I am wondering, is there a way to tell the Trans to NOT go into Overdrive unless you are above 40MPH. My 90 RIV will not go into overdrive untill 48MPH and I like it.

My 87 Formula though likes to go into OD even at 25 or 30 MPH if I am not gassing it and just cruising around. It boggs the engine way down.

I have the TransGo "Mr Shift" Gil Younger NoYoYo SysKoKal Shift kit, and a 3.73 rear axel ratio if that helps.

John

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87 Formula Yellow/Black

5.1 TPI Automatic
Baer 12" brakes 4 wheels, KYB AGX Adjustable Shocks & struts, Custom Leather interior, WAAAY TOO MANY MODS TO LIST

87 Formula TPI (5 Speed) Yellow/Gray STOCK

1967 Buick Riviera 430hp Turns high 14's (Not bad for 4300 lbs)

83 Camaro (Parts)
83 T/A (parts)

http://www.3rdgenformula.com

 

Try adjusting the TV cable. Other than that, I would run it in "D" until you reach a speed around 50mph, and then manually shift into "OD". That's what I've done with every GM 700R-4 or 4L60E vehicle I've owned, even for those with the column shifter. It is the best for the drivetrain, IMO, as they all seem to lug and vibrate in OD at low speeds. Hope this helps.

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1990 IROC 350
Mods: Too busy trying to make it run right to mod it.
Airfoil, Dynomax cat-back, MSD coil, 180 t-stat, Bald Eagle tires,
Hypertech fan switch, Accel 23# injectors, Holley module, ported plenum,
Ported Daytona Yellow stock base, Moroso valve covers, other stuff,
Streetdampr, Ruger P95DC, hot wife, new oil filter, !cats, !TBC, !AIR.
18.0 @ 85MPH since I'm one big-a$$ MF
"It's better to have and not need than to need and not have."

 

Except for the TCC lockup, the trans makes all its decisions based on info received from the output shaft and TV cable. With 3.73 gears (had 2.73's originally, correct?), it is thinking the car is going a lot faster than it is. So, it shifts.

You need to adjust the govenor. I know that, but can't tell you how to do it. I believe transfixleo addressed that not too long ago, or perhaps he or Dana of Probuilt can respond with details.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4. 2.93 limited slip. 2-1/2" cat-back, ZZ3 intake, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LG4 CC system w/'87 LB9 block, ZZ3 cam, ported World 305 heads, Hooker 2055 headers, 3" Catco cat & 3" catback, restalled TC, Spohn SFCs).
57 Bel Air, my 1st car. '66 396, 9.7 CR forged TRWs, Weiand Action+, Holley 750VS w/4150 conversion, GK 270 cam, Magnum rockers, Jacobs Omnipack, 1-3/4" Hedders & 3" Warlocks, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, MegaShifter, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Idles smooth @ 600 RPM in D. Best 15.02/95.06 @ 5800' Bandimere (corrected 13.93/102.4 @ sea level).

 

You need to install lighter springs in the governor for higher light throttle shift points. Going from 2.73 to 3.73 I would assume your wot shift points are lower too, if so lighten the inner governor weights.

 

To adjust the TV Cable skip the book method and do this: Press the D button on the adjuster and loosen the cable setting. Now, have someone floor the gas pedal while you check to see if the throttle plate is open all the way. Usually they are off a little and will wiggle. Do whatever you have to do to get it open solid. Now, with the pedal still floored, press the D button and pull the cable casing (the black tube) back as hard as you can and release the button. You now have the engine, tranny and gas pedal all in sync at WOT. Mark the cable so if for some reason it gets moved you can know where to put it again. The problem with the 'self adjust method' is that it bends things and puts them permanently out of whack. It is also the full TV setting, which is theoretically what the GM method does.

The 3.73 gears are what are making this happen as I doubt that the engine is 'lugging' even at those speeds. The TV Cable adjustment may help that. If it is still too low for your tastes/power curve then as Jay and five7kid said it is goig to be neccessary to go with lighter governor springs. If you did the SK install you should have a variety of governor springs to choose from. Try changing just one to a lighter spring and see what happens. If you do not have them then you will need a B&M governor calibration kit which will make it real easy too. Just remember that you do not want all of the shifts to be on the late side. In fact you are better off if they are a little on the early side. You never want the engine to 'hang' at an RPM as that means you are losing acceleration and wasting power.