JP8528V6

hey guyz...got a question about the above subject...modulator valve in the transmission...is this where the throttle cable goes into...cause i was told today that there is also a vacuum switch that goes into it...if there is one i'd like to know...thanks alot guyz...

1991tealRSt-topGuy

your 700R4 doesn't have a vacuum modulator

i belive what your tranny does have is called a throttle valve

JP8528V6

yea...i just found my service manual and found that out...thanx for the help though man...i read there are modulator valves that work in the valve body though...once again...thanx for the response...i just gotta figure out why i'm having problems shifting...i'm gonna pull out the valve body this week and check it out...i think something is sticking in there...but i'm not an expert...we'll see what i come up with...

TomP

A bummer with the valve body is that it's a good basket for catching metal filings that fall down from the clutches & band. All the valves should move easily and snap back closed when you move them with your fingers. If one seems like it's getting hung up in the bore, you'll have to remove it, and try to either check for metal filings, or you might have to polish either the plunger or valves or the bore in which the valve rides in. Try to remove any metal filings you create.

Also, make sure to wash the valve body down with a spray brake cleaner before reinstalling it (WITH NEW VALVE BODY GASKETS, a set is about $5 from GM but I think it needs to be special ordered!) to the transmisison.

Also, while you're in there, cut open your old filter. I use angled cutters and screwdriver to separate the metal bottom of the filter assembly from the upper plastic section. Then, unfold the filter medium. If you see a ton of metal inside that filter, start saving coin up for a rebuild.

Plus, you (and I) have one of the "bad" years of transmissions. Common failure of the 85-86 trannies (happened to my first trans) is that the fluid pump "aerates" the fluid, causing foam, which puts air into the trans- and the fluid pump starves for fluid. This causes the pump to run dry, and the metal pump gear eats into the aluminum case, metal shavings go everywhere, and next thing you know, you're being raped by Lee Myles for $1300 for a rebuilt trans that only lasts a year and a few months... the jerks.

Gumby

Yep, why I kinda get down and don't really like the 700R4, that pump crap is common and then the tranny is done for. Not many places will even try, and some will go ahead and let your rebuild it but knowing it gonna take a crap. its just scrap metal after pump failure. They say there is no way to clean it out right. They could but new is cheaper. or good/used/rebuilt.

too bad there is not an adapter plate fo the turbo350, sure there is or one could be easily made. you can get a nice built turbo 350 out of a cataloge for under 1000 and it has a good name behind it.

700R4's are great when they work, but when problems come up, your wallet gets thin fast.

1991tealRSt-topGuy

yeah, it sucks that you guys dont have any other trans option really for an automatic

a TH350 wouldnt be too good (dont get me wrong- its durability is excellent), because it has a 2.62 first gear where as a 700R4 has a much lower first, so your off the line is gonna suck
and theres no overdrive, so even if you run a really low rear gear, your highway RPM's are gonna suck

all in all its not really a good choice

something like a 2004R would be better