Thread: Two overdrives?
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Old 05-02-2011, 03:52 PM   #48 (permalink)
t vago
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Quote:
Originally Posted by comptiger5000 View Post
Keep in mind, his TH400 may not have had a lockup TC. In that case, it would have been slipping the TC more, making more heat. Provided you have a big tranny cooler (and you could always look into modding the valve body to increase fluid flow for cooling / lube), it should be fine.
That was part of what I was thinking, too. I was also thinking that maybe his TH400 oil pump simply was not pumping enough to properly get rid of the heat, and maybe the bands in the TH400 (I'm assuming it uses bands) were slipping from this unintended extra load.

Not sure about the oil pump in my 45RFE, but I think it can handle the flow requirements, as it is a truck transmission. It does have a lockup converter, so that heat source should not be present during cruise. The clutch packs should also stand up to the extra loading, as the 4.7L / 45RFE combination is rated at a maximum towing capacity of 6100 lbs (of course, with upgraded cooler).

I simply don't know right now. I currently have a 0.67 5th gear. If I were to remove my 545RFE computer and revert back to a 45RFE with a GV overdrive, that'd be a 0.56 overdrive.
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