[Simmer71]

Hi everyone, again. On top of other issues with my Shadow, the other day I noticed the transmission was not letting the lock up converter engage. I didn't feel that extra "shift" it usually does around 35 mph, and the rpm's of course were higher than usual. I did the "key on, key off" way to check the codes and there was a code 37, the lock up control circuit. Here are my questions:

Is it ok to keep driving the car with it not locking up?

If it was to be a bad sensor, how hard would that be to replace?

Would doing a drain and refill help matters any?

It's a 92 Shadow, with 87K and the 3 speed auto.

 

[John Wood]

It is OK to keep driving the vehicle. The most common cause of the code 37 is a loose/dirty connector on the transmission near the dipstick hole (lockup converter plug). First try to remove and re-seat that plug to see if that corrects the lockup function.

 

[B10alia]

If it was locking up and then suddenly stopped, I would bet it's the electrical connector, like John said. The TCC is a pretty simple unit; as you probably know, it's an electromagnetically engaged friction clutch, not entirely unlike the clutch that engages the blades on some lawn tractors. I would only be worried about driving the vehicle if you were gradually losing lockup or had discolored ATF.
In addition to a dirty or loose connector, it could also be loose contacts inside the connector itself. I'm not exactly sure how this plug is set up, having never had to remove it on my Spirit, but if it's a boot with pins that go into it, the contacts inside the boot can lose their spring and stop gripping the pins properly. Someone on here (IIRC, one of our overseas members, possibly RaiRai) had a contact problem with that style connector and fixed it by squeezing the boot with a pair of pliers so that the contacts got their spring back. Either way, I would definitely recommend dielectric grease on this contact; it's in an exposed spot and could probably use the help.

 

[Simmer71]

Thanks for the replies, the issue comes and goes, today it was engaging like it should be. I will try and clean the connector, squeeze it with some pliers and use some dielectric grease on it. It is pretty nasty around that area. The fluid, which I really hate to say, is most likely the original fluid the car came with, with 87K on it, it's a reddish brown color, (i know it's supposed to be actually red) but I am afraid to change it because of the whole "it may be keeping it going and changing it might make it worse" things. I can say also, the bands have probably never been adjusted either.

 

[B10alia]

The A413 isn't anywhere near as finicky as the A604. It's a straight hydraulic transmission, so fluid isn't nearly as critical as in the A604. The 604 uses PWM on the converter clutch to soften lockup, so there are points when you're driving around with the TCC partially engaged. I believe the gearshifts use PWM to soften them as well; the shifts in an A604 are all clutched, there are no bands. Obviously, you can see why you'd have problems with a fluid that doesn't have the right properties in a transmission that operates like this. With the A413, the shifts are much more on-off, so fluid quality isn't critical. I've heard you can get away with Dex/Merc or Type F, but I would recommend ATF+4, which superseded the Type 7176 that's specified on the dipstick. Bad fluid will eventually harm any transmission though, so I would change it soon. You're not going to hurt anything by changing the transmission fluid.

 

[Simmer71]

Ok, then I will change the fluid, thanks. Also, thanks for explaining the two transmissions. So, is the A413 the 3 speed, and the A604 the 4 speed then?

 

[Oklahoma Wolf]

My second 1988 New Yorker ran without lockup the entire time I had it... was still working fine when I sold it. Was still working fine when the new owner sold it.

On that car, the issue wasn't the connector - the lockup solenoid coil was open. Thought about dropping the valve body to replace it but never did.

I should have kept that car in addition to the Imperial and not sold it. The last guy to own it blew up the transmission and a replacement transmission doing repeated neutral bombs and burnouts. Almost a thousand bucks of my money into the engine, and IIRC he somehow took that out too. Probably a good thing he doesn't live anywhere nearby... I'm still rather upset with that guy three years later.

 

[Simmer71]

I know how it is to sell a car to someone and see or hear about them destroying it. I had a 89 Corolla that I had for about 7 years and put close to $1200 into it over those years. Only to sell it to some dumb 16 year old who in the first two weeks he had it, he hit the side of car and tore off the passenger fender. Then, a week after that, he got the car stuck in some mud and had his buddy hook a tow strap to the bumper cover to pull the car out and tore off the bumper cover.

As far as the lockup converter goes, without it engaged, it sounds like the engine is just screaming along. I don't have a tach on the car, but I know the rpm's are pretty high. I guess I just got used to 4 speeds with overdrives not making suck a racket.

 

[Bob Lincoln]

The lockup only drops the RPM by about 200, so there should be little difference - it should not "scream" in comparison to it being locked up. At 70 mph it will turn about 3,000 RPM normally; 3200 unlocked. Do you have a tach?

 

[Simmer71]

No tach on the car, I wish it did though. I can't be certain, but at 55 mph it seems mine is probably around 3,000 rpm. 70 mph is more like 4500 rpm. The engine is very loud at 70 mph, so loud in fact, I don't like driving it that fast. Even my dad who is a tech says it sounds like the engine is spinning to fast for it's speed.

 

[John Wood]

No tach on the car, I wish it did though. I can't be certain, but at 55 mph it seems mine is probably around 3,000 rpm. 70 mph is more like 4500 rpm. The engine is very loud at 70 mph, so loud in fact, I don't like driving it that fast. Even my dad who is a tech says it sounds like the engine is spinning to fast for it's speed.

That really doesn't sound right. I think when my Dodge Spirit is at about 69 to 70 MPH, the tach is reading about 3000 RPM.

Is this the original transmission? I ask because I had a mini-van 2.5, 3 speed transmission in an EEK car once and that tranny ran a few 100 RPM's higher at highway speeds. The mini-van trannies are geared differently (in the differential), but will mate up fine to the 2.5's or 2.2's in our EEK cars.

 

[Bob Lincoln]

No tach on the car, I wish it did though. I can't be certain, but at 55 mph it seems mine is probably around 3,000 rpm. 70 mph is more like 4500 rpm. The engine is very loud at 70 mph, so loud in fact, I don't like driving it that fast. Even my dad who is a tech says it sounds like the engine is spinning to fast for it's speed.

Sounds like it's still in 2nd gear, not in 3rd gear with torque converter unlocked. Either that, or you're not judging it quite right. But you should feel the 1-2 and 2-3 shifts.

 

[B10alia]

I have a tach on my Spirit, and she runs right around 3500 at 75, so if you think your'e running 3K at 55, something almost certainly is wrong. My Spirit loves 55, very quiet and smooth, so if yours is loud and seems unhappy, I would agree with Bob that you may be in second. If you're moving along steadily at about 40-45 (the maximum recommended speed for "2" in the manual) and you shift from D to 2 and nothing happens, there's something wrong inside the transmission itself or a linkage is not adjusted correctly. I had no upshift to third after I adjusted my bands because the locknut on the outside of the case had backed off and allowed the screw to back up, loosening that band. The kickdown/throttle pressure linkage may also be at fault here, although this is really only a guess, as I don't know my way around the transmission all that well yet.