so I did the dual feed clutch mod to my 4l80e
home rebuild w/new BW high energy frictions.
the hard parts looked good so I ran them.

I did not change the harness, nor the case o-ring--small leak, nothing I couldn't live with.


I have been troubleshooting a no-shift condition that I thought was in the tune (segment swap problem) but the PCM & trans segment work fine on another 4l80e vehicle.

I have been struggling to get any further, and would appreciate any insights.


I did stop by and ask a local transmission repair shop what they thought.

They told me it's likely the leaky connector has shorted the wiring, which has me scratching my head. I'm pretty sure atf does not conduct, especially since the internal harness is pretty much bathed in it.

 

Need more info titles says binding I assume like brakes are on in manual low ? Cannot push or anything? Or is this also in automatic 1st?
Also the No shift is it starting n low and not shifting or is it starting in second and just staying there.
Are any codes present,
Did you have the intermediate clutch apart as could have possibly reinstalled it backwards this will cause a bind up in manual low ?
Basically need a more detailed description to begin trouble shooting.

Trans fluid shorting electrical is very unlikely remember the whole harness and all plugs are submerge in ATF ,

 

yes binds like the brakes are on, feels like its in two gears at once. I have not tried to push it, but continuing to throttle up feels like it's binding harder. I do not think it occurs in auto 1st, but I'm not 100% sure I'm getting 1st gear.

The no shift was a result of my poor wiring, and I think is sorted. It would start in 2nd or 3rd ( I really cannot tell, the converter is really loose) and stay there.

After fixing my wiring, I was able to command 1st, 2nd and 3rd through HP Tuners. In auto , it would shift up though 1-2-3 (never got enough speed for 4th) and then go into limp mode.

Yes codes for both shift solenoids were present as well as slipping components.

I did have the intermediate clutch apart, and was unaware that I could put the sprag in backwards. That is totally possible. Can I test for that?


I have the truck not running to fix a fuel issue, and will get more data soon.

Thank you very much for your help!

 

Installing the intermediate sprag backwards will not cause a bind in low gear.

What mods did you make that are not stock?

 

I dual fed the direct clutches as per these instructions


http://67-72chevytrucks.com/vboard/s...d.php?t=668062

I also opened up the separator plate feed holes as per that same thread. I went to the larger sizes listed (3600 rpm stall converter)

In this unit I also blocked off the 3rd and 4th gear accumulators.

I have done the same mods to another unit, minus the 4th gear accumulator mod.

 

I'm in a holding pattern waiting for parts to arrive so I can get some more data.

I rechecked my trans connector for continuity to the pcm.

I am good everywhere except pin M which is the temperature 5v reference, it has no continuity on any pcm pin nor can I find which PCM pin # it is supposed to be at lt1swaps.com

I don't see how that would cause my issue though.


I did drop the pan, fluid smells and looks ok, minimal friction mat'l on magnet.

I will ohm the solenoids and replace the harness and try again.

Thanks for any and all help and ideas.

 

Are you sure you didn't so some mods to the 1-2 accumulator?

If you have an issue with that area the accumulator circuit will charge the intermediate circuit and cause a bind.

 

I didn't intentionally anyways. I will pull it out and check it against the atsg that I have it assembled correctly.

Thanks for the reply. I really do appreciate the help.

 

Yes the 1-2 accumulator and reverse servo are assembled correctly per page 73 fig 116 of the atsg.

I did find out why I never bothered to pin out the 5v temp ref---this unit does not have a temp sensor.

hmmm, could I have an older valve body in this unit? I thought a temp sensor was standard post '93

Are there other wiring differences that could cause a no-shift, a manual low bind or a limp mode?

I will have the fuel system back together and a new internal harness installed by this weekend.


Thanks for all the help!

 

ok back together with a new harness.

still starts in 3rd (or second, I cannot really tell)

now I cannot command gear changes.

no trans codes anymore.

still binds in manual low

 

Out of frustration I bought a '97 unit that I was able to test drive. Gonna put an HD2 kit in it and move on. Thanks for all the help and ideas. I appreicate it