Adam H
People's Republic of California
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Joined: 02/12/2007
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thomasinnv wrote:the governor is on the side of the tranny behind a small round cover. probably has a wire clip holding the cover on.
The cover mentioned above is at the right rear of the trans. When you remove, the governor will just slide out and make sure the weights are free and not sticking, You will see when you remove it. If it kicks down normally when floored and shifts at a higher rpm when floored disregard what I said prior about the electrical stuff. Also when the governor is out stick your finfer in the case where the governot spins and make sure the bore is smooth and not scored. If it is higher part throttle shifts you are after an adjustible modulator is what you need, also located on right side of case. To adjust, turn small screw 1/4 turn at a time and roadtest to your liking. Don't make it shift too late though.
Adam
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bill h
el segundo
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Joined: 08/02/2001
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Daveinet wrote:Is there an easy way to change the shift point for my TH475 transmission?
Shift points are usually changed by jiggering the governor springs and weights.
Quote: The modulator does seem to work - I had the vacuum hose come off and it stayed in first gear.
The usual symptom of a disconnected modulator vacuum hose is really hard shifting at all throttle positions. A failed governor drive gear or a stuck governor flyweitht or spindle valve will make it stay in first gear.
Quote: where is the governor?
On the right side of the main case, right where Adam said. Just forward of the tailshaft mounting surface, under a stamped cover held on by four bolts. The governor comes out easily, without removing the pan. Inspect the nylon drive gear and the springs. Check for freedom of movement. If the gear is worn, it could be pitting on the tailshaft or a tight bore in the case. I have had to ease a tight fitting governor in the bore with a brake cylinder hone.
Bill and Susan
84 Barth 30 tag powered by ht502/Thorley, Gear Vendors OD
Siamese Calvin and Airedale Hobbes
4WD Toyota toad
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zmotorsports
Utah
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Joined: 11/29/2007
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Daveinet wrote:zmotorsports wrote:... but the governor springs and modulator are where I would start without having to drop the pan... Mike. Ok, so the vac modulator location is obvious, but where is the governor location? It can be accessed without dropping the pan?
Dave as others have mentioned it is on the right side behind a round cover approx. 3" in diameter with square flange and four bolts holding it to the trans with a gasket under it and then the governor will slide out in a slight rotating manner. On light trucks I generally jack the right side of the vehicle up a few inches and that way I don't even spill a drop of ATF, but on a motorhome it isn't as easy so have a drip pan and a few paper towels handy.The springs are obvious around the perimeter weights to the center, however, one thing that is often overlooked is the valve itself. Remove the valve from inside the governor bore(make sure you pay attention to which direction it goes in) and clean everything thoroughly with brake cleaner and compressed air. Do not use the red shop rags around a transmission, I have torn them down after someone has cleaned parts with shop rags and found the filter plugged with red fibers. I always use lint free paper towels, even to set parts on while waiting assembly. After doing this make sure the valve slides without any obstruction inside the bore of the valve by tipping it one way then the other. Sometimes they will get a little burr and hang up in a certain spot. If it slide freely then reassemble and reinstall after putting the springs of choice on. If it does not slide freely remove and run your fingernail around each land on the valve until you find the burr and very carefully remove with either a fine file or emery paper. Sometimes even a knife edge will remove the burr also. Just remove the burr at an angle so you do not score or scratch the valve land itself. B&M as well as Art Carr and TCI all make governor recalibration kits that come with various spring and intructions that should walk you through the process probably better than I have described it. Good luck, Mike.
Mike & Chrystal (F315002)
2003 Monaco Dynasty/ 26' Haulmark Edge trailer
1996 Jeep Grand Cherokee toad
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KOG
Winterville GA
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Joined: 01/31/2001
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You can set full throttle shift speed about anywhere you want. This will also affect part throttle shift speeds. Using stiffer governor springs or lighter governor weights raises shift speed. If you raise full throttle shift from 4000 rpm to 5000 rpm (25%)for example, all of the part throttle shifts will also be raised by 25% unless you also then recalibrate the vacuum modulator. As Mike said, get a kit from one of the known good transmission builders and install parts as needed.
What you're dealing with is the fact that your 502 is tuned to run faster than a stock 454. Since it pulls beyond 4500rpm you may want to start by getting the full throttle shifts set to 4500. You do want to exercise some caution about this because you really don't want to overrev that thing. And big block Chevies really aren't fond of being run at high rpm for very long. Also bear in mind that turning the engine faster to use all of its power will get into the fuel. So you'll have to use a lighter foot when you're not trying to run full bore.
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Daveinet
il
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Joined: 10/29/2003
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KOG wrote:
What you're dealing with is the fact that your 502 is tuned to run faster than a stock 454. Just for clarification. This does shift much sooner than a stock 454 in another Revcon.
Quote:Since it pulls beyond 4500rpm you may want to start by getting the full throttle shifts set to 4500. You do want to exercise some caution about this because you really don't want to overrev that thing. And big block Chevies really aren't fond of being run at high rpm for very long. Also bear in mind that turning the engine faster to use all of its power will get into the fuel. So you'll have to use a lighter foot when you're not trying to run full bore. As far as over revving, does this also hold true for the 502? The context in which I ask is that the bottom end of this motor is considerably better than a stock 454. Its the same bottom end as the Ramjet. Is it still an issue?
Dave
FMCA F298817
'83 Revcon Prince 31' FWD
502 w/Thorley's & Magnaflows,
Howell/Edelbrock MPFI, Koni FSD,
Class A built for gear heads 
My Revcon Website
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Adam H
People's Republic of California
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Joined: 02/12/2007
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I had a blown CRATE 502 running 6500 rpm all day with no issues. Not that I am suggesting this, but is is a STOUT platform. Just get a governor recalibration kit from TCI or B&M like said by others, get the adjustible modulator and play until it is where you want. I would guess that you want at least a 5500 rpm full throttle shift to utilize the HP of your engine, that will be done with governor springs. If by chance you have to overhaul the trans, put the 4L80e planetaries and stuff in it for lower first and second.
Adam
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