8hp70 heater bypass

[MRFREEZE57]

Same, I ran out of jack. The bubble on my level was just within the lines, figured it was close enough.

I used a set of auto ramps and had to use an additional 6 inches of shim under the tires, checked the pan with a tape measure at front and back, was within 1/8 inch.

 

[tfeni52355]

I used a set of auto ramps and had to use an additional 6 inches of shim under the tires, checked the pan with a tape measure at front and back, was within 1/8 inch.

I like the idea of using the ramps. Lots of solid surface under both wheels.

I scavenged some LVL beam scraps from the new homes they are building in my area. Put them under the floor jack and the safety stands to get me reasonably close to level. I used wheel chocks at the front wheels as well. Not too crazy about going under the truck without safety stands or some solid surface to support the truck like the ramps.

 

[Wild one]

I like the idea of using the ramps. Lots of solid surface under both wheels.

I scavenged some LVL beam scraps from the new homes they are building in my area. Put them under the floor jack and the safety stands to get me reasonably close to level. I used wheel chocks at the front wheels as well. Not too crazy about going under the truck without safety stands or some solid surface to support the truck like the ramps.

The tires need to be in the air,so the transmission can shift into 2nd gear. It needs to shift into 2nd to fill the clutch circuits is my understanding.

 

[RAMTRPR]

Any type of thermal bypass for the 545RFE?

 

[caulk04]

The RFE doesn't have a heater and I'm not certain it has a thermostat of any kind.

 

[BlownGP]

Any type of thermal bypass for the 545RFE?

Don't need one really. Get a 180 thermostat, Wrap the crossover pipe and get 4x4 deeper pan or PPE deep pan.

Like Caulk said, there's not heater or thermostat on the RFE

The highest my 09 got was 170. Now towing it might get hotter but never towed anything heavy with my truck.

 

[Wild one]

Don't need one really. Get a 180 thermostat, Wrap the crossover pipe and get 4x4 deeper pan or PPE deep pan.

Like Caulk said, there's not heater or thermostat on the RFE

The highest my 09 got was 170. Now towing it might get hotter but never towed anything heavy with my truck.

Starting in 13 when they adopted the Thermel Management end of things,some of the RFE's got a thermostat.It's a square block of aluminium behind the grill on the pass side of the truck.There is a delete kit for it,or you can do like i did on my old 13,long before there was a delete kit ,and remove the thermostats block and tie the lines together.

 

[HEMIMANN]

Starting in 13 when they adopted the Thermel Management end of things,some of the RFE's got a thermostat.It's a square block of aluminium behind the grill on the pass side of the truck.There is a delete kit for it,or you can do like i did on my old 13,long before there was a delete kit ,and remove the thermostats block and tie the lines together.

I like the delete kits better because they drill thru the full diameter oil line - not the tiny orifice restriction hole for the tiny thermostat. Costs only $100 and some elbow grease and special tools. But then it's done forever @ full oil flow, as it was originally designed for.

 

[Evguy1]

This has been an interesting 33 page read. I wanted to read the whole thing to see if anyone had a bad experience by running colder trans fluid. I'm doing an engine swap and was not going to reinstall the heater, lines and valve. I also needed to replace the trans cooler lines as they don't work with my new engine. Talked to one of the ZF8HP70 gurus and he said to just pull the cooler/heater unit off the trans and tap the trans for AN8 fittings. I had everything set to go and was actually sitting up under the truck with my tap in hand and wondered what happens if you just gut the old T stat housing and run new lines off the top of it. I gutted the housing, tapped (1/8" NPT) and plugged the old holes that went to the heater unit and found that the stock lines actually use a ORB style fitting/adapter to connect to the hard lines. I just replaced them with AN8 adapters and can now run new rubber lines up to the front. It can all go back to stock if need be. Here is the housing after modifications.

 

[HuskerRam]

Has anyone towed with caulk04's mod? If so, what kind of temps were seen? Does it still get to 215-ish when taxed?

 

[Wild one]

Has anyone towed with caulk04's mod? If so, what kind of temps were seen? Does it still get to 215-ish when taxed?

I don't tow with mine,but i do drag race the truck. I used to see 200+ tranny temps on a nitrous pass,last week-end i ran several back to back passes,and the highest i seen was 148 and that was after 3 back to back passes with the out door temp being in the mid 80's.

