Alphius Posted January 7, 2009 Share Posted January 7, 2009 I've got an interesting problem here... My '87 Turbo wagon has been really great, running and driving awesome. The other day me and some friends were driving down a gravel driveway, and I needed to turn around. There was a pullout big enough to do a 3-point turn and head back the way I came. Drove in, popped it into reverse, and no go! We had to call somebody to pull us backwards enough, and then I could continue on my way perfectly fine in drive. Here are the symptoms of what is going on: All gears seem to have drive engaged no matter what... hard to explain, but here goes. Park - RPM's do not increase when I shift to park, and when I push the gas, the engine seems to load up against the torque converter instead of free spinning. Reverse - Same. Loads the converter without going anywhere. Neutral - Drives forward. Seems to stay in 1st gear though. Drive - Works fine, shifts through all three gears. 2 - Holds 2nd gear, just like normal. 1 - Holds first, again working just fine. So it seems as if all positions of the gearshift also engage Drive at the same time. Is something unplugged, or did I frag something internal? Also, possibly unrelated, there is a vacuum line going from the center top of the 3AT towards the driver's side, and it just ends. It isn't plugged into anything, and I can't see where it should go. The short vacuum line to the tranny from the engine is still plugged in. Help!!! I need my winter car! Quote Link to comment Share on other sites More sharing options...
bratman18 Posted January 7, 2009 Share Posted January 7, 2009 I bet it has something to do with that vac line. It has to go somewhere and these trannys rely on vaccum to work. So I would look to see where that vac line could go Quote Link to comment Share on other sites More sharing options...
Skip Posted January 8, 2009 Share Posted January 8, 2009 The rubber line you see is probably just a vent tube for the front diff The vacuum Bratman mentions on a 3AT is just for the vacuum modulator (down shifting on hills ect) Your problem sounds like the shift linkage is knackered somehow. Jack it up crawl under and examine the linkage connecting the shifter to the tranny. Something slipped or is not moving what it's suppose to where the cable from the shifter connects to the tranny linkage. Quote Link to comment Share on other sites More sharing options...
bratman18 Posted January 8, 2009 Share Posted January 8, 2009 the rubber line you see is probably just a vent tube for thefront diff the vacuum bratman mentions on a 3at is just for the vacuum modulator (down shifting on hills ect) your problem sounds like the shift linkage is knackered somehow. Jack it up crawl under and examine the linkage connecting the shifter to the tranny. Something slipped or is not moving what it's suppose to where the cable from the shifter connects to the tranny linkage. +1 Quote Link to comment Share on other sites More sharing options...
Alphius Posted January 8, 2009 Author Share Posted January 8, 2009 The rubber line you see is probably just a vent tube for thefront diff The vacuum Bratman mentions on a 3AT is just for the vacuum modulator (down shifting on hills ect) Your problem sounds like the shift linkage is knackered somehow. Jack it up crawl under and examine the linkage connecting the shifter to the tranny. Something slipped or is not moving what it's suppose to where the cable from the shifter connects to the tranny linkage. I have verified that the shifter goes through all positions just fine, and moves the linkage as it should, corresponding to how far I move the shifter. The linkage is actually solid steel rod, not a cable, and seems to be in the correct place. My bet is something is chewed up internally because the tranny seems to engage all of it's gears just fine, in sequence, just with drive applied all of the time. Look back to my first post. Every shifter position is engaging two gears. Drive + whatever the shifter is in. I don't know enough about these trannies, so I was hoping there was a modulator or solenoid that may have broken. Thanks for your input. Quote Link to comment Share on other sites More sharing options...
Skip Posted January 8, 2009 Share Posted January 8, 2009 You are correct sir, my mistake the cable if for the 4EAT The only solenoid is for the 4wd engagement (the 4EAT has some internal not the 3AT) and the only modulator is the vacuum one I mentioned. I got out my FSM (Factory Service Manual) and the internal shifting is controled by the lever you see operated by the shift rod. Like you said, something internal appears to have come loose. and is allowing the hydraulic fluid to be moved where it should not. If you would like I will examine this in the FSM to a more exact degree. Quote Link to comment Share on other sites More sharing options...
Alphius Posted January 8, 2009 Author Share Posted January 8, 2009 Thank you very much for your offer Skip. If you have the time to look in your FSM for me, I would love to know more about what may be busted up. I don't relish the idea of tearing the pan off without at least an inkling of where to look for damage. And I hope very much that I do not have to pull the transmission to fix whatever may be the problem. In a perfect scenario, I would like to take the pan off, pop in a new (junkyard) part, and be on my merry way in half an hour. Knock on wood... Quote Link to comment Share on other sites More sharing options...
Quidam Posted January 8, 2009 Share Posted January 8, 2009 "there is a vacuum line going from the center top of the 3AT towards the driver's side, and it just ends. It isn't plugged into anything, and I can't see where it should go." That is a vent, so no worries there. Doug Quote Link to comment Share on other sites More sharing options...
Gloyale Posted January 8, 2009 Share Posted January 8, 2009 You could try a new valve body in it and see if that does it. It could be just a matter of a seal between two passages that blewout. It sounds a bit like you have chewed up the one way *sprauge* type bearing. It locks in one direction to prevent the sun gears from rotating to engage reverse. Doesnt really explain the drive pressure in P though, so it may be a valve problem. But for the trouble you could almost just throw in another 3at. Although changing the valve body could be done easily with trans in car. Quote Link to comment Share on other sites More sharing options...
Quidam Posted January 8, 2009 Share Posted January 8, 2009 "Help!!! I need my winter car!" Well, did you check the fluid? What does it smell like? It's no big deal to pull the pan on these, btw. They also have a drain plug in the pan. Every pan I've pulled off of 3 of these has had a lot of crap in them. It's clear to me that they all weren't serviced proper. Deposits can and will build up and cause issues. Dextron has good detergents in it, but if it's not changed, it goes to crap for fluid. hth Doug Quote Link to comment Share on other sites More sharing options...
Quidam Posted January 8, 2009 Share Posted January 8, 2009 You could try a new valve body in it and see if that does it. It could be just a matter of a seal between two passages that blewout. Doesnt really explain the drive pressure in P though, so it may be a valve problem. . I just looked in the 87 FSM. What he describes comes back to the "Control Valve". The valve body. Doug Quote Link to comment Share on other sites More sharing options...
Alphius Posted January 12, 2009 Author Share Posted January 12, 2009 Thanks a lot for all your help guys. Fluid is good, red and smells fine. I guess I'll be taking the transmission apart soon and getting that valvebody out. I can do this in-car, right? I've had tons of tranny experience with Chevy transmissions, I'm just trying to beware of anything different on this car. Again, great to be part of this group. Thanks guys. Quote Link to comment Share on other sites More sharing options...
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