89 GP Tranny issues, need a techie
Necrobater
04-05-2007, 08:55 PM
Hi guys, I'm new here, but have been working on autos since I was about 12. I've done engine swaps, tranny swaps and so on, with no issues. This has got me worried.
My 89 pontiac grand prix's overdrive has been out since I got the car. Car had 160,000 when I got it and now has about 225,000. I know its the overdrive and not the TCC because the voltage to the proper pin for the TCC becomes present when it "shifts" last. Well I drove it like that for about a year with of course money fall out of my butt for gas. About a month ago, it started a "rubbing" sound only when it was in any gear and not moving, and would gradually go away when The car started moving. Now I know this is caused by needle bearings going bad in the Torque Convertor. Well incidentaly I had purchased an almost identical car, an LE instead of a standard version. It only had 132,000 miles on it and ran fine except the owner ran it with no poil pressure for about a month, so the engine was SHOT. The tranny ran fine when parked, all gears shifted, no problems at all. Well it was sitting for about 2 years and I decided to swap the tranny and TC into my car to fix the TC issue and the lack of an overdrive. I was concerned that sitting that long could cause seals to dryout and so on. I replaced the TC pump seal and axle seals. I put the tranny on its side to soak it with tranny fluid (internally) before I ran it. I also spun the pump shaft slowly for about 5 minutes to get fluid moving before the install. I did this to help prevent any seals from being ripped apart from being dry.
Well It seemed to run fine. But after about 10 minutes it does not always want to go into gear. The tranny is a 4T60. I've had the old one apart to slavage the aluminum out of it. Learned quite a bit about the layout and how it functions, but I'm far from an expert. My concern is what is the mechanics, that causes it to go into gear?
There is a few reason I think this could be happening. One of the "cylinder" valves is sticking. Or possibly a vane is sticking on the pump which would decrease pressure and not cause it to go into gear (if thats how it does it). I've changed the fluid and filter once. Also put lucas tranny treatment in it. I know the tranny isnt controlled electronically to go into gear because I unhooked the harness when it was going into gear good, and it still did. From what I seen when I had the old one apart, There is one solenoid presumably for the TCC, and 3 "pressure sensors." Maybe I'm misunderstanding these, but why have these pressure sensors if there are no shift solenoids that I can see. The haynes manual shoes 2 shift solenoids for 1-2 and 2-3.
The haynes manual of course is of no help. Should I run it more and see if it gets better?
Also since the swap, my oil pressure gauage is reading about 30 psi low. I know its wrong because I've hooked a manual gauage up to it. I need to recheck the wiring harness, but I already have, but going over SERVERE bumps causes it to go back up for a bit.
This move to inprove fuel economy and fixing impending doom from the TC has left me with an unreliable car. Sucks stopping at a stoplight not knowing if its going to stay in gear. BTW, it never drops out of gear when moving. It also shifts perfectly with no hesitation. I've also ran it downhill when it wouldn't go into gear to see if I could bypass first and it did go into second gear.
Any advice would be appreciated.
My 89 pontiac grand prix's overdrive has been out since I got the car. Car had 160,000 when I got it and now has about 225,000. I know its the overdrive and not the TCC because the voltage to the proper pin for the TCC becomes present when it "shifts" last. Well I drove it like that for about a year with of course money fall out of my butt for gas. About a month ago, it started a "rubbing" sound only when it was in any gear and not moving, and would gradually go away when The car started moving. Now I know this is caused by needle bearings going bad in the Torque Convertor. Well incidentaly I had purchased an almost identical car, an LE instead of a standard version. It only had 132,000 miles on it and ran fine except the owner ran it with no poil pressure for about a month, so the engine was SHOT. The tranny ran fine when parked, all gears shifted, no problems at all. Well it was sitting for about 2 years and I decided to swap the tranny and TC into my car to fix the TC issue and the lack of an overdrive. I was concerned that sitting that long could cause seals to dryout and so on. I replaced the TC pump seal and axle seals. I put the tranny on its side to soak it with tranny fluid (internally) before I ran it. I also spun the pump shaft slowly for about 5 minutes to get fluid moving before the install. I did this to help prevent any seals from being ripped apart from being dry.
Well It seemed to run fine. But after about 10 minutes it does not always want to go into gear. The tranny is a 4T60. I've had the old one apart to slavage the aluminum out of it. Learned quite a bit about the layout and how it functions, but I'm far from an expert. My concern is what is the mechanics, that causes it to go into gear?
There is a few reason I think this could be happening. One of the "cylinder" valves is sticking. Or possibly a vane is sticking on the pump which would decrease pressure and not cause it to go into gear (if thats how it does it). I've changed the fluid and filter once. Also put lucas tranny treatment in it. I know the tranny isnt controlled electronically to go into gear because I unhooked the harness when it was going into gear good, and it still did. From what I seen when I had the old one apart, There is one solenoid presumably for the TCC, and 3 "pressure sensors." Maybe I'm misunderstanding these, but why have these pressure sensors if there are no shift solenoids that I can see. The haynes manual shoes 2 shift solenoids for 1-2 and 2-3.
The haynes manual of course is of no help. Should I run it more and see if it gets better?
Also since the swap, my oil pressure gauage is reading about 30 psi low. I know its wrong because I've hooked a manual gauage up to it. I need to recheck the wiring harness, but I already have, but going over SERVERE bumps causes it to go back up for a bit.
This move to inprove fuel economy and fixing impending doom from the TC has left me with an unreliable car. Sucks stopping at a stoplight not knowing if its going to stay in gear. BTW, it never drops out of gear when moving. It also shifts perfectly with no hesitation. I've also ran it downhill when it wouldn't go into gear to see if I could bypass first and it did go into second gear.
Any advice would be appreciated.
Necrobater
04-05-2007, 09:21 PM
I got to reading the other thread about a simalar issue and it being a seal. Heres some more elaboration...
Temp does not seem to affect it, sometimes it just doesnt go into gear or when u stop it goes out of gear. Also, its either in or out of gear, revving the poop out of it (not more then 2500rpm so I dont blow something when it engages), has no effect on it and it just doesnt make it go into gear.
When I first added lucas, it seems to fix it for about 10 miles. Ive driven it maybe a total of 100 miles, mostly highway tho. I plan to drive it intown for an hour or so this weekend to give it a workout and hope for the best. I have aklso check the fuid again ,its a red color like should be expected bit is the ever so slightest darkened, which I think it a result of the lucas additive. Doing the blot test yeild nothing that would concern me, not blackness, or particles, all red.
Temp does not seem to affect it, sometimes it just doesnt go into gear or when u stop it goes out of gear. Also, its either in or out of gear, revving the poop out of it (not more then 2500rpm so I dont blow something when it engages), has no effect on it and it just doesnt make it go into gear.
When I first added lucas, it seems to fix it for about 10 miles. Ive driven it maybe a total of 100 miles, mostly highway tho. I plan to drive it intown for an hour or so this weekend to give it a workout and hope for the best. I have aklso check the fuid again ,its a red color like should be expected bit is the ever so slightest darkened, which I think it a result of the lucas additive. Doing the blot test yeild nothing that would concern me, not blackness, or particles, all red.
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