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Torque Converter Question

amigodana

Well-Known Member
Joined
August 12, 2009
Messages
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City, State
Houston, Tx.
Year, Model & Trim Level
98 Exp 2WD conv. to 4WD
Is it possible that if a Torque Converter is bad that it could show signs of overheating?
 



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I am no authority, but I do recall the display at the transmission shop, of a dissected converter which had signs of overheat, in the clutch area I believe.
 






O/D or Not

I have noticed that I also can cool it down slightly when turning the overdrive on (Lower Rpm's) . And then it generally will heat up more with the O/D turned off (higher RPM's).
 






O.K. So here are the changes I will do. These are the parts I have ordered and waiting on. My research is indicating that it is either the torque converter or shift solenoids, I think. Because I do a lot of towing this would be a good time to change my converter anyway and find out if that is the problem as well.

http://www.monstertransmission.com/AODE4R70W-Torque-Converter-1600-1800-Heavy-Duty_p_5033.html

https://www.lpwracing.com/Trans_Pans/Deep_Transmission_Pans.html

I already changed my gear ratio to 4.10. Hopefully, I can pull a stump with this setup without overheating anything.

Looking for anybody's thoughts on parts choices and other possible upgrades.
 






I have noticed that I also can cool it down slightly when turning the overdrive on (Lower Rpm's) . And then it generally will heat up more with the O/D turned off (higher RPM's).

Are you talking about the engine coolant temperature heating up? If you refer to the transmission fluid, how are you able to determine it's temperature?

Engine temperature does not relate directly to transmission temperature. Yes, the engine might run cooler in O/D, depending on lots of other factors.

Generally unlikely that a "bad" torque converter will be the source of transmission oil overheating, but it is possible for the stator within the converter to "seize", or partially so, and thus generate lots of heat, likely enough to be visibly evident if the converter is opened up. imp
 






Yes, I am referring to the engine coolant making a significant and drastic change visible only on the dash gauge. As of right now I don't have any other means to gauge the temp, for the trans or the engine. That will change however, when I replace the pan with the aftermarket one, so I feel as though I am only gaining by changing the pan. It will have a tap in for a temp sensor, as well as be an improvement for the towing that I already do. So I don't see that as a loss only as an improvement overall!

Now as for the Torque converter, everything that I have read says that the stator can in most instances break the one way bearing which contributes to an increase in the temp of the tranny fluid. Which in turn can heat the coolant since it goes through the radiator.

I am curious about others thoughts on this, as well as other possible sources for the heating such as maybe the shift solenoids. I am pretty confident in it being a problem with the tranny. The engine was just rebuilt by a fairly reputable builder, Port and polished heads, an RV cam, and balanced motor. I have put a descent amount of miles on it to break it in and then some. I feel as though if it had to do with anything other than the tranny it would show itself to be more consistent than such a drastic change after switching the o/d off or on.

Anyways, I also am not losing by changing the torque converter to a lower stall for towing, in my humble opinion.

I guess part of my question would be, do bad shift solenoids always show a check engine light or are there situations where they go bad and show no other signs other than what I am experiencing?
 






I would expect the temp of the transmission and engine to be higher with higher RPM's.

The transmission will get real hot if it can't remain in lock up, so if you are keeping it out of overdrive you may also be keeping the converter from going into lockup.

Only the converter will generate any heat, the solenoids won't heat the fluid at all. Overheating converters are due to a slipping clutch inside the converter or low cooler flow.

If the stator breaks or splines fail inside the converter or on the pump the symptom will be a very high stall or it just wont move, and there is generally noise associated with this.

I am not sure that your "overheating" problem that you are noticing with your engine temp gauge is going to be related to your transmission if it has all the gears and lockup.
 






Does your transmission fluid smell burnt?

The engine coolant system moves a lot of water and displaces a lot of heat.

The amount of thermal energy you would need to put into the system by using the radiator mounted transmission cooler to drive the engine coolant up should burn the transmission fluid in short order.

Perhaps check other sources of water temp increase before condemning the transmission.

Perhaps the fan clutch first?
 






Does your transmission fluid smell burnt?

The engine coolant system moves a lot of water and displaces a lot of heat.

The amount of thermal energy you would need to put into the system by using the radiator mounted transmission cooler to drive the engine coolant up should burn the transmission fluid in short order.

Perhaps check other sources of water temp increase before condemning the transmission.Perhaps the fan clutch first?

It will help definitely to establish that the engine's cooling system is functioning properly. Considering the lesser cost of two testing options, without actually beginning any major transmission work, I would temporarily mount a fairly good-sized oil cooler in front of the radiator, then disconnect the cooler lines from the car's radiator and re-route them to the outside, air-cooled coil. This removes the question of heat being dumped into the engine's cooling system. Drive the vehicle thusly awhile, and see if the engine temp. remains where it should be. If it does, suspect the transmission as contributory. If it does NOT, then something is afoul in the engine's cooling ability itself.

True, eng. coolant can remove a lot of heat from trans. fluid, but keep in mind that the trans. fluid temp. MUST be higher than the eng. coolant temp., to effect cooling of the transmission. Otherwise, the trans. fluid is COOLING the eng. coolant. The important thing is the TEMP. DIFFERENCE between the two media, let's say, 195` eng. coolant "cooling" 215` trans. fluid, a "Delta-T" of 20`. With the air-cooled coil outside the radiator, ambient air, let's say at 80` is cooling the 215` fluid. Which situation do you feel is more effective? Yes, there's a lot of factors I'm neglecting. IMO, it would be worth spending 40 bucks or so, and installing an outside oil cooler, to learn that the trans. itself is OK.. imp
 






The reason I began the rebuild on the engine to begin with was because of a coolant leak on the pump. As you know, you pretty much have to tear down the whole front to fix that issue. I had the time and money so I decided to go ahead and rebuild the entire engine. Too many miles and it needed the upgrades.

My cooling system, pump, hoses, and my radiator are in top condition. And my clutch fan is also new and I looked at the new one too. All these things are in top condition (been replaced and new).

My fluid does not smell burnt, I imagine that it will if I keep driving it like this though.

Yes the cooling system removes a lot of heat and it does just what it is supposed to do, that is why it cools down so drastically and quickly after the condition (extra stress) changes.
 






Also, let me add that I have two stock tranny coolers in series mounted up front. It helps with the cooling.
 












Well, for an update. I completed the work and took it up into the mountains pulling a fairly decent load and I have not had any issues as of yet, like what I was having. So, I think I have the problem fixed. Thanks for everyone's questions and input! AS time goes by and I do some more towing, it will prove whether or not the problem really has been fixed though.
 






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