J mod/Performance Automatic Valve body issue - 2003-04 Mach 1 Registry Owners Club

GR8 WYT · 10-12-2011, 08:42 PM

I realize this is for the 4r70w...and the automatic Mach 1 had a beefed up 4r75w...but I need help.

I put the Performance Automatic valve body upgrade in my son's 03 GT 4r70w trans. Replaced accumulator springs, etc.

Everything is great, but now we are seeing an issue when crusing with overdrive ON.

When you go to accelerate, the revs jump and it does not down shift. Seems to be getting worse with time.

I did find a thread about needing to re-torque the valve body attaching bolts as they come loose due to the thick gasket on the valve body.

Anyone else have any experience with the J mod on the 4r70w or the Performance Automatic valve body doing the same thing??

Thank god I put on a deep sump alum finned trans pan with a drain plug. The thought of doing this again on my back under the car on jack stands does not thrill me.

Thanks in advance.

GR8 WYT · 10-13-2011, 06:25 PM

Followup:

Drained the pan, dropped it, and re-torqued the valve body screws to 10 ft lb.

It fixed the problem. Keep this in mind if you EVER mess with the valve body on a Ford 4r70w. Making sure those bolts stay tight is crucial.

10-12-2011, 08:42 PM	#1
GR8 WYT Registered User Join Date: Aug 2002 Location: Hughesville, Maryland Posts: 594	J mod/Performance Automatic Valve body issue I realize this is for the 4r70w...and the automatic Mach 1 had a beefed up 4r75w...but I need help. I put the Performance Automatic valve body upgrade in my son's 03 GT 4r70w trans. Replaced accumulator springs, etc. Everything is great, but now we are seeing an issue when crusing with overdrive ON. When you go to accelerate, the revs jump and it does not down shift. Seems to be getting worse with time. I did find a thread about needing to re-torque the valve body attaching bolts as they come loose due to the thick gasket on the valve body. Anyone else have any experience with the J mod on the 4r70w or the Performance Automatic valve body doing the same thing?? Thank god I put on a deep sump alum finned trans pan with a drain plug. The thought of doing this again on my back under the car on jack stands does not thrill me. Thanks in advance. __________________ Aluminator NA bottom end, rebuilt stock heads, Vortech V2, 3.90 gear, 514 RWHP, 468 RWTQ. Motor and tune by JPC. (Millersville, MD)

10-13-2011, 06:25 PM	#2
GR8 WYT Registered User Join Date: Aug 2002 Location: Hughesville, Maryland Posts: 594	Re: J mod/Performance Automatic Valve body issue Followup: Drained the pan, dropped it, and re-torqued the valve body screws to 10 ft lb. It fixed the problem. Keep this in mind if you EVER mess with the valve body on a Ford 4r70w. Making sure those bolts stay tight is crucial. __________________ Aluminator NA bottom end, rebuilt stock heads, Vortech V2, 3.90 gear, 514 RWHP, 468 RWTQ. Motor and tune by JPC. (Millersville, MD)

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