I went to camping about 2 weeks ago and I loaded my car with all my camping gear (so 2 people in the front plus camping gear). I wouldnt say that I overloaded the car because it definitly lighter than sitting 3 people in the back. Anyways, we were on the way to the park and there was a long stretch of uphill road for 35 miles. The outside temperature was low : 54F around 10pm at night. But my tranny temp gauge was indication 240F . That is way too high and I've never ever been there before even when I had my car supercharged. My tranny temp reading in stop and go traffic is around 180F with 75F ambient tempearture. I stopped the car couple times to cool the sucker off and it did go back back to 180F. But once I got it going, it jumped back to 240F again!

I pulled out the tranny dipstick and the fluid is not burning and it is still red (I changed it 10k miles ago)

my conclusion:
the traditional tube and fin cooler is not capable handling modified vb when the car is under load.

I already bought a B&M stack-plated cooler. It is a larger and thicker cooler than the Hyaden 403 that I am using. I will do a study on its performance by using my tranny temp gauge after I installed it. I will keep you guys updated.


btw, has anyone noticed this problem before?


thx

I don't think the VB mod was the cause of your high tranny temp. It was the load. ie. going up hill for 35 miles. I'm sure a non-VB mod maxima will get that high. The seals would start to be harden around 270F. At 240F, your tranny fluild life expectancy would just decrease. Anyway...flush the tranny fluid regardless if you upgrade the cooler or not.

I'd say it was the load of going uphill also.

I agree with Tony & Dana, the tranny was getting hotter based on the load/hill it was pulling. The VB mod does nothing but minimize shift lag and increase the quickness of the shift. It would be the same if I was pulling with my SUV, it would be added load and it would increase temperature accordingly....

If your transmission is shifting a lot to get enough power to go up the hill, it'll get hot.

well what happened on your way home ie going down hill?

The torque converter generates the most heat in your tranny. If your under load with the converter unlocked, your gererating massive amounts of heat. The more you keep it locked up, the less heat your going to generate. Feather the gas so it stays locked or switch to OD OFF and see if that keeps your tranny temp down a bit.

I wish you guys were right. but my car was not overloaded. My camping gear is definitly less than 150lb. It is already 240F with only 2 passengers and camping gears. What if there were 4 passengers?

cultr7 - the vb mod also generates excessive heat to the ATF. that's why a cooler is highly recommended.

there was not much shifting. this was a long uphill road, no stop sign and lights.


the temperature dropped as expected.

I always keep my OD off when I am driving at low speed.

I think you should've bought the 404 cooler instead of the 403 since the 404 is for heavy duty driving and the 403 is for medium duty driving.

did you check to see if maybe one of the hoses is pinched a little and underload it showed itself?

JaTaN and C Max both make good points. I remember Woo losing his tranny to a pinched line.

404 may be too big for our car. IIRC it is designed for trucks and SUV. Unlike B&M coolers, Hayden is not pressure regulated. That means when the ATF is cold (i.e. start-up), the pressure might be too low for the transmission to operate properly.




It had a minor leak at the ATF return line. but I am sure the hoses are not pinched.

How steep was the grade and how fast were you going? Anything under 45mph on a steep grade should be in 2nd gear with the automatic.

As for tranny coolers, bigger isn't always better.

I dunno precisely how steep was it. It varies. but overall I would say around 10% the most. Going about 45 - 55 in 3rd gear.

this is the tranny cooler that I just bought:

70264 SuperCooler 24,000 GVW 11"x6"x1-1/2"

I'm stiill don't understand how the VB mod increases tranny temps, especially if no gear changes are involved.

In the last thread about this topic, Quicksilver brought up a good point that in a closed system, increased fluid pressure would result increased temperatures. However, isn't fluid pressure only increased during shifts and couldn't the quicker shifts of a modified VB negate those heat resulting from increased fluid pressure.

In your case, no gear changes were taking place so what mechanism would cause the increased tranny temps?

that's a good point. I was cruising at a constant low speed with no shifting. My explanation would be - 1.the tranny temp was elevated by previous shifting and the coolers were ineffective in lowering the temp. 2.traveling at low speed does help the air-cooled cooler to lower it. 3.I overloaded my car and the hill was too steep.

you didn't overload your car, but its the extra load and the long stretch of hill that your car had to climb that caused the temp to jump. It was all generated by the torque converter. Torque converter spin all the time and the faster it spins the more torque is generated (to a crtain extent) but at the same time it slips causing heat to be generated.