Running hot...realtime help please

[landtank]

As some will know I just finished witha tranny swap. Today it seems that the truck is running hotter than I remember. I have the RavenTai mod on the guage and never really saw any fluctuations before the swap. Now it would seem to be fluctuating quite a bit. I saw the other thread by "Cary" and it might be similar to what he is seeing.

My questions are:

Can I assume that the output cooling line at the tranny is the one with the temp sensor on it.

And can I assume the flow should go from the tranny to the aux. cooler, then the radiator and then back to the tranny.

My problem is that the manual shows the hard lines on the tranny in 2 spots and they are different, 1 pic has them running side by side and the other has them crossed. They seem to fit better parallel but I'm thinking the flow is backwards that way unless I change how those pipes attach to the ones that run along the engine.

 

[Bear80]

Well I don't know which is output or input, but they do run parallel. The only cross is at the front of the engine with the rubber lines. I don't know if that helped but hopefuly it does.

 

[CJF]

And can I assume the flow should go from the tranny to the aux. cooler, then the radiator and then back to the tranny.

quote]

Hmm...

Off hand, that sounds backwards. I'm sure someone will verify.

Curtis

 

[Bear80]

AH! I just looked in the FSM and they do have a picture of the lines crossing over the bell housing. Well I'm going to change clothes and go see if I can get a better look.

 

[Bear80]

The lines never cross. The front line with the sensor becomes the top line after they come over the transmission, which at the front of the engine it becomes the line that runs under the fan shroud.

 

[Bear80]

Can I assume that the output cooling line at the tranny is the one with the temp sensor on it.

That's what I would think, you want to check the output fuild temp not the cooled input fluid.

 

[landtank]

Thanks Guys, I did find a third pic of those lines in the Engine removal section. They showed the lines side by side and how the transition hoses to the ones that run along the engine hook up.

I had it correct and the temp fluctuations must be what "Cary" saw on his truck. After a big job like this my paranoia is set on 11.

I do find it odd that the Aux Cooler is after the Rad cooler. I'd think it would be more efficient cooling in hot weather and provide a more stable operating temp in cold weather the other way around.

 

[Bear80]

Hey Rick, clean up some of your PM's.....got a question about the MM hydraulic winch.

 

[e9999]

snip
I do find it odd that the Aux Cooler is after the Rad cooler. I'd think it would be more efficient cooling in hot weather and provide a more stable operating temp in cold weather the other way around.

isn't the heat exchanger for ATF in the radiator intended to warm up the fluid when it's really cold? If so, having the external cooler be last in cold weather would negate any warming up in the main rad, no?

 

[landtank]

isn't the heat exchanger for ATF in the radiator intended to warm up the fluid when it's really cold? If so, having the external cooler be last in cold weather would negate any warming up in the main rad, no?

That's what I'm thinking, but I'm not real up to know for sure. I would think that having the rad second would provide a more constant operating temperature for the tranny.

 

[landtank]

Just got back from a camping weekend and here's the deal.

On the drive out it was 82* and ran in the red the whole way out.
It was 100* today and ran in the red the entire 2 hour trip back.

While out there I replaced the t-stat. Without towing 4k behind me it runs 2 needle widths above normal in 100* heat.

I have RavenTais guage mod and can tell you that the AC cuts out when the needle's center is on the lower edge of the red. So I wasn't incredably hot just over the AC cut out.

Anyone heard of a tranny over heating an engine?

I'm thinking of bypassing the Radiator cooler with the tranny lines to see if that had any effect.

I don't want to go crazy here because without the Guage mod I doubt it would have been noticable that I was running hot.

 

[RavenTai]

Ouch,


are you sure the torque converter is locking up on the new transmission?

 

[landtank]

are you sure the torque converter is locking up on the new transmission?

The best I can tell it is. While on the highway doing 65mph I'd depress the accelerator and see the rpm jump a little and then shut of OD and get a shift change.

Is there a better way to tell?

