00 ss w/texas speed 408 yank ss4000. put together with trans(60e) built for nos. car would not shift properly and eats alternators. sometimes charges sometimes doesnt. latest alternator is from dealer,w/same symptoms.pulled trans after 200mi and sent back to builder.
He claims trans was right when it left his shop the first time but re-built for free to save face. after re-install with fresh converter and flushed trans cooler it "chatters" on moderate acceleration in low gear and slips on moderate acceleration in upper gears.
Any one find electrical probs causing this? Ran w/tech 2 hooked up and data looks ok. no codes,shows trans shifting properly. only have 7mi. on new trans and converter. Afraid to ruin another trans.

 

Yes certainly solve the electrical issue as low voltage can cause solenoids not to turn completely on and all sorts of sensor issues.
However I would suggest you also have the line presure checked make sure its adequate it sounds like low line and typically if anything low voltage would cause low PCS current and higher than normal line presure.
You will either need to purchase a guage or take to a shop to have this checked.
If you have a shop close by that can check it to elimiate any electrical issue causing the low line I would unhook the harness from the trans and drive it there in manual 2nd gear , It will be in limp mode and will set lots of codes that will need to be cleared but will set the line to max to prevent slipping if the issue is not in the trans.If it is in the trans will make no difference one way or the other.
Try and keep the RPM under 3000 when driving along like this.
If the presure is good and normal after check proceed with correcting electrical grimilins and see what happens , If low then you will need to contact your builder again.

 

Thanks for the info, it truely is appreciated. If I unhook the trans harness and manualy select a gear could I test for symptoms?
Am i reading your responce correctly that low voltage would increase line pressure, therefore not allowing this problem?
At the original tune for this engine the tuner left the line pressure at max and set very early gear changes to help limp it home as we knew there were trans issues.

 

You should return the tune to stock for now, And yes on manually You will maunally be able to select both 2nd and 3rd with the harness unhooked but not first or 4th .

Very early gear changes can also cause issues fyi

 

Please forgive me for being so **** about details but very nervous about ruining another trans. If I unhook the trans harness and say put the car in 2nd. if it is an elec problem it should hit the converter and pull normally? What I mean is will it bypass all tuning etc? Any chance of causing damage by making one hole shot like this?
Again thanks for your time and expertise.

 

What should line pressure be? Checked in park with harness unhooked?

 

depends but somehwere between 80 and 120 psi pluged in at idle. With harness unplugged between 170 and 225 PSI it varies according to what all he did when he built it.

I would not try a whole shot with harness unplugged while it is unlikley to cause any issue with the trans if its ok , You will be launching in second so its unlikley you will get the desired result.

 

unhooked the trans harness today and tried a 2nd gear launch. seemed ok. no traction with rain but hopefull that it's in the tune