean bank 2. I have no idea what the issue could be. any pointers? Is my tranny just gone?
Another code im pulling is p1131 which on my reader just say “manufacturer control” and the other one for the system too lean bank 1 is p0171
 

lwarrior1016

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Have you checked the transmission fluid level and condition?

It should be checked when the car is warm and idling in park. Fluid should red and full.
 
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thatsnninety5

thatsnninety5

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Have you checked the transmission fluid level and condition?

It should be checked when the car is warm and idling in park. Fluid should red and full.
I have checked it and everything is good. I recently just did a trans flush and put new trans fluid in, about 4 months ago.
 

lwarrior1016

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I would like to see a scanner hooked up to it, to see if it is commanding the next gear, or what gear it thinks the shifter is in.

I don’t know for sure in this transmission, but I know in some others, if the MLPS (neutral safety switch on the side) doesn’t read correctly it could get confused on what gear you want.

I hate to say, you may have to get it to a transmission shop for diagnosis.

Also, what was going on for it to burn wires?
 
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thatsnninety5

thatsnninety5

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So it was burning wires because the exhaust fell of at the headers, I have BBK Shorty headers, and the heat from the headers burnt it up. I work at a jiffy lube that has those high tech scanners that can read absolutely anything, so could I use that instead of going to a trans shops? When you say it could be the MLPS, I think it could be because when I put it in drive I usually feel it go into gear and my RPMS go down but it doesnt really do that. But if I put it in reverse it catches fine and I press the gas and it reverses like nothing is wrong.
 

lwarrior1016

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So it was burning wires because the exhaust fell of at the headers, I have BBK Shorty headers, and the heat from the headers burnt it up. I work at a jiffy lube that has those high tech scanners that can read absolutely anything, so could I use that instead of going to a trans shops? When you say it could be the MLPS, I think it could be because when I put it in drive I usually feel it go into gear and my RPMS go down but it doesnt really do that. But if I put it in reverse it catches fine and I press the gas and it reverses like nothing is wrong.
Yes, you could see all the needed information. The concerning part is, that sounds like a fluid pressure issue. You could have a bad pressure control solenoid, or you could have clutches that are burnt up and not applying. The forward clutches burn up very quickly.
 

lwarrior1016

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That’s another thing too, the forward drum likes to blow the snap ring off, and that sometimes makes forward gears almost impossible to engage.
 
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thatsnninety5

thatsnninety5

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Yes, you could see all the needed information. The concerning part is, that sounds like a fluid pressure issue. You could have a bad pressure control solenoid, or you could have clutches that are burnt up and not applying. The forward clutches burn up very quickly.
Where is the pressure control solenoid located? Could I replace it myself in my garage with the car on ramps/jack stands. If it is the issue of course. And with a snap ring or the clutches being burnt, would that mean id need my trans rebuilt or get a new trans? Which is more expensive to do?
 
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thatsnninety5

thatsnninety5

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That’s another thing too, the forward drum likes to blow the snap ring off, and that sometimes makes forward gears almost impossible to engage.
So I just took my car on the highway and it was pretty good but it wont shift to 3rd. Wont even attempt. All I have is 1st and 2nd
 

lwarrior1016

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You could get that one rebuilt, or sometimes the shop will swap it with another one. I think it’s all about the same price. I will say, find a reputable shop to do it. And let them build/acquire the transmission. If you buy one and have them swap it, there is no warranty and if something happens, you’ll pay them to do it twice.
 
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thatsnninety5

thatsnninety5

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You could get that one rebuilt, or sometimes the shop will swap it with another one. I think it’s all about the same price. I will say, find a reputable shop to do it. And let them build/acquire the transmission. If you buy one and have them swap it, there is no warranty and if something happens, you’ll pay them to do it twice.
Okay, I shall look into it. Im going to add some Lucas Slip Stop tranny stuff you can get at an auto parts store and see what happens. But where is the pressure sensor solenoid located at?
 

lwarrior1016

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Okay, I shall look into it. Im going to add some Lucas Slip Stop tranny stuff you can get at an auto parts store and see what happens. But where is the pressure sensor solenoid located at?
Please don’t add that. It won’t help anything and could potentially make it worse.

Sorry, I missed the question before. The pressure control solenoid installed inside the pan. I think you have to drop the valve body to change it.
 
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thatsnninety5

thatsnninety5

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Please don’t add that. It won’t help anything and could potentially make it worse.

Sorry, I missed the question before. The pressure control solenoid installed inside the pan. I think you have to drop the valve body to change it.
Okay I wont add that then. Im going to send my car to a trans shop for service and see what they have to say about it as well. I will keep you posted
 

lwarrior1016

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Okay I wont add that then. Im going to send my car to a trans shop for service and see what they have to say about it as well. I will keep you posted
That’s probably a good idea, even though I hate to say it. Transmission problems are difficult to diagnose without being there in the car.
 
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thatsnninety5

thatsnninety5

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That’s probably a good idea, even though I hate to say it. Transmission problems are difficult to diagnose without being there in the car.
I planned on dropping off the whole car anyways so they can attempt to drive it and diagnose it to see the issue
 

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Yea that lucas oil crap may help somewhere in somethings but not in my vehicles. I truly believe that crap hardens seals.
 

lwarrior1016

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Yea that lucas oil crap may help somewhere in somethings but not in my vehicles. I truly believe that crap hardens seals.
From what I’ve experienced, it makes the seals real gummy. That might make them hold for a bit but then they deteriorate and get bits of rubber everywhere, even in the valve body. I took apart one that I almost couldn’t get the pistons out of because there was so much rubber built up in between the housing and the piston.
 

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