TC lock and unlock

[95blklsc]

I noticed the other day while driving the 95 LSC on this highway at a steady 70 or 75, the TC was unlocking, then staying that way for a minute or so and then locking up. It started doing it again today. It seems to be unrelated to speed, I brought it up to 85, down to 60-65 and it continued.

The lock and unlock is perfectly smooth, I don't expect that it is any sort of mechanical failure. I'm not hitting the brakes or modulating the gas pedal to cause an unlock.

The only thing that I can think of is the temperature has dropped outside and the trans may be dipping below the set point temp that keeps the TC unlocked until it warms up. I do have a standalone 40K GVW cooler. I have that blue thermostat that comes with the kit that is supposed to reroute the fluid back to the trans if it is below a certain temp to prevent over cooling. It is possible that it stopped working properly, I've heard of people not liking that temp regulating module. Although I have the cooler for many years and I haven't ever had it do this. I may block off 1/2 to 2/3's of the cooler to see if that changes anything. It is a very long highway drive to work, that I recently started doing, so it could just be that this is the case.


Any thoughts?

 

[chris2523]

were you running ac or heat?

the compressor cycles when the climate control is on, and i believe the factory tune unlocks the TC when the compressor kicks in, to keep everything smooth and happy i guess.

 

[driller]

Without a transmission temperature gauge, we're just guessing.

It could be too cold?

 

[Meister]

were you running ac or heat?

the compressor cycles when the climate control is on, and i believe the factory tune unlocks the TC when the compressor kicks in, to keep everything smooth and happy i guess.

Mine doesn't do that. I feel the compressor engage and disengage for the AC, but my TC stays locked if I'm cruising.

Doug

 

[KStromberg]

Do you have an aftermarket converter? That is too much cooling IMO if you have a stock converter yet.

Regardless, I thought I heard something in the past about this being normal on these transmissions and the reason for it having to do with the driveline harmonics of the car and keeping everything smooth

On the 2 hour trek to the track over in Wisconsin last year, my car was doing this A LOT. And this is on an $800 Circle D converter that was just over a year old. It never exhibited any symptoms otherwise and I never had any issues with the converter lock-up at the track. I still have that same converter in my car with no issues. I just attributed it to being normal behavior after what I had heard.

 

[chris2523]

huh. maybe not then. i just remember reading about an issue mschultz had when building his car vortech car. but maybe it was something else. anyways.

 

[KStromberg]

huh. maybe not then. i just remember reading about an issue mschultz had when building his car vortech car. but maybe it was something else. anyways.

Without having read the thread that you are referring to I am guessing that he was possibly having issues with the torque converter not being able to hold the power. If you run a single disc lockup like mine on a car like Mike Schultz car, the converter won't stay locked when it is commanded to. There needs to be more clutch material in order to grab and hold on a higher HP setup like he has. I am only going to assume that is why he made the transition to a triple disc converter. Again, just taking a guess.

 

[chris2523]

i know driller had that issue, but i'm pretty sure this was on Mike's car in a cruising scenario. so the lock up on the converter wasn't being stressed. i'll look around.

 

[chris2523]

"The TC would unlock when the A/C would cycle on (or the other way around - I can't remember all he said). This is a Lincoln thing to not disturb the passengers with the engine load change. He fixed that."

that's what im talking about.

http://www.lincolnvscadillac.com/showpost.php?p=301724&postcount=29

 

[95blklsc]

were you running ac or heat?

the compressor cycles when the climate control is on, and i believe the factory tune unlocks the TC when the compressor kicks in, to keep everything smooth and happy i guess.

I was running the heat, no defrost though. I wouldn't think that the compressor would be kicking on. I may unplug it just to test that theory. I don't think this is it just because it seems to coincide with the cold weather recently. It stays locked just fine for about 40 minutes on the highway then starts to cycle. I'm thinking it slowly cools down.

Without a transmission temperature gauge, we're just guessing.

It could be too cold?

I have an infrared temp gun. I can see what he temp coming into the cooler is. I could measure the pan temp too just to gat an idea of the temp.

Do you have an aftermarket converter? That is too much cooling IMO if you have a stock converter yet.

Regardless, I thought I heard something in the past about this being normal on these transmissions and the reason for it having to do with the driveline harmonics of the car and keeping everything smooth

On the 2 hour trek to the track over in Wisconsin last year, my car was doing this A LOT. And this is on an $800 Circle D converter that was just over a year old. It never exhibited any symptoms otherwise and I never had any issues with the converter lock-up at the track. I still have that same converter in my car with no issues. I just attributed it to being normal behavior after what I had heard.

It isn't an OEM converter. I replaced it years back when mine was making a lot of noise during lock up. I forget all of the details. It has a stall slightly higher than stock, but nothing crazy.

"The TC would unlock when the A/C would cycle on (or the other way around - I can't remember all he said). This is a Lincoln thing to not disturb the passengers with the engine load change. He fixed that."

that's what im talking about.

http://www.lincolnvscadillac.com/showpost.php?p=301724&postcount=29

 

[chris2523]

I was running the heat, no defrost though. I wouldn't think that the compressor would be kicking on.

when i cold start my car and the heat starts to warm up the car, the compressor kicks on. i know this because the AC clutch is going out and engages VERY loudly.

next time it acts weird, turn the EATC off. see if it continues.

 

[95blklsc]

when i cold start my car and the heat starts to warm up the car, the compressor kicks on. i know this because the AC clutch is going out and engages VERY loudly.

next time it acts weird, turn the EATC off. see if it continues.

I'll try it tomorrow and see what happens. Although the weather has warmed up so I have to take that into account as well.

 

[95blklsc]

I have an update. The past few days have been warmer and I haven't had any lock and unlock issues on the highway. I was still using the heat since it was between 40 and 50 in my way to work. This morning was in the mid to upper 20's and it started doing it again after being on the highway for about 20-30 minutes. I turned off the HVAC and it continued to do it.

At this point I'm thinking it is probably just getting over cooled. from the long highway drive. I'm going to block off half of the cooler and see how that works out.

I do have that in line temperature regulator that came with the big cooler kit, but it has been on there for at least 7 years. I think it may not be working correctly anymore, I haven't had this issue until this year.

 

[driller]

Wirelessly posted (Mozilla/5.0 (iPhone; CPU iPhone OS 6_0_1 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Version/6.0 Mobile/10A525 Safari/8536.25)

Sounds like the valve is stuck open to the cooler.

 

[95blklsc]

Wirelessly posted (Mozilla/5.0 (iPhone; CPU iPhone OS 6_0_1 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Version/6.0 Mobile/10A525 Safari/8536.25)

Sounds like the valve is stuck open to the cooler.

Yea, I'm thinking that may be the case. I blocked off 2/3's of the cooler fins tonight, I'll see if that makes any difference tomorrow. I'll have to see if I can pick up another temp control module for it, it seems like it has worked ok until now.

 

[95blklsc]

found it http://www.amazon.com/Tru-Cool-Long...08-4739P6/dp/B008BTJFJ4/ref=pd_sim_sbs_auto_4

Depending on how it goes tomorrow with the cooler partially blocked off I may just replace it.

 

[driller]

The same thermostatic valve theory is used on big industrial oil coolers we use at work and they are problematic as well. When they start sticking, we simply replace them.

 

[95blklsc]

I'm pretty sure this is the issue. I blocked off about 2/3's of the cooler with some plastic last night. This morning was about 25F-30F for the entire drive to work and it didn't unlock unexpectedly once. I will give it a few more trips to be sure but I'll probably just order a new valve and be done with it. It has been on there 7-8 years now.