Oil and coolant temps while towing heavy Zf6 vs 4r100

ClassicIDI

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ok this is a long drawn out saga of mine but im really looking for what you guys are seeing when towing.

I have 3 trucks

#1 early 99 swamps reman AD injectors, adrenaline, s364 billet wheel (Aurora 4k) out of the box php hydra tuning, 4:30 gears, 35" tires, built auto trans with 6.0 cooler, ATS intercooler 350K on the truck

#2 Early 99 stock auto trans with 6.0 cooler. bone stock except for exhaust and superchips tow tune, 3.73 gears 32" tires and that's it 164K (dad bought new)

#3 Early 99 ZF6 bone stock except for 4" exhaust. no tunes 3.73 gears 32" tires 210K


My trailer is 40ft enclosed triple axle that I put two crawlers in and tow all over the country. I'm in denver and tow the mountains alot trailer weights 22K loaded so with truck im pushing 30k Its heavy.......

I have been towing this trailer with truck #1 for 4 years and its been a challenge. always fighting oil and coolant temps egt's are never an issue. but pulling passes I will see 230-240 coolant and 245-255 oil temps and much higher if i push the truck hard. EGT's normally not an issue unless I mash the pedal then they will climb.

Last year I was on a trip and lost the #7 cylinder in kansas city (truck #1). On a whim I bought truck #3 and proceed on my way. This truck is an entirely different truck, cant get it hot even If I try. oil temps are maxed at 230 no matter what. Coolant temps 220 no matter what. egts laugh at 1200 degrees. and truck tows the trailer just as fast if not faster then then the old one.

I thought it was because of the non stock parts on #1 so yesterday I hook this same trailer to Truck #2 and proceed into the mountains. Oil and coolant temps hot. 257 oil temp, gauge on dash starts to climb so 235 coolant, egts ok at 1000-1100 but im in 1st doing 20mph. truck is struggling. pull the first hill turn around and go home hook up truck #3 so same hill same trailer same day. this pull is 5-7% grade and 10 miles long

Truck sees oil temp 234, half way up I down shift to second and temps start to cool off to 230.. dash gauge never moves and im doing 15-20mph faster then #2. egts 900-1000.

Is this all because of the zf6? This is the only zf6 truck Ive had This truck has some rust and I hate rust but otherwise its a fantastic truck. My plan was to keep #2 and put a BTS in it but now IDK. Im trying to figure out if its worth converting #2 to a zf6. #2 is a cream puff garaged perfect condition truck my dad bought new but struggles to pull this trailer.

Is truck #3 a normal zf6 truck or some kind of unicorn that if i sell i'll regret forever? How can just a zf6 make the truck run so much cooler and faster?

If i convert #2 to a zf can I expect the same performance from it?

truck #1 and #2 tow very similar temp and speed wise.

those of you with zf6 trucks what temps do you see towing heavy?

thanks for hanging in there with me
 

ClassicIDI

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All three trucks are early 99 so no trans cooler in rad. Both autos have 6.0 coolers and the trans in both run cool.

I agree more power = more heat. #1 used to have 300/200 and gen 3....that didn't last long with this heavy ass trailer. Quickly realized all that power was useless without a radiator the size of a refigerator.

I'm past my quest for power. I just want reliable, And completely ok doing 20mph but not with oil temps in the 250's

I push that zf6 Truck way harder and it pulls 35-40mph with 30 degree cooler temps.

I'm just trying to understand how and why. It out pulls all my friends trucks as well with a heavier trailer. Bullet proofed 6.0 auto, another 7.3 with a BTS and an 05 Cummins auto. This stock zf6 truck just seems magical....

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ford_trck

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I've never monitored oil and coolant temps beside factory gauges. But my early 99 truck stock (ZF6) would barley walk my 02 with an auto. It use to be the Manuel trucks had a little more power than the auto trucks at the flywheel and they obviously have less power loss than an automatic would have. I love my 6 speed and wouldn't trade it, I've had it for 10 years.
 

BS Hauler

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I have an 02 6sp and a 6.0 auto. I have a big horse trailer and it is about 16,000# loaded. I will take the manual trans every time over the auto. My temps are about the same with both trucks. The manual just seems to be more efficient in power transfer.
 

psduser1

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Are the radiators in similar condition? Water pumps in similar condition?
The auto will have a little more load- easily 10% more, and maybe more, depending on condition.
 

ClassicIDI

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Yep all rads are clean. Water pump on #1 has 30k, #2 has 100k and no idea on #3, since I bought it last year. I have personally pulled the rads in the autos and cleaned them so I know they are free of debris. #1 has elc coolant #2 & 3 are just green.

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griz700rocket

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Love my 6 speed. Just wish 4th/5th were a little further apart in gearing.

Possible problem with fan clutch?
 
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ClassicIDI

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#1 has a brand new clutch and tensioner. The clutch on #2 and #3 both kicked on within half a mile of the same point on that pull and stayed on till the top just #3 maintained temps while #2 would've over heated badly had I not driven according

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co04cobra

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IMO. It's somewhat simple physics. The manual is more efficient at transferring the power to the ground.

In a "nutshell" the auto causes the engine to work harder while actually putting less power to the ground to do the work.


Now year differences come into play also, as far as actual power output goes per truck.


A E99 truck and 02 truck can have almost a 50hp rating difference from the factory.


Now with modified injectors and/or turbo selection the efficiency of the setup changes drastically. Tuning comes into play huge in those scenarios.
 
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ClassicIDI

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Well I've located a perfect zf6 donor truck and going to buy it Saturday. I really didn't wanna do all this work and was hoping I'd get away with a BTS but I can't ignore the numbers towing this trailer. I've been driving this zf6 truck a year now and I like it.

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