Trans running hotter

Dieselboy. · May 26, 2012

Any idea what would make my trans temps jump up. Usually I can barely break 140*. Today on the hwy it slowly crept up to 170* and doesnt cool as fast. It fluctuates between 160-170 driving on the hwy and in town.

I even let it idle for about 5 min and it barely dropped the temps. Like I said it has been hard for me to break 140*. Trans is a full built NADP race trans with maybe 5k miles on it.

Is there anything that could restrict flow to the cooler or plug up in the trans and cause it to run hotter ?

I have the 6.0L cooler and deep sump pan on it, the trans doesnt seem to show any signs of slippage in any gear.

Fluid is red and still smells fine. Dont think its the gauge because the pan does feel hot.

Groomzybanshee · May 26, 2012

The hotter it is outside the hotter your trans will be..

Dieselboy. · May 26, 2012

Groomzybanshee said:
The hotter it is outside the hotter your trans will be..

Last weekend I drove the truck home from spokane (7 hrs) strait and even maintaining 65-70 MPH up through the snowqualmie mountain passes it didnt go over 140*

I drove it 15 min at 60MPH and it climbed from 120-170 in that time and wont cool off.

Something is causing the heat. It hasnt gone over 135* driving to work and back all week. And I sit in 1 hour of bumper to bumper traffic at 3:30PM. Then today get on the hwy and shes hot. I know 160-170 is nothing to be concerned about, but why like the flick of a switch it runs so much hotter.

Groomzybanshee · May 26, 2012

Maybe your cooler is getting clogged?

Dieselboy. · May 26, 2012

Ya thats what I am thinking. What about the bypass tube ? I remember reading a while ago there is a bypass tube that can malfunction and cause this to happen. On the passenger side of the trans.

JDub · May 26, 2012

The bypass tube could fail, but I would think your temps would go much higher than 170 if that were the case.

moose99psd · May 26, 2012

The trans doesn't flow much oil without the torque converter locked, I mean it flows obviously. I figured that out the hard way trailering into a desert pit when my trans temps hit 250. I let it idle for for 45mins and it barely moved. If its an nadp trans id think they got rid of the bypass tube?

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Dieselboy. · May 26, 2012

Hmm. Dunno where to look then LOL

Moose, with the TC locked it still reaches 160-170 and even cruising on the hwy where it usually will cool it to under 120* it stays at 165ish

moose99psd · May 26, 2012

I would be looking into a clogged cooler, what's the fluid lookalike smell like?

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Dieselboy. · May 26, 2012

Fluid is pink doesnt smell burnt (less then 5000 miles on it), cooler feels cooler to touch when the trans is warm.

However I noticed a small drip of atf on the ground and crawled under. It looks like its leaking from the rear line port on the bypass tube. In that area. I wonder if something is clogged up there.

Mark Kovalsky · May 27, 2012

moose99psd said:
The trans doesn't flow much oil without the torque converter locked, I mean it flows obviously. I figured that out the hard way trailering into a desert pit when my trans temps hit 250. I let it idle for for 45mins and it barely moved. If its an nadp trans id think they got rid of the bypass tube?

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That's backwards. There is MORE flow to the cooler with the converter UNLOCKED. Flow is reduced to the cooler with the converter LOCKED.

Tampa450 · May 27, 2012

170 is hot to you?

Mine is at about 170 every day, empty.

If I hook up a trailer with anything in it, and hit some stop and go traffic, I can fairly easily hit 200.

Im in FL tho...and its HOT here!

neverkickn · May 27, 2012

Your new tunes have anything to do with it???

If it holds at 170 then I wouldnt worry. What was ambient temp when you logged the temp? If I remember right from conversation with BTS 100 degrees over ambient is normal.

TyCorr · May 27, 2012

I would.change the fluid first. Get a couple cans of cooler clean and flush the lines into a bucket. See whats in there. Blow the lines out with compressed air. Note the airflow. See whats in the bucket.If the bucket doesnt.have metal or anything large in it, use the cooler clean on the cooler. Then blow the cooler out. I hear varying.numbers but I started with 10 psi and used my left hand thumb to throttle the return fitting. Use gravity to your advantage also. You can increase air pressure but I wouldnt.use over 20lbs.

