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Is my tranny making my truck overheat?

jonrpick

jonrpick

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Bah... I don't want to get into it all, but the plain truth of it is, the truck started overheating after the tranny was replaced.

700R4

My lockup wiring was MIA after an engine fire. The dude at the tranny shop said he'd put a mod in to make it lockup without the harness. I don't know how it was supposed to work, but he said it was the same thing he used to put a 700R4 into older GM sheetmetal.

Either way, it's out of warranty, and probably had 1000 miles on the rebuild.

I need some opinions here, as well as possible solutions. What are the alternate means of locking up a tranny? I know that when you tap the brake pedal, the RPMs don't go up like they did when it was electronically controlled.

Discuss.
 
I know we discussed this some when you stopped by. How long does it take to overheat? Does it overheat at idle or while driving? Does outside temp affect the condition?

Also, the trans cant be the cause. The converter staying locked would actuallly reduce trans temp because there is no slip in the converter clutch. The slipping is what causes alot of 700's to fail. If the trans is getting hot enough to raise engine temp then the fluid would be wasted already. It doesnt take long.
 
I dont think the tranny is the problem. Check the coolong system. Fan clutch? Thermostat? Radiator clogged?
There are a number of aftermarket TC lock up kits available.
like this:http://www.jegs.com/webapp/wcs/stores/servlet/product_10001_10002_748599_-1_10733
If the TC is unlocking when you tap the brakes it is working right.
As said above the TC locked helps cool the transmission.
Check the tranny fluid. If it smells burnt and is brown in color you have a trans problem.
 
JBo214 said:
I know we discussed this some when you stopped by. How long does it take to overheat? Does it overheat at idle or while driving? Does outside temp affect the condition?

Also, the trans cant be the cause. The converter staying locked would actuallly reduce trans temp because there is no slip in the converter clutch. The slipping is what causes alot of 700's to fail. If the trans is getting hot enough to raise engine temp then the fluid would be wasted already. It doesnt take long.
Click to expand...

Yeah, I know... I thought about it a bit more. I'm not sure it's locking up as it should. It only overheats while driving, not while idling. You can let it idle for 20 minutes and the temp will stay normal, start driving and it goes up almost immediately.

Thunder said:
I dont think the tranny is the problem. Check the coolong system. Fan clutch? Thermostat? Radiator clogged?
There are a number of aftermarket TC lock up kits available.
like this:http://www.jegs.com/webapp/wcs/stores/servlet/product_10001_10002_748599_-1_10733
If the TC is unlocking when you tap the brakes it is working right.
As said above the TC locked helps cool the transmission.
Check the tranny fluid. If it smells burnt and is brown in color you have a trans problem.
Click to expand...

It does NOT unlock when you tap the brakes. I don't think it's electronically controlled anymore. I could be wrong. Can the lockup kits be installed without removing the entire tranny?

Fan clutch shouldn't make a big difference while moving should it? Thermostat was changed, no effect... Radiator is only a few years old. I pulled it a while back and checked it. It looked ok. I ran some Prestone de-clogging agent through it several times, and even tried the old trick of filling the radiator with vinegar and then draining it. I also pumped lots of clean water through it each time until it ran clear after a cleaning.

No difference.
 
Well if the fan clutch is not working it will the fan will spin slowly and actually block the air from going though the radiator to a point when you are moving. Or not work at all to pull air through the radiator
 
As I recall from a friend that used to have a tranny shop, you simply install a ball bearing (check valve) into the TCC snout, and you end up with lockup with no electronic control. It's immediate so you don't see the TCC apply.

My friends Monte Carlo is setup this way, no problems with it so far, and it's been quite a few years.
 
kgblazerfive said:
Well if the fan clutch is not working it will the fan will spin slowly and actually block the air from going though the radiator to a point when you are moving. Or not work at all to pull air through the radiator
Click to expand...

Dabba said:
then it wouldnt it overheat while idleing?
Click to expand...

My thoughts exactly... It does NOT overheat while idling.
 
dyeager535 said:
As I recall from a friend that used to have a tranny shop, you simply install a ball bearing (check valve) into the TCC snout, and you end up with lockup with no electronic control. It's immediate so you don't see the TCC apply.

My friends Monte Carlo is setup this way, no problems with it so far, and it's been quite a few years.
Click to expand...

So what happens? When you give it gas, does the pulling of the TV cable increase pressure and open the valve, thus unlocking the TC?
 
Nope, keeps locked up until it shifts down into *I think* 2nd. 3/4 are always locked.
 
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