Line pressures

[SRehberg]

I was wondering if you guys could enlighten me on what trans pressures you are running with a stock 47re; Mine is a '96 2wd, and the line pressure is turned up to: 65lbs. @ idle and 72lbs. @ 1000RPM. I'm having torque converter lockup problems (i. e. after it unlocks at freeway speed, it doesn't want to relock). Just wondering if the increased pressures might have something to do with it. The dealer is at a loss and says the scan of the electrical is o. k. However, they don't have the appropriate scan tool to check it while running down the road, or don't know what to do. Otherwise the trans is stock except for the seal and drum upgrade on the front clutch.



Thanks!





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'96 2wd, auto bone stock

 

[Dieselnerd]

You might want to remove the transmission relay and jumper the two left hand contacts as viewed from the top. (Follow relay jumper instructions on TST web site if you need help) If this solves your problem just leave it that way. The relay isn't really needed, it was added in 1996 and from what I remember it was to make it harder to install a "Mystery Switch" and is just one more place that can disrupt your lockup by malfunctioning.

 

[SRehberg]

Thanks for the reply, as the dealer sure is guessing. You would think they would have someone knowledgeable in troubleshooting the electronic controls. What bothers me is the fact they don't own a mobile scanner! Everything was o. k. until the dealer rebuilt the trans, so I don't know what they did. I tried the mystery switch, and pulled the relay out jumpering the contacts. Major mistake. After about two times of trying the switch, the TC locked up and wouldn't unlock, even with the switch off! Coming to a stop was a real experience, similar to not pushing the clutch in on a manual trans when stopping. Sure did buck and jump. Had to kill it with the ignition switch, then things were o. k. once again, but needless to say, the switch was removed. The time I tried it though, it would lock up the TC in 2nd, but not 3rd, go figure. This thing is weird. Have you ever cranked up your line pressures? If so, how much did you go if you did?.



Thanks for the input, this thing is driving me nuts.



________________________



'96 2wd, bone stock

 

[Dieselnerd]

SRehberg, my line pressures are much higher than yours since I have a modified transmission. My max pressure when locked up is 140 if I remember correctly. Since lockup is both electric and hydraulic it's easier to check the electric first. I don't see how higher pressure would keep it from locking up as long as the lockup solenoid is operating correctly. Higher pressure should make it lock better not worse. When the transmission was rebuilt I suppose it's possible something was done to cause the problem but if it does lock up but then won't lock again after it unlocks sure sounds electrical to me. Possible electrical causes are:

1. Transmission relay

2. ECM

3. Throttle Position Sensor (TPS)

4. Brake light switch

5. Connector plug near top on drivers side of transmission. This gets pulled off when transmission is removed, check and reseat. The lockup signal goes through this connector.



These are not in order of probability but just the order I thought of them. If I have forgotten anything I'm sure someone else will think of it. One other thing, does it lock up in third gear when you have the overdrive turned off? If it locks up then and stays locked up I think it's almost certain to be electrical.

 

[SRehberg]

line pressure

Thanks for the information regarding my problem. Everything works great when things are cold, for the first 5miles, then it falls apart. It will only lock up in 3rd when cold (with OD disengaged) then when it gets to the 5mile mark, if it gets disengaged, it'll never lock up again. Now, if you have OD engaged, and start from a dead start, hot or cold, it will lock up everytime going up through the gears; just don't hit the brake or let off the fuel aburptly. It then refuses for long periods to come back in. If you pull over and go up through the shift sequence again, all is well, until it gets disengaged again... . strange huh?! If you are going down the freeway, and it gets disengaged, you can turn OD off, then back on, then the TC and OD come in together at the sametime. Weird.



I've tested the TPS and it appears to be linear. The brake light switch checks out. The connector at the trans I wiggled it and pushed it on to insure tightness, but I haven't removed it and replugged it in. I'll give it a go, but it does work normally like I described above, so I think it will check out too. But who knows.



Dodge says it is acting normally, which must mean when it was new, it was abnormal, functioning the way it was suspose to. It all started after the rebuild.



I'm open to all suggestions/solutions.

Thanks for all the help, this one is a strange one.