Tranny won't command a 1-2 shift

[Eric Fischer]

This is a fresh rebuild after a hard parts failure.

The tranny won't shift out of first. It stays in first until I let up on the gas and then it overruns.

We took of the pan and the 1-2 accumulator was full (as should be) and a test indicated that it is applying the bands correctly. We inspected the valve body and all appears to be OK. The fluid is clean. We cannot determine why it will not shift. It appears as though the tranny is simply not commanding a shift.

The only other variable is the governor. I went to the GM 5000 RPM governor (GM part # 24202117 ). Unless this governor is bad from the factory, I cannot see how it would contribute to the problem.

Any ideas?

Thanks.

 

[jwaller]

their is only 1 band. and your problem is the governor. remove and inspect it and reuse the stock one if possible.

 

[Eric Fischer]

Well I put the stock governor back in.

The truck will shift now, but it's still not right. Part throttle shifts are delayed. For example, under mild acceleration it won't shift into 2nd until the RPM's are around 4000. And for example, it won't go into O/D until at least 65 MPH is reached.

Strangely, WOT shifts same exactly the same as before.

I expected that the new converter would affect the shift points some, but this seems excessive. There must be some other problem.

Any other ideas Mr. Waller? (thanks for your help ).

 

[Jimmy]

Kinda obvious,but is the TV cable properly adjusted,or possibly stretched out?

 

[jwaller]

tv cable adjustment. and possibly your trans is spitting junk out. and it keeps cloggin the governor. if you let this continue you will break the pistons in the input drum. believe me I've had this happen.

check the gov you removed. was it clogged/stuck?

 

[Eric Fischer]

tv cable adjustment. ?

The TV cable was adjusted per the instructions on this forum (push in the D-button, slide the cable sleeve toward passenger side, then rotate throttle to allow mechanism to self-adjust [I heard several clicks when I did this]). Perhaps this is normal, but I did notice that at the tranny end the TV "lever" does not contact the plunger until about 1/3 throttle....

check the gov you removed. was it clogged/stuck?

No, it looked fine. No clogs, no debris, the valve shuttled back and forth just fine. The fluid looks super clean. I don't think there was anything wrong with that governor. It's just a symptom of some other problem. I say this because the stock governor isn't behaving properly either (shifts are too late) and the raised shift points of the 5000 RPM governer are going to exaggerate the problem.

Since the governer's don't appear to be clogged and the TV cable is adjusted appropriatedly, I am not sure what to do next...

Thanks for your help.

 

[Big Dave]

http://www.syty.net/phpBB2/viewtopic.php?t=9578&highlight=tv+cable+adjustment

This procedure from Daron is saying to slide it toward the Drivers side and let go of button. Towards the Drivers side gives more pressure.

Have you fixed your problem yet?

Later,
Big Dave
Idaho Sy/Ty

 

[jwaller]

if the gov swap didnt fix the issue it's now in the vb. you need to pull the vb and go looking to see if you have any stuck valves in the vb. you could also have the vb valve in the vb stuck.

Q: when you have these shifts(albiet late), are they really hard or soft?
if they are hard I'd guess the tv valve in the vb is stuck.

 

[Eric Fischer]

Q: when you have these shifts(albiet late), are they really hard or soft? if they are hard I'd guess the tv valve in the vb is stuck.

The shifts were very hard. Late and hard shifts lead me to believe the TV valve was stuck as well. Recognizing that late and hard shift won't hurt the transmission (but are very annoying) I drove the truck around that way for a while and magically the TV valve unstuck itself! The truck had been sitting for a year (for upgrades) and maybe that caused the TV valve to stick??

Thanks for the help everyone!

 

[jwaller]

a stuck tv valve and other stuck valves can be very annoying to track down. a can of red lubeguard might be a very good idea for you to help with this.