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Is anyone running this set up? Have you towed heavy? I have a 350 drw 4x4 that I thought this would be great for if it worked and held up. The truck has 4.10s now and my plan would be drop the ratio to 4.88 maybe even 5.13 and with the gear vendors od at .55 I would actually have a higher top end than I do now along with a stupidly low first gear. Any thoughts ?
 

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A GV (or any external overdrive) will absolutely destroy a 4R100. Ask me how I know. Not just "a little noise" but spectacular failures with blue-tinted parts scattered down the road.

4R100s are derived from car transmissions and utterly depend on their torque converters to pump tranny fluid through the cooler. Without adequate fluid flow heat builds up. Blued metal is the dead giveaway. A bigger tranny cooler has no effect on this as the fluid flow is limited by the torque converter RPM. Diesels are high-torque/low RPM engines. Allisons are designed from the git-go for low-RPM operations. Nothing else prior to 2011 are so designed.

You can probably find an old school bus with a 7.3 (nee International 444) out there. There were thousands of these thing prowling the road hauling the little darlings to school every day. Not heavy loads, but nothing but stop-and-go. This is a very rigorous duty cycle.
 

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Former Ford Trans Engr.
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A GV (or any external overdrive) will absolutely destroy a 4R100. Ask me how I know. Not just "a little noise" but spectacular failures with blue-tinted parts scattered down the road.
I have no doubt that you had a spectacular failure. But the rest of this post is full of bad information.

4R100s are derived from car transmissions
Not true. The 4R100/E4OD was derived from the C6. That was a truck transmission that was used in some larger cars.

and utterly depend on their torque converters to pump tranny fluid through the cooler.
Absolutely false. The pump pumps fluid through the torque converter and through the cooler. The pump has adequate flow to maintain pressures and flow anytime RPM is over 1300 RPM. If you have an additional overdrive so that you are running for a long time at less than 1300 RPM you could have a problem.
 

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Project Shamu
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I have no doubt that you had a spectacular failure. But the rest of this post is full of bad information.


Not true. The 4R100/E4OD was derived from the C6. That was a truck transmission that was used in some larger cars.


Absolutely false. The pump pumps fluid through the torque converter and through the cooler. The pump has adequate flow to maintain pressures and flow anytime RPM is over 1300 RPM. If you have an additional overdrive so that you are running for a long time at less than 1300 RPM you could have a problem.
You know, I was going to bring that up, because I notice with my 3.73s and 35s, at 55mph I'm at 1400rpms. That couldn't mean I was killing my trans! Everybody who drove at 55-60mph with 35s, 37s, or bigger, on stock gears, would be cooking trans' left and right. I couldn't imagine with the more common 3.55s

Granted people already do, but I dont think from lack of fluid flow.
 

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If it ain't heat buildup, how do you explain blue steel parts?

Basic heat transfer equation: Heat Flow = Mass Flow rate x specific heat of fluid x temperature differential.

It ain't voodoo. Just engineering fundamentals.
 
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