Oh and I wouldnt worry about 170°. Especially if no lines were clogged and there wasnt a bunch of.crap in the cooler. Honestly, unless the builders directions advised against it, I would have followed the breakin procedure and then changed the fluid at 3k to see what was in it.

Do trannys require breakin? Also a brand new cooling circuit totally void of trash would be near its peak of efficiency. After the trans lets some fairy dust loose into that atf the fluid would become less efficient. Not to mention it'll start blocking the coolers finer passages and you'll have a stabilized operating temp.

One more point, how are your engine temps? Have they changed lately? Like bigger injectors, bigger turbo, or different tuning? Evrything is a variable when you change the components around.

moose99psd · May 27, 2012

Mark Kovalsky said:
That's backwards. There is MORE flow to the cooler with the converter UNLOCKED. Flow is reduced to the cooler with the converter LOCKED.

Why does my trans cool better towing slow grades with the tq converter locked?

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Dieselboy. · May 27, 2012

Tampa450 said:
170 is hot to you?

Mine is at about 170 every day, empty.

If I hook up a trailer with anything in it, and hit some stop and go traffic, I can fairly easily hit 200.

Im in FL tho...and its HOT here!

No, not worried. Just curious as to why it went from 120* running temp for 8 months, then all of a sudden one day it hits 170 now.

neverkickn said:
Your new tunes have anything to do with it???

If it holds at 170 then I wouldnt worry. What was ambient temp when you logged the temp? If I remember right from conversation with BTS 100 degrees over ambient is normal.

No, I run a PCS controller. And I ran the same tune all the way home from Spokane and trans didnt hit 140.

TyCorr said:
I would.change the fluid first. Get a couple cans of cooler clean and flush the lines into a bucket. See whats in there. Blow the lines out with compressed air. Note the airflow. See whats in the bucket.If the bucket doesnt.have metal or anything large in it, use the cooler clean on the cooler. Then blow the cooler out. I hear varying.numbers but I started with 10 psi and used my left hand thumb to throttle the return fitting. Use gravity to your advantage also. You can increase air pressure but I wouldnt.use over 20lbs.

Oh and I wouldnt worry about 170°. Especially if no lines were clogged and there wasnt a bunch of.crap in the cooler. Honestly, unless the builders directions advised against it, I would have followed the breakin procedure and then changed the fluid at 3k to see what was in it.

Do trannys require breakin? Also a brand new cooling circuit totally void of trash would be near its peak of efficiency. After the trans lets some fairy dust loose into that atf the fluid would become less efficient. Not to mention it'll start blocking the coolers finer passages and you'll have a stabilized operating temp.

One more point, how are your engine temps? Have they changed lately? Like bigger injectors, bigger turbo, or different tuning? Evrything is a variable when you change the components around.

I believe NADP runs all of there trans on there "dyno" before sending them out. But it might be an idea, the trans has 3-4k miles on it as does the fluid.

Motor temps are fine, via my autometer. I will say the odd time it will hit 208 for a quick second then it comes back down to 198.

Tom S · May 27, 2012

moose99psd said:
Why does my trans cool better towing slow grades with the tq converter locked?

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I believe the unlocked converter generates heat from the movement of the fluid inside.

jngreen · May 27, 2012

I wouldn't worry about it, but keep an eye on it just in case.

My transmission guage does the same thing, I actually thought it was broken because the temps barely registered when I first installed the guage. The first time the ambient air temps went above 70 degrees, my gauge skyrocketed up to 170 or 180 degrees. Outside air temps greatly affect the temps of the transmission fluid, at least as far as where the probe is mounted.

jngreen · May 27, 2012

moose99psd said:
Why does my trans cool better towing slow grades with the tq converter locked?

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I wouldn't argue transmission tech with an ex ford transmission engineer.

Your torque converter builds more heat when unlocked, thats why it runs cooler when it is locked.