Would like some Transmission info
 

On my 92 I have installed an external cooler in series with OEM, installed a perma-cool filter that replaced the OEM external. I then added a pep-boys transmission oil temp gauge and sender into the perma-cool head.

Ok all that said my temp gauge reads from 140 to 320 and the temp seems to get up to between 230 (gauge center) and 260 on a hot day climbing the 3500 feet from work to home. That seems like it is to hot to me. What could be causing such high readings? The car has around 150K and I have put the last 10 on it since buying it. I would rather fix it now then have it die on me later. Any ideas? suggestions?

Thanks in advance.

PS. How do you tell if the torque converter locks up or not when driving?

Greetings Tom,

As you have put your external cooler in series with the OEM cooler there is still the prospect of the OEM cooler being blocked or becoming blocked and as a result restricted flow and cooling.

Not what I would have done or have done on my car. I have the external and larger cooler as THE cooler and removed the original from the circuit and the trouble equation. It may not be difficult for you, depending on how you have arranged things, to eliminate the OEM cooler and compare temperature readings. If you proceed along these lines please post results as I am sure many will be interested.

You can check on lock up by watching your tachometer while accelerating. If the revs rise faster than your speed rises the transmission is not locked up. Expect some doubts as this is not an easy test to be sure about.

Regards, Trevor.

PS I hope you do the correct thing and drive in 3, i.e. direct drive rather than overdrive, when below 50 mph.

Following fluid flow calculations (detailed more in a previous thread) I would always recommend running the external cooler in parallel rather than series. Any problems with your internal cooler, and the external will do little work.

I would therefore suggest removing the stock cooler at Trevor has suggested, or running a parallel system.

Please post your results as this could make an interesting comparison

Hi Andy,

I gather you have done flow calculations. The interesting conjecture is having established the flow rate between the two coolers in parallel which one, in terms of cooling, is the most efficient and is the lesser inhibiting the more efficient unit ?

Nothing can better practical tests and it is good to see that we both sincerely hope Tom will come to the party.

The figures indicate that in parallel, the volume of flow overall will be greater due to lower system resistance, yet the flow rate through each cooler will be less than if only one cooler is used. This will increase the contact time in the cooler, thereby increasing the amount of total cooling. (In theory )

You are right, Trevor. we now need to do practical tests to see if they follow. Unfortunately, because of my driving conditions, I am unable to do any meaningful back-to-back comparisons, but hopefully tlemmons will be able to do this.

Andy,

The interesting part is that the two coolers will not have the same flow resistance and therefore there will be a greater volume flowing through the one with the lowest resistance. There will be a difference in efficiency resulting from design considerations, mounting position and air flow. If the least effecient cooler attracts the greatest flow due to having the least resistance this could ( ? ) mean the parallel arrangement is inferior to a single efficient unit.

Trevor,

This is a possibility, but unlikely to cancel out the other benefits unless the differences are extreme, ie a 5:1 resistance ratio coupled with a 1:5 cooling efficiency. it is just as likely to be 5:1 and 5:1 giving an even higher cooling effect.

An important consideration in this is that the ATF pump is, I believe, gear-driven and centrifugal, therefore the ATF flow rate will increase in proportion to the reduced resistance.

Not accounting for pipeline losses, if the resistances of the coolers are equal, the flowrate would be double! In reality, there must be considerable resistance in the pipelines and filters, so the increase in flow is likely to be nearer 20%

Just by having two coolers, the flow rate through each cooler will be about 60% of stock (half of 120%) therefore increasing the contact time and the cooling.

Even with the resistance ratio being 5:1 (assuming equal efficiency) the main cooler will have a reduced ATF flow, therefore increased cooling, and the suplementary cooler will have a greatly reduced flow, thereby greatly cooling 20% of the ATF. There will also be the benefits from the increased flow through the transmission.

But at the end of the day, as you have already stated, there is no substitute for on-car trials.

Tlemmons,

Run the external cooler in parallel with your radiator cooler and use synth. ATF. Since you are in the mountains in CO, it gets cold in the winter, so run both coolers in parallel. Also if you are around 5000 ft. above sea level the air pressure is only about 12.4 psia. not 14.7. This makes the air less dense so the external air cooled ATF cooler is less efficient and does not cool as well.
The real fix for you costs big $. First, buy & install a new radiator with the improved cooler (MY '94 and above). Second, buy & install the Level 10 tranny valve kit. This is the one where the flow orifice has an oversize bore (1/16" more, I think) to increase ATF flow.

I think a radiator is $350 and the Level 10 kit is $300-$400.


Good Luck.

Andy you have made an excellent analysis of an interesting conjecture and I am sure you are correct.

Larry please don't put tlemmans to fright with an overkill costing lots of dollars !! ??

Tlemmans you are doing the right thing by exhibiting caution and monitoring temperature. It appears to me that included in your query is a request for typical temperature figures recorded by others with a transducer in the same position. If I am correct you should shout again and out loud.

Thanks Trevor. Yes that is one thing I would like to see. I think the AT temp light comes on at 325 but I am not sure and don't know what a normal temp is. Anyone else out there with temp gauges that can tell me.

My cars trany temp is beween 165 and 200 most of the time. It has gone as hight as 210-225 onces.

I have
B & M Automatic Transmission Cooler 19,000 GVW
in series with stock
Perma-Cool in-line Trany Filter
Auto Meter Lunar Tans Temp Gauge