[rsnider]

Re: WOT in a 4R70W. I thought I might try the Movaje Mile or the Texas mile with my auto Mach 1 but the speed shop said NO! They claimed the trans won't hold up under WOT. It thought I'd go straight to the source to I emailed a close friend who works at Roush but is retired from Ford Driveline. This is his response with names and numbers deleted. This only concerns WOT and not a 3-4 shift at WOT. Start at the bottom.


XXXXXXXXXX
Powertrain Engineering
Roush Industries
313-XXX-XXXX

Yep,
4R70 and 4R75 are mechanically identical but some components are of higher torque capacity.
Tell your friend to enjoy his drive
XX


On Tue, Aug 23, 2011 at 2:14 PM, XXXXXXXXX

XXX, thanks for the info. Assuming that 4R75=4R70 for this discussion. I'm just not as familiar with the badging.
Regards,

XXXXXXXX
Powertrain Engineering
Roush Industries
313-XXX-XXXX


Hi XXXXX,
the "never" drive at WOT in OD is a carryover concern from "WAY BACK WHEN" at the beginning when 4R75 was called AOD, and it had a lube issue for the gear set - that was corrected and doubly verified to be cured (multiple times) each time a new manager showed up and had heard the same concern. When XXXX XXXX was the manager, XXXX XXXXX was also concerned and they convinced themselves (and the rest of Ford ATEO) that there was indeed NO issue with running at high speed in 4th gear.
Just do NOT downshift to 2nd gear at high speed from 4th - this manuver will indeed cause major damage (this was a calibration error by a hard-headed calibrator who insisted on not allowing a downshift at high speed, despite the fact that the OWC would self destruct) - no I won't tell you who he was, but I'll bet you do know him.
BOTTOM LINE
It's OK to drive high speed in 4th.
Take care,
XXX


On Tue, Aug 23, 2011 at 12:38 PM, XXXXXXXXXXXX

Hi XXX, enjoy receiving the snippets. I forward them on to my brother in Winchester Tn. who has a plastics business that supplies into the industry.
How is your son doing?
A friend of mine has a 2003 Mustang with a 4.6L and subject trans. He had a performance shop do some work on the trans and put in a high rpm stall convertor. He was advised (with emphasis) to NEVER drive wide open in overdrive. The shop said the overdrive was meant for expressway cruising not max speed runs.
My friend would love to see what the top end of his car would be but fears going any faster than 3rd gear allows.
Is this an issue with the 4R that your aware of from your days in trans?
Thanks.
Regards,