Compression Ignition Addict
Join Date: Oct 2006
Location: Walpole, MA
Thanked 24 Times in 23 Posts
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Dumb me up a little..I know engines,but not trannys,fill my small cranium!!!
Can you tell me what I need to know?...always want to learn more!!
Thanks in advance!!
Well, what do you wan to know? I am by no means a trans guru.
As far as the bypass on the 4R100 the theory behind it is that it is a pressure bypass that in the case of a complete blockage in the cooler line and trans pressure exceeds a certain amount the bypass will trip and allow uncool fluid to return the trans and allow the user to limp home instead of a complete destruction of the trans.
The big issue with them is sometimes they get stuck open when there isn't a blockage causing excessive transmission temps. Some trans builders delete them, some don't. Personally I have not touched mine cause in about 300k of driving trucks with 4r100s (between two trucks) I have never had an issue with so if it ain't broke.
The temps you mention seem a bit high so your bypass could be stuck open or there could be other issues. The 6.0 cooler makes a huge difference, with 45* air temps in Boston bumper to bumper traffic and my winter front totally closed my trans never got over 125*.
2002 F-350 4X4 ECLB 7.3 4R100 6637 filter w/ RiffRaff cover, 08 diff cover, 203* T-stat, HPX, Stancor Relay, 6.0 trans cooler, Zone leveling kit, 8'6" Western Ultramount
Sold: 04.5 Dodge Ram 2500 5.9 CTD, Reg Cab, 48re