5R55E overheating in 4hi while under load???

[manaen]

you don't have mud clogging your radiator do you? be sure there is good airflow from the fan

 

[Boomer12]

Yes, there is adequate flow on the return side...and no, there is not any extra impedance of airflow to the radiator...

...and thank you, for your patience/assistance.

 

[manaen]

OK then if there is fluid flowing through the coolers and air flowing then that eliminates issues with the internal cooler bypass, fluid & air flow issues.

I guess that leaves slippage issues.


are you driving in 1st gear or D when doing this, and is the tranny shifting a lot?

 

[Boomer12]

Solely in 1st gear (speed: crawling-15 mph).

 

[manaen]

I would check line and EPC pressure to make sure they are within spec

 

[manaen]

When my EPC was gettign tired I notice excessive heat too, once I Installed the transgo kit and all the ford updates with a new EPC and cooler, the heat never rises above 198 and that was on the hottest day (about 99deg) climbing a mountain with my 4500lb camper in tow. Before the updates I couldn't pull out on the highway with my camper without it slipping and heating up to over 200.

 

[Boomer12]

Thank you again, and I will look into those additions as soon as money permits...

 

[manaen]

do the shifts seem to be excessively soft?

 

[Lefy]

If they put a tube style in it could have actually reduced your cooling.

This is what I have on my trans the tube one inline with the stock cooler and was wondering why it would reduce the cooling :scratch:

thanks for the info

 

[Boomer12]

It still shifts alright, nice and solid...other than this little problem, I would have never known anything was wrong.

 

[manaen]

This is what I have on my trans the tube one inline with the stock cooler and was wondering why it would reduce the cooling :scratch:

thanks for the info

because he said they replaced the stock cooler with the after market one. And due to the fact that the stacked plate coole is SO much more effiecient at cooling the fluid. So the smaller stock cooler could actually be better then a larger tube style cooler. That and the SP coolers flow much better then tube coolers.


If you retained the factory cooling and added a tube cooler your ok, but just know that a SP cooler of the same size would reduce the temps quite a bit over the tube cooler.

Oh there is one other benifit of the SP cooler they hold more fluid.

 

[manaen]

It still shifts alright, nice and solid...other than this little problem, I would have never known anything was wrong.

I wondering if there is still a problem with the cooler bypass in the transmission, maybe it is not properly diverting the fluid into the coolers when it needs to. I know you checked flow, but when my tranny starts to heatup I have about 40psi of fluid flowing through the lines (checked at my external filter). What if the transmission was never really opening the thermostat properly.

We need Glacier to chime in on that one, I don't have the knoweldge of the inner workings of the cooler bypass built into the 5r55e transmission. Actually this scenario is why I decided it would be a good idea to add a psi gauge to my external filter in the first place. That way I know there is good flow through the lines.

I'll break out the ATSG manual and see what I can find

 

[Boomer12]

Again, many thanks...

 

[Boomer12]

So I took it back out today, and somehow manged to sweet talk it into 4lo.
It worked great, with no threat of overheating...leads me to believe that it's less of a cooling problem, and more of a gearing one. It just creates to much work, and the cooler can't keep up...

By no means am I trying to claim victory...but I can rest a little easier.

Thank you once again for your help...

 

[gijoecam]

I was going to suggest simply using 4low all along, but didn't want to get ridiculed for the idea... 1st gear, drive at 15mph generates very little cooling air over the trans cooler, and the high stress on the trans generates a TON of heat (torque converter slippage) Using low range under those conditions alleviates a TON of stress (and heat-generating torque converter slippage) on the trans and lets it run cooler. It also ups the speed of the trans and, likely increases the flow rate of the fluid to the cooler.

15mph crawling is prime time for low range.

Another thing: What ratio of coolant to antifreeze are you running? If you run more water in it, as high as 70/30, you tremendously increase the oil to water heat exchanger's ability to wick the heat out of the oil and dissipate it to the atmosphere. Just something to consider.