Watch Out for 4R70W Pressure Regulator Valve & Casting Wear

It’s common for the pressure regulator valve in Ford 4R70W, 4R70E, 4R75W, 4R75E and AODE units to experience severe wear. Scoring on the EPC end of the valve (Figure 1) is typically quite noticeable and will result in reduced line pressure or low line rise concerns.

Figure 1 – Worn 4R70W PR Valve

When you see damage like this, it can be tempting to just replace the valve. If the valve is in this bad of shape however, it's a good bet that the bore has been compromised as well. A worn casting will not allow for proper sealing even with a new valve installed.

As bore wear is often difficult to see with the naked eye, vacuum testing will reveal that it needs to be reconditioned by reaming and installing an oversized valve most of the time. You can fashion a vacuum test tool using a boost sleeve with a hole drilled in the end (hole size doesn't matter) as shown in Figure 2.

Remember: when in doubt, vacuum test!

Figure 2 – Make Tool from an Old Reverse Boost Sleeve

How to Make a Vacuum Test Tool from an Old Reverse Boost Sleeve:

1. Drill hole through end of sleeve.

2. Insert ¹/₄" rubber/plastic tube into sleeve far enough to block oil feed holes in the side.

3. Place a piece of rubber vacuum hose over the end of the ¹/₄" tubing to connect to vacuum test gauge.

4. Test for casting wear by inserting a good PR valve into bore and holding inboard with pick, while pulling vacuum through boost sleeve tool inserted into bore beyond EPC circuit.