CK5
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Crew cab. Use it or lose it.

For that price you could rig up a ridiculous cooler setup that circulates the gear oil.
 
When I was working at the General they were putting rear diff coolers on the high HP V model CTS's. They were driven off the rear driveshaft IIRC, I always thought that would be an efficient way to circulate fluid like this and take the load off the charging system and rid oneself of an needed wiring. When the vehicle is moving its on when its not its off.....simple
....Just a thought anyway.
Jason
 
Mike has it pretty much layed out.

12v oil pump but I'd operate that with temp switch, just an on/off switch. That way it can run only when needed allowing the trans to reach a good running temp before it starts circulating the gear oil. Run some lines up front and pass them through a filter then a cooler and back into the PTO cover.

I had thought about doing it off of the driveshaft. Just seems like a lot of headache.
 
Put right at 1400 miles on the crewcab this weekend. I'd say any cooling issues have been straightened out. Engine ran great the entire time.

The transmission still gets hot. Only when pushing it hard and into the head wind. Ambient temps went up and with the head wind, we were working it pretty hard. Once it gets warm you have to pump the clutch to get full disengagement. I think some heat soaks into the slave cylinder and causes some issues. Just a theory.

Bias ply tires really sock! That will soon be rectified.
 
I haven't been under the truck since we pulled the TH400 out of it, so forgive me if this is a dumb question...

Any chance the header could be heat-soaking the slave? Increased load = increased EGT's.

Also, what fluid is in that system? You could give some 5.1 a try. Still glycol but increased resistance to heat.
 
I don't think the exhaust is close enough to heak soak the slave. There is one place the line is close and could be an issue. It would be nice to go to a steel line just to get rid of any possible line stretch or swell.

Figured the mileage at the beginning of the trip at 8. After the first top off, I pulled the visor off the truck to test the theory of it sucking up MPG's and I have to say I believe it made a difference. 1 mpg at best but its there and measureable. Visor is staying off.
 
You're now getting just slightly worse mileage than I am...with two more tires, 85 more gallons of fuel, and twice the cab.
 
You're now getting just slightly worse mileage than I am...with two more tires, 85 more gallons of fuel, and twice the cab.


For what it is, the numbers are pretty respectable. I think with the gear swap and radials, it'll get better.
 
I had 2 old broncos. (1) 78 and (1) 79. the 78 had a visor on it. both trucks were running 33" tires.

the 78 with the visor was always 1.5 mpg less then the 79
 
Sounds like you have an external slave? Does it have that wonderful plastic line on it? Steel as you suggested would be a lot better for dissipating heat from the fluid, or better yet (for heat dissipation anyway) would be some of the aluminum line some racers use. Of course thinking aloud now, if you did have an external source inducing heat into the fluid the plastic would have an insulating factor over the steel or aluminum.
JLT
 
It is an external slave cylinder.

The line is braided high pressure AN type line. Seemed like the obvious choice at the time.

I had just done a bunch of work with that type of line and enjoyed working with it. It's rated for the pressures and one of the suggested uses is hydraulic clutches. I think if it were to get too hot, it would fail where as regular steel line would not. Either way, the fluid inside would still be affected by the heat.

Whatever it is, there is most certainly an element of heat involved that directly causes some issues with the clutch pedals ability to disengage the clutch. Both the master and slave are new units. Both in normal places not any closer to heat sources than they would be in any other application.

I may try a longer line and take it forward around the engine block up front rather than around the back where the header heat is higher and closer.
 
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