Must accelerate engine to engage reverse on c4 transmission.

[rcantu01 0]

Hi again, all,

 

The 250/c4 combination is in my 69 coupe, which PO had sitting for 10 years. All forward gears seem to engage fine, but putting it in reverse generates a lot of smoke from the tailpipe and shuddering until it bucks into gear.

 

Short of checking ATF (was almost empty, now filled), are there are other things I can check, or is this typically an automatic (pun intended :)) must-rebuild situation? Also - what would cause the smoke?

 

Thanks,

[JC69Stang 0]

Not sure about the smoke, but I would double check the fluid level now that you have circulated the fluid in the trans. The converter will use alot of it up.

 

there is a vacum modulator on the back of the trans, make sure the hose or steel line connected to it is ok, you can also replace the whole modulator really easy to do.

 

Band adjustment maybe?

 

Otherwise I would say you may need a rebuild.

[bnickel 10,004]

i would change the vacuum modulator on the trans to start. the smoke could be that the diaphram in the modulator is ruptured. it probably smokes when in the forward gears when you get on it as well, but you may not be able to see it.