I'm currently swapping a '99 L67 Series II motor in for a blown L36 Series II motor in a 1996 Park Avenue. I'm also putting in a 4T60-E(HD) from a supercharged car in place of the regular 4T60-E. I was wondering whether the transmission line pressure regulator (correct name? It'* the large clynder on the top of the trans that has a vacuum line on it) uses vacuum before or after the supercharger?

I know the MAP, fuel pressure regulator, and boost bypass valve use vacuum after the supercharger, and the brake booster and Evap controls use vacuum before the supercharger, but I can't seem to figure out what the transmission line pressure regulator uses.

It seems reasonable that the regulator would use vacuum after the blower for higher line pressure under boost, but there aren't any vacuum ports large enough on the blower or LIM that would feed the regulator. If anyone as any advice, I'm all ears. I'd also appreciate a vacuum diagram from a 96 SII */C car (b/c they have the 4T60-E and not the 4T65-E trans).

Another question: Does anyone know if the regulators are the same between the regular 4T60-E and the heavy duty 4T60-E. The one on my HD trans was damaged, so I changed it out for the one on the regular transmission. I checked the numbers on both and they were the same, so I assume that means they're identical???????

I am unsure...but thinking about it.

After the SC doesn't make sense, because you'd need a check valve to keep from pushing pressue instead of vacuum when rpms were up and boost was kicking in.

I'd think before.

That'* how I have it routed right now.

Maybe someone with a 4T60-E supercharged car can confirm this for me?????

If someone else doesn't do it soon, I will for you when I (finally) get home tonight.

I've got the car running now (amazingly on the naturally asperated computer, but that'* getting fixed as it'* running WAY too rich right now) and I've gotten a chance to feel the transmission shift. I've got the vacuum line hooked up before the supercharger like the brake booster, and it seems to shift very nice and firm (for stock and a 62K bone yard trans).

I'll probably leave it like this unless anyone else has any insight? I don't want such a simple thing to lead to premature trans failure.