[vhorn]

My son ice races an 1989 Caprice with a 305 and a th200-4r. He needs it to stay in first at high RPMs, but it feels like it upshifts despite the selector set to 1st. Does a th200-4r have a failsafe or limp mode that can be eliminated?

He dropped the pan off the transmission to change filter. The fluid was dark red, but not burned. Is there something he can change while the pan is off to prevent the issue? He wants to be able to use second gear, but manual shifting is fine.

 

[curtis73]

It's a failsafe for dummy drivers to prevent over-revs. If grandma puts it in first and gets on the highway, it will automatically shift to second.

I think it's a function of the governor? Been a while since I was inside a 200-4r. Lighter weights on the governor should do the trick.

 

[123pugsy]

It's a failsafe for dummy drivers to prevent over-revs. If grandma puts it in first and gets on the highway, it will automatically shift to second.

I think it's a function of the governor? Been a while since I was inside a 200-4r. Lighter weights on the governor should do the trick.

Firstly, about the dummy, well, OK, I are one..........

Secondly, the governor weights worked on my 700r4. Took it for a test drive and it wouldn't shift.

Does the 200-4R have a governor?

 

[Crosley]

The governor in the 200-4r is different design from the common GM design governor in the 700 transmission .

A larger secondary boost valve will hold 1st gear to a higher RPM.. That is an easy replacement with the pan off.

 

[vhorn]

Thanks guys!

 

[vhorn]

The governor in the 200-4r is different design from the common GM design governor in the 700 transmission .

A larger secondary boost valve will hold 1st gear to a higher RPM.. That is an easy replacement with the pan off.

Is this what I need?

Line Pressure Booster Kit - 700R4-LB1

Classic large-ratio boost valve gives you crisp, clean shifts without harshness. Fits GM 4L60 (700-R4), 200-4R. Part No. 700R4-LB1

www.sonnax.com

 

[vhorn]

It's a failsafe for dummy drivers to prevent over-revs. If grandma puts it in first and gets on the highway, it will automatically shift to second.

I think it's a function of the governor? Been a while since I was inside a 200-4r. Lighter weights on the governor should do the trick.

I cannot find a governor. Could I modify it myself? This car will never be used on the street, and if it will only shift manually that is fine. Maybe even weld the governor weights? (I don't know how the governor works in the transmission). The link below has images of a stock & modified 200-4r governor.

200-4r problems - The 1947 - Present Chevrolet & GMC Truck Message Board Network

200-4r problems Engine & Drivetrain

67-72chevytrucks.com

 

[curtis73]

The governor is behind the speedo drive gear

I have heard in some circles that you can grind/cut a little of the counterweight so it hangs on a little higher, but it's a total crap shoot. Seems like you keep cutting little bits with no change and then suddenly it shifts too high.

They also sell different counterweights with a little more accuracy.

From TransmissionCenter:

 

[Crosley]

Is this what I need?

Line Pressure Booster Kit - 700R4-LB1

Classic large-ratio boost valve gives you crisp, clean shifts without harshness. Fits GM 4L60 (700-R4), 200-4R. Part No. 700R4-LB1

www.sonnax.com

No.. That is the main boost valve. You need intermediate boost valve. TransGo 7-300 is one part number.

Or a full manual shift valve body may be a better option?

 

[ExcellenceAuto]

I just went through all of this before my 2004R blew up.
Grumpy Vette had the best advice I could find.

200r4 mod info

I found this posted else ware but figured some guys here could use the info also When you upgrade to a 200R4 OD transmission to get the benefits of the 0.67 overdrive, it is rare that the automatic shifting sequence occurs at the proper speed. Most likely you have lower rear end gears and a cam...

garage.grumpysperformance.com

 

[BogiesAnnex1]

Check this out

2004R Full Manual Release Valve Body

www.monstertransmission.com

Bogie

 

[curtis73]

(I don't know how the governor works in the transmission).

I'm no 200-4R guru, (nor am I actually a transmission guru, but I did stay at a Holiday Inn Express last night) but the basic operation of a governor is much like ignition advance weights in a distributor. The faster it spins, the further out the weights push (or pull) against a set of springs. Once it reaches a certain point, it triggers a shift. In the case of the 200, it uses a few mechanical means to determine shift points, primarily the throttle position from the throttle valve cable attached to the carb.

 

[vhorn]

Thanks for all your advice, fellas!
I will try the modification by Grumpy Vette (because it is cheap and I need it running this weekend).
I cannot help but wonder what would happen if I welded the counterweights together. Would that prevent a shift? Cause damage?

 

[Crosley]

I have cut and modified the 200-r4 governors ,, it can be a pain to do.. Not as easy to perform the mod since the pan needs to come down , fluid mess , yada yada.. Good luck ! Be Careful with the tiny thin springs on the weights.

 

[vhorn]

Modified the 200-r4 governor worked perfect! My son nearly won his first heat, had an 8 second lead on second place, then showed his lack of patience and experience by trying to pass a lapper in turn 4 and spun out with a lap to go. Ended up 4th.
Thanks again fellas!!!

 

[PHWOARchild]

I ran a TH400 behind a BBC in a Nova stock car. I wanted to initially run 2nd gear, but rear end gears I wanted were hard to find. I forget what they were, I wanted an overall ratio of 7 (trans gear x rear end gear).

So 1st gear it was for a few races. One night I was backing off for the 1st turn on the track, all of a sudden the car took a lurch forward and I was planted in the wall hard. I asked people if someone stuffed me into the wall... no. Then I learned that the car will up-shift to keep it from blowing. I took the governor out and safety wired the flyweights closed, end of problem.

 

[vhorn]

Thanks, PHWOARchild!
I was wondering if something like that was possible.