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1971 442 W30
Did the W30 take a diff Modulator Valve than the 442. Both TH400 but the w30 is diff inside.
Have a STANDARD TM15 on order which i believe is correct for 442.
Have yet been able to find any factory info.
Last edited by OLDsBARRY; Mar 7, 2026 at 07:05 AM.
Not sure if there was any difference in the modulator P/Ns.
We all know the W30 trans was factory tuned for firmer shifts.
Someone here has the catalog part numbers to compare 442 with 442 W30.
Whats your ultimate goal. Barking rubber on the up shifts or stock style shifts.
Whats wrong with the current mod and or trans. Is it a fresh rebuild?
IMO unless you are doing a museum style resto I'd install a TM50 adjustable.
That will allow further tuning W/O busting into the valve body.
New rebuild with a SLAM into R & D
Wondering what rate Mod they installed NO STRIPE
From what i have read the
442 ran at idle 13-15 vac
w30 10-12 vac because of its cam
im getting 9 to 9,1/2. Have no idea what cam i have. ITS NOT FACTORY
Soooo thinking the Mod Val might have been diff between 442 and w30
Think ive got the idle as low as i can
Put a line pressure gauge on it, see what the pressure is at idle. I mainly build performance transmissions for race cars or really fast street cars. The way I set them up, they definitely engage with a solid “thud”. It’s more of a quick engagement than a bang.
It’s possible the builder left the wave plates out of the forward and direct drum. There is also a center seal in the forward drum that’s normally left out for a heavy duty application.
According to the Jan 1972 Parts Book, there's no difference in the modulator P/Ns. Of course, this is for replacement parts purposes and may or may not reflect how the trans was actually built on the assembly line.
idle rpm @ 800 becouse of the cam. Everything elce is tunned in. Like u said it might be nature of the beast. Have read many times the W 0 (w30) trans was a hard shifter BUT have not found any Olds Lit stating that. We do know they did diff on the w30 trans vrs the 442.
idle rpm @ 800 becouse of the cam. Everything elce is tunned in. Like u said it might be nature of the beast. Have read many times the W 0 (w30) trans was a hard shifter BUT have not found any Olds Lit stating that. We do know they did diff on the w30 trans vrs the 442.
The OW (W-30) transmission had some different calibration, yes. It was no more harsh than any other transmission. They all came with "wavey" clutch plates which cushioned the gear changes. A higher idle speed will slam into a drive gear more than when idle speed is lower.
Nothing major will change until you get inside the transmission and make changes. Replacing the "wavey plates" and adding a clutch plate is part of it. There are many stages of change that can be done. This was documented in Oldsmobile literature that was part of the Blue Printing W Machines that appeared in the late 1960's. Matt69olds probably knows most of them.
While the Modulator is the same as Joe has shown, the Governor is different. While it may not help in today's world, there was another transmission that used the same Governor as a W-30 and that was a transmission with the ID tag of OL which should be found in the Delta 88 models with the Performance Engine. All other changes are internal.
The original vacuum modulators were a big black canister. After market are small gold ones and they don’t line up properly with the metal vacuum line. Standard Parts did offer the correct units but no longer.
any turbo 400 Governor can be modified to shift at higher RPM. I’ve done it many times.you need to snip off the two pins and take the weights and grind them for higher shifts.you put it back together using finishing nails that you flatten with a vise. I can post a detailed instruction page if anyone is interested.