 

[crazykid1994]

This has been an interesting 33 page read. I wanted to read the whole thing to see if anyone had a bad experience by running colder trans fluid. I'm doing an engine swap and was not going to reinstall the heater, lines and valve. I also needed to replace the trans cooler lines as they don't work with my new engine. Talked to one of the ZF8HP70 gurus and he said to just pull the cooler/heater unit off the trans and tap the trans for AN8 fittings. I had everything set to go and was actually sitting up under the truck with my tap in hand and wondered what happens if you just gut the old T stat housing and run new lines off the top of it. I gutted the housing, tapped (1/8" NPT) and plugged the old holes that went to the heater unit and found that the stock lines actually use a ORB style fitting/adapter to connect to the hard lines. I just replaced them with AN8 adapters and can now run new rubber lines up to the front. It can all go back to stock if need be. Here is the housing after modifications.View attachment 468265

-8an orb fittings? Hell yea. I was thinking about doing a full separate trans cooler in the future and possibly moving it to under the bed or in the front bumper and installing an inline thermal bypass unit so that would make it so much easier to do what I want.

 

[Evguy1]

That was what I was thinking, adding the thermal bypass was high on my list since we get a few weeks of freezing in the winter. I also have a couple of the high flow trans coolers with fans that I was thinking about adding under the bed. I'll start with the stock cooler and see how it goes for towing. The sole purpose of this truck is to tow our 5th wheel. The nice part of JIC is I can just use off the shelf hydraulic hoses.

 

[HuskerRam]

I don't tow with mine,but i do drag race the truck. I used to see 200+ tranny temps on a nitrous pass,last week-end i ran several back to back passes,and the highest i seen was 148 and that was after 3 back to back passes with the out door temp being in the mid 80's.

That‘s good info…thanks!

 

[Wild one]

That was what I was thinking, adding the thermal bypass was high on my list since we get a few weeks of freezing in the winter. I also have a couple of the high flow trans coolers with fans that I was thinking about adding under the bed. I'll start with the stock cooler and see how it goes for towing. The sole purpose of this truck is to tow our 5th wheel. The nice part of JIC is I can just use off the shelf hydraulic hoses.

High-Flow Engine & Transmission Oil Cooler Thermostat

Improved Racing's Flow Series Motor Sport (FSM) oil thermostat is a universal solution that can be used with any oil cooler on any vehicle or industrial application flowing up to 20 GPM (75.71 LPM). Trusted by professional race teams, OEM's, and military contractors. Accelerates fluid warmup...

www.improvedracing.com

 

[Evguy1]

Got the new trany lines today. They are 3500 PSI hydraulic lines so they should last a while. :>)

 

[HEMIMANN]

I'll just leave this here. Some light reading for the interested.......

Temperature Stability of Lubricants and Hydraulic Fluids

Fluid temperature stability is essential to the success of mechanical systems. All hydraulic and lubricating fluids have practical limits on the acceptable operating temperature range - both…

www.machinerylubrication.com

"Fluid temperature grossly affects chemical stability and particularly the oxidation rate of the basic elements of the oil. The primary accelerator of all oxidation reactions is temperature. Like any other reaction, the oxidation rate of hydrocarbons will approximately double for every 18 degrees Fahrenheit increase in temperature.

Below 140°F, the reaction is comparatively slow, but engineers estimate that the life of an oil is reduced 50 percent for every 18 degrees Fahrenheit temperature rise above 140°F, according to the Arrhenius equation for chemical reaction rates. Hence, for high-temperature applications, the oxidation stability of an oil can have great significance and users should assess it carefully."

 

[caulk04]

Not hot outside, but towing my RZR down the highway yesterday. Load of ~3k, lots of hills as you can tell by the oil temps. Still haven't hit 160 on the trans. Only changes from stock are grille shutters removed and my bypass valve.

 

[MRFREEZE57]

View attachment 469309

Not hot outside, but towing my RZR down the highway yesterday. Load of ~3k, lots of hills as you can tell by the oil temps. Still haven't hit 160 on the trans. Only changes from stock are grille shutters removed and my bypass valve.

Caulk,
do you think removing the shutters helps? I have your replacement valve in my truck, great improvement on temp, before would go to 185 in traffic, now will sometimes hit up to 160 deg when in traffic but much better than before, will removing the shutters help in this case?

 

[caulk04]

It might help. I do have mine pulled for the summer and will likely put them back in this winter, it gets plenty cold here plus it probably helps keep some road spray out of the engine compartment