 

[landtank]

If somebody wouldn't mind, could you get an idea of how warm the Aux cooler for the tranny is after the truck has been run for a while. Mine is too hot to touch and I don't remember it ever being that way.

 

[RavenTai]

I have had domestic vehicles where TC lockup felt like a shift into a 5th gear that the trans did not have, you could really feel the lockup, with the A343F the TC lockup is pretty soft you really have to watch the tach to find lockup.

IIRC the to0rque converter is looking for more than just being in 4th gear (OD), I think there is a speed and load logic part to it. But I may be getting confused with the AW4 I have been helping a friend on lately (AW4 is in the same family as the A343F), the exact condition for lockup should be somewhere in the manuals, I’ll look later but for now this should get you in the ball park:

when doing a highway speed (>50MPH IIRC) open the throttle more but to not go to WOT, and do not make it down shift, the RPM should slowly move up as speed increases same as it would with a manual transmission, if there is an instant 200 or so RPM increase (slop) then it is unlocked,

You can do the same with deceleration but slightly different, when cruising at highway speed let off the gas fully to the idle stop, the RPM will hang for a moment and then drop, the TC will unlock when the TPS says you are throttle closed but it takes a second or so, that is that momentary hang in RPM.

Do these at below 40 and above 60 and you should be able to notice a difference, you may also catch an RPM change right around 50MPH or so.

the only reason I jumped to this is that if the TC is not locking up the transmission will make more heat, being the problem came on when you changed transmissions it could be, but then it could be a wild goose chase,

Temporarily bypassing the rad cooler might be a good trouble shooting aid, the trans cooler is still up the air stream form the rad so an overheating trans will still have some effect but should not be as direct.

BTW thanks for reporting the AC cutout at bottom of red,

Was this when it cut out or when it came back on?

Supposedly it is suppose to cut out on the way up at 226 and come back on at 217 on the way down.

It funny I started with the idea of a 226 bottom of red and at the last minute changed it to 217, if you got 226 at bottom of red then it came out as originally intended anyway.

 

[landtank]

I'm pretty sure the TC is locking up.

As for the AC cut off it was on the way down. I was idling in a rest area and kept switching the AC of and on looking for the idleup when it was engaged. So it looks like you got it right at 217.

The issue is that this is the first summer with the modded guage so I can't relate what I'm seeing with the past.

 

[RavenTai]

yes this the first summer for the temp gauge but I think you would have noticed AC cutting out last summer, what were the conditions for the AC cutout jsut idle but OK under way?

for comparison here in 90-100 degree weather mine climbs up at idle with the AC on but has not gone much further than half way to the red from the middle, maybe a little more. under way mine heads back to the middle.

what temperatures and conditions are you getting "to hot to hold" with the aux cooler? I need to go get dinner but being early summer we still have cool nights, out there right now (upper 70's? ) and I am not towing anything.

 

[Rich]

there a better way to tell [if the torque converter is locking up]?

Well, here is how you can determine if the torque converter clutch will lock up in 3rd gear. Drive up a hill steep enough that the transmission downshifts from 4th into 3rd. After it downshifts into 3rd hit the overdrive button to lock out 4th. The torque convert clutch should then lockup in 3rd and your rpms should drop with the lockup.

You may wish to invest in a tranny temp gauge and see whats going on there. Or invest in an obd II scanner that can monitor tranny temp live.

I've only had my AC cutout in outside temps well over 100° F, fully loaded, with the accelerator floored climbing desert mountain passes.

 

[CJF]

On the drive out it was 82* and ran in the red the whole way out.
It was 100* today and ran in the red the entire 2 hour trip back.

WTF???

I'm doubting what I'm reading here; you ran your 1FZE for multiple hours with the engine coolant gauge in the red???



Curtis

 

[Erratic]

Will an obd2 reader read tranny temp? I just plugged in my snap on MT2500 and it did not give a tranny temp?! I was like WTF. I think it should. Does the tranny have a factory temp sensor?