: 1984 Brougham <DIESEL> Torque Converter Clutch Issue 2004R Help



tqwrench
05-23-11, 05:16 PM
I recently acquired a 1984 Fleetwood Brougham Coupe with the 350 Diesel. Yes, yes, I know, the most beloved engine of all time...

I've worked through some issues with the engine and also reconnected the Torque Converter Clutch (TCC) circuit. Here is my issue and I hope someone can either refresh my memory or point me in the right direction:

Intermittently, I get a pretty violent buck/jerk/clunking at around 45 MPH, usually after any time cruising on the highway (hot). I've noted that this is about the same speed that the converter locks/unlocks at. Typically it presents itself if I pull off the freeway and enter a local/country highway where the speed limit is 45-50 MPH and it's almost as if the converter is locking/unlocking. When it starts doing it, I decelerate to below 45 MPH for fear it will break my crankshaft or at least the #3 main thrust bearing : 0

Bear in mind this is a Diesel so there's no ECM. The car has the 2.93:1 axle ratio, and as far as I can tell the converter is intended to lock up only in 4th on this model. I remember my mom had an '84 Delta 88 (307 gas) that would do almost the same thing intermittently, more so when the trans was good and hot. I'm almost 100% this is NOT from the engine.

Is the governor switch (hydraulic) sticking or binding? Is there a fix for this?

cadillac_al
05-23-11, 06:26 PM
I would try adjusting the TV cable. I had a similar car and when we converted from diesel to gas the trans never shifted the same. I didn't know how to adjust the darn things back then but I'm pretty sure that would have cured it. Here is a link to some reading:

http://www.tvmadeez.com/article/index.php

cadillac_al
05-23-11, 06:27 PM
I would try adjusting the TV cable. I had a similar car and when we converted from diesel to gas the trans never shifted the same. I didn't know how to adjust the darn things back then but I'm pretty sure that would have cured it. Here is a link to some reading:

http://www.tvmadeez.com/article/index.php

sven914
05-23-11, 06:29 PM
A lock-up convertor uses a computer signal to activate. I'm not familiar with the 350 diesel, but I know they were connected to the THM200-4R transmission, which had the option of a non-lockup convertor.

tqwrench
05-24-11, 08:57 AM
Thanks Al & Sven. I'm not sure what role the TV cable would play in converter lock/unlock, if any. Maybe to change overall line pressure, but if I remember correctly, the converter uses cooler return oil pressure to disengage and remain held off. The transmission calibration is handled primarily in the valve body, so if one were to convert to a gasser, you would likely have to change the valve body as well. I do know that my car will shift into overdrive at about 32 MPH at light acceleration which is consistent with where the engine builds its torque (on the low end), unlike the gassers that would never see OD until 40 MPH. Not all converter lock ups need an ECM. My uncle and brother both had '86 Suburbans with gas 350 Chevy motors. They used a power wire to the TCC and a series of switches both electrical and vacuum to break/complete the circuit to it.

sven914
05-24-11, 09:33 AM
I've seen the vacuum break ones and I didn't thing they would put that on a diesel; they don't make a lot of vacuum. I've never heard of a hydraulic converter clutch though.

If the TCC uses a switch to sense the pressure, which sends an electric signal to the clutch, you can try disconnecting the TCC solenoid. It is located behind the trans pan, near the valve body. Driving with the TCC deactivated will have no detrimental effects and if there is a problem with the pressure switch or the solenoid, your drivability concern will go away. The clutch is only really there for economy reasons, and no having it will decrease your overall fuel efficiency by 1-2 miles per gallon.

tqwrench
05-25-11, 11:07 PM
Essentially, the TCC solenoid is hot all the time unless the circuit is broken by the brake pedal being depressed, a temperature switch (prevents it at cold temps), or an electrical cutoff after 3/4 accelerator pedal position operated off the side of the injection pump. The remainder is hydraulic inside the trans. All 200-4R will not allow lockup in 1st, some allow it in 2nd, 3rd, 4th, some in 3rd and 4th, and as far as I can tell this one only allows it in 4th.

With that being said, something is going wrong around 45 MPH, this thing appears to be going in/out of TCC apply pretty violently. It's almost as if an internal valve is hanging or shuttling. A valve that has governor pressure on one side and a spring on the other. I don't know where it is. Is it in the pump? The valve body? At least then I know where to look. If it's in the pump then I move on to my worst case scenario: I lock the thing in 3rd if I'm expecting to travel at under 50 MPH I guess.

sven914
05-25-11, 11:42 PM
It would be the valve body; all of the hydraulics run through there.

You should still disconnect the TCC to see if that makes your problem go away.

turbojimmy
05-26-11, 12:14 PM
Have you replaced the TCC solenoid? They're notoriously bad. The one in my Fleetwood is doing the same thing, getting worse by the day. I put in like 4 of them in the 10 years I owned my Grand National (2004R).

tqwrench
06-11-11, 10:43 PM
I believe I got this fixed, or at least it's as good as it gets. For one, the TCC solenoid was bad. You can easily tell if the converter clutch is on during decel in this car, it actually has more engine braking, and you can feel it disengage at around 45 MPH on a decel. Well, while decelerating with my foot off the brake I tapped the brake enough to turn on the lights but not slow down and the sound didn't change, it was stuck on mechanically. Changing the TCC solenoid fixed that.

Now, strangely enough, the TV cable adjustment DOES affect TCC, however ONLY on the Diesel since it has no ECM. I had a closer look at the hydraulic circuits in the shop manual and there's a hashed box that says non-CCC (computer command control) equipped (no computer). Maybe they exported some models that used this trans with gas engines w/o CCC as well IDK.

While working on the timing and making some throttle adjustments, I adjusted the TV cable and got another improvement in the shift characteristics. If I really try, I can force it to trailer hitch at 45 MPH now, but it's a hell of a lot better than it used to be.

What remains may be leakage in the TCC circuit, those o-rings on the stator shaft were notorious...I'm gonna let that sleeping dog lie for now.