No downshift to 1st. after stopping

["Black Ice"]

No downshifting to 1st. gear after stopping. If I pull the shifter back to 1st. gear while stopped the put it back into O/Drive it will start off in 1st. like it's suppose to. What could this be? Thanks

 

["Black Ice"]

New transmission rebuild, less than 100 miles.

 

[TexasT]

Have you put a gauge on it? Usually has too high pressure when it won't go back to low when you stop. Over 100psi ?
What boost valve did you install?

 

["Black Ice"]

Can someone point me on the correct pressure to buy so I can check mine out. I will get back with yall on the reading I get. Thanks

 

[turbo6randy]

You will need a gauge that reads 0-300. It screws in to 1/8" pipe thread. I like about a 6' hose also to read it under hood or while sitting in car.

 

["Black Ice"]

Ok thanks Randy. I have a video of the detent cable plunger sticking at the end on the way out. It won't let me upload the video.

 

["Black Ice"]

Could a bad pressure switch be the cause, main has 2. IDK if new ones was put in when it was rebuilt.

 

[turbo6randy]

As TexasT replied, it's most likely too much pressure. The detent could be the cause. If the pressure spring and or boost valves were changed that could be the problem. No the switches are not the problem. A pressure gauge is a very good investment. I like to know pressures on any fresh rebuild.

 

[plcguru]

Without knowing pressures its just guessing like others said above. Could also be a couple clicks too much on the tv cable but u really need to check pressures...
For a gauge I have the gearwrench/kd 3343d. Amazon has it for $39. https://www.amazon.com/GEARWRENCH-3343D-Engine-Automatic-Pressure/dp/B000CO7VJC

Harbor freight has a $45 400psi gauge which isn't best for resolution but if ur in a rush there's probably a store near you... Engine and Transmission Oil Pressure Test Kit

 

["Black Ice"]

Without knowing pressures its just guessing like others said above. Could also be a couple clicks too much on the tv cable but u really need to check pressures... For a gauge I have the gearwrench/kd 3343d. Amazon has it for $39. https://www.amazon.com/GEARWRENCH-3343D-Engine-Automatic-Pressure/dp/B000CO7VJC Harbor freight has a $45 400psi gauge which isn't best for resolution but if ur in a rush there's probably a store near you... Engine and Transmission Oil Pressure Test Kit

Without knowing pressures its just guessing like others said above. Could also be a couple clicks too much on the tv cable but u really need to check pressures... For a gauge I have the gearwrench/kd 3343d. Amazon has it for $39. https://www.amazon.com/GEARWRENCH-3343D-Engine-Automatic-Pressure/dp/B000CO7VJC Harbor freight has a $45 400psi gauge which isn't best for resolution but if ur in a rush there's probably a store near you... Engine and Transmission Oil Pressure Test Kit

Without knowing pressures its just guessing like others said above. Could also be a couple clicks too much on the tv cable but u really need to check pressures... For a gauge I have the gearwrench/kd 3343d. Amazon has it for $39. https://www.amazon.com/GEARWRENCH-3343D-Engine-Automatic-Pressure/dp/B000CO7VJC Harbor freight has a $45 400psi gauge which isn't best for resolution but if ur in a rush there's probably a store near you... Engine and Transmission Oil Pressure Test Kit

 

["Black Ice"]

Thanks yall, I just ordered a pressure gauge kit, the one u pictured. How do I check it? Do I get the pressure in each all gears with foot on the brake to get the right pressure? This is gonna be a new adventure for me. Guys for helping me guys.

 

[plcguru]

Thanks yall, I just ordered a pressure gauge kit, the one u pictured. How do I check it? Do I get the pressure in each all gears with foot on the brake to get the right pressure? This is gonna be a new adventure for me. Guys for helping me guys.

Procedure is below from the atsg manual... but yes basically as you wrote. 1000rpms on the tach, foot on brake, test in each gear at min tv and then again at max tv.
The pressure port to use is on drivers side of trans above the shift linkage

 

["Black Ice"]

How do I get "Max TV" pressure? Do I unhook the t.v. cable and pull with my hand. So I won't have to foot brake the car with pedal to the floors? I know I sound crazy but this is all new to me. Thanks Guys yall have been a real big help.

 

[TexasT]

Glad you are moving into a gauge and pressures.

Yes on the unhook the tv cable from the throttle arm.
I did my pressures with the car on stands and some more while driving.
Nice to have a helper in the car to do the throttle and move the shifter while you are under the hood giving the tv cable a pull and seeing the gauge. A third to record the data is nice too. Pressure should jump with authority when the cable is pulled. If it doesn't or is lazy you could have a sticky valve in the vb. You might try modulating the tv cable with the rpms up to possibly clear an obstruction. Pressure should also return to base pressure when the cable is released.

 

[Anthony P]

Procedure is below from the atsg manual... but yes basically as you wrote. 1000rpms on the tach, foot on brake, test in each gear at min tv and then again at max tv.
The pressure port to use is on drivers side of trans above the shift linkage

since the BRF valve body wasn't specifically called out in that ATSG page, I retrieved the page from the GM service manual.

for those who have missed past sharings... the entire GM service Manual for 86-87 is available electronically via the link below. suggest saving each section for easy reference in the future. never know when web pages will disappear.

Electronically Linked and Searchable Manual

 

[TIMINATOR]

Sticky or bad governor?
TIMINATOR