Description
AODE / 4R70W Oversized Pressure Regulator & Boost Valve Kit, Sonnax 76948-16K.
Fits ’95-earlier only.
Tooling:
- F-76948-TL
- 76948-TL4
- 76948-BST
- VB-FIX
Common complaints in vehicles with Ford AODE and 4R70W transmissions is low line pressure resulting or band and/or clutch failure, or throttle-sensitive buzz, especially when hot. These issues can be caused by severe wear at the outboard pressure regulator valve spool or bore area. Wear at this location allows EPC oil to leak to exhaust, resulting in poor line rise. As oil temperature increases it becomes less viscous and more leakage occurs. Wear at the inboard balance spool bore is also very common, which can result in excessively high lie pressure that can damage the case. Sonnax oversized pressure regulator valve and boost valve kit 76948-16K restores valve-to-bore clearances so the pressure regulator valve can maintain correct pressures.
- Improved PR/EPC reaction area ratio provides higher line rise response to EPC pressure, which results in noticeably firmer shifts
- Hardcoat anodized aluminum valve combats premature wear
- Annular grooves added to pressure regulator valve prevent side loading wear
There are two reaming options available for this kit:
- Reaming Option 1: Tool Kit F-76948-TL. This option includes reamer, reamer jig and guide. It requires reaming fixture VB-FIX but not bore sizing tool.
- Reaming Option 2: Tool Kit 76948-TL4. This is a bench tool kit and does not require VB-FIX. After reaming with bench tool kit, use Bore Sizing Tool 76948-BST (sold separately) to provide exact sizing and improved bore finish.
Either tool kit works for all model years.
- Pressure Regulator Valve
- Reverse Boost Valve
- Reverse Boost Sleeve
Symptoms:
- Uncontrolled pressure in Reverse
- Soft shifts
- Delayed Reverse
- Low line rise
- Throttle buzz
- Erratic Reverse pressure
- Clutch failure
- Band failure
- Damaged case
Cause:
Wear at the pressure regulator valve bore and reverse boost sleeve allows valuable EPC, line pressure and reverse boost to exhaust.
Correction:
Sonnax oversized pressure regulator and boost valve kit restores correct clearances for proper hydraulic control, and a replacement reverse boost valve assembly.
Warning:
The oversized reverse boost valve and sleeve supplied in these kits must be used when replacing the PR valve.
