kyoytey1693

iTrader: (7)

Hey guys I have a 96 Trans Am with an LT1 and a recently rebuilt 4L60E (like less than 10,000 easy miles on it) and recently I have been getting an 1870 code followed by the 1670 that gives me the hard shifts.

The tranny has a shift kit and a factory speed stall converter and the tranny guy seems pretty good so I trust that the issue isn't actually the tranny. I think it's in the tune. I say that because since it's been rebuilt I've had a Hypertech tune in it with no issues. Recently unistalled the Hypertech but in the middle of deprogramming it the unit went bad on my. I wont even get into the bs I've heard from HT but since that happended I have had the 1870 issue.

I have a local guy that has helped me retune the car but we cant get the TCC to lock up. The computer is commanding it but it's still not happening. I found this thread where the guy was having the same issues and he zero'd out TCC minimum press and zero'd out TCC Solenoid minimum PWM.

I gave this info to my tuner but he is using Tunercat and does not have the ability to change these settings. He admits that he isn't the best with trans tuning but seems to have done great so far and is still trying to help me get this figured out.

Can any of you tell me what I should try or tell him to look for? I really need some help on this one. Living with no TCC lock up is one thing but the hard shifts are killing me. Any advice would be greatly appreciated and sorry for the long post.

kyoytey1693

iTrader: (7)

No one? Come on, I know that post was way too long but I really need some help. I know you guys are smart enough to tell me what is going on with this thing....

2xLS1

iTrader: (25)

I've never known the tune to cause P1870. If the pcm commands lockup and it doesn't it's almost always the transmission.

kyoytey1693

iTrader: (7)

I know and in most cases I would agree but knowing how well the tranny has just been gone through, I'm wanting to say it's not the culprit. Did you check out this thread?

Specifically, his last post...

FINALLY figured it out!!!! It was all in the freakin tune.I tried every possible combo in the TCC pressure tables and got it.With EFILive I had to zero out TCC minimum press.And zero out TCC Solenoid minimum PWM and now its like I have a 5th gear!!!! Locks up nice. I'm glad I took the trans apart though anyway.I put a higher stall TC in,The beast sun shell and some other stuff.

I've PM'd to ask him directly but he hasn't replied. Or do you still think it's the tranny?

DRIVER456

The reason your getting the hard shifts its going into the "trans DTC fault max pressure enablers" In my tune I shut all those off so you don't get the hard shifts.Without EFILive or HP Tuners I don't think you can adjust what I did.What do you mean by"factory speed stall converter"?If its a higher stall then stock you will get the 1870 code.I'm trying to remember what codes have to be shut off. ..............Paul

kyoytey1693

iTrader: (7)

[QUOTE=DRIVER456;15194012]The reason your getting the hard shifts its going into the "trans DTC fault max pressure enablers" In my tune I shut all those off so you don't get the hard shifts.Without EFILive or HP Tuners I don't think you can adjust what I did.What do you mean by"factory speed stall converter"?If its a higher stall then stock you will get the 1870 code.I'm trying to remember what codes have to be shut off. ..............Paul[/QUOTE

I was trying to say the torque converter is new but is the same specs as factory. It's not a higher stall. Sorry for the miscommunication.

We did shut off the 1870 code but the converter still wont lock up and then it goes to giving me the hard shift issue.

kyoytey1693

iTrader: (7)

Ok, so just to eliminate any possibilities of the Hypertech failure being the cause of my 1870 issue my tuner bought a stock tune for my car and we installed it today. The car seems to idle a little better. When driving I sometimes get a hard 1-2 shift and other times it feels normal for the shift kit.

The kicker is the fact that the TC never locks up and now it doesnt show any codes at all. No 1870 code, nothing. I've driven the car at least 30 miles or so since we installed the new tune. Before it would set in less than 10 miles or so.

My tuner is lost. I'm completely lost. What the hell is going on with my car? If you guys have anything else to offer I sure would appreciate it cause I have no clue where to go from this point.

pdsq98gt

Is the o-ring on the input shaft of the trans cut or missing? Sounds like there is a pressure loss somewhere in the trans if maxing out the tcc pressure got it to work.

kyoytey1693

iTrader: (7)

I dont know about that. Honestly trans internals are a little beyond me. I can change fluid and filter but thats about it. Otherwise I'm dangerous.

We weren't actually able to max out the tcc pressure though. Since mine is a 96 it doesn't have those capabilities. At least that is what my tuner told me. Or maybe that was a limitation of his knowledge of Tunercat. Is there a way to max tcc pressure with Tunercat on a 96?

2xLS1

iTrader: (25)

The thread you refer to as someone else fixing the same problem says they zeroed out the minimum duty cycle table. That makes absolutey no sense from a tuning stand point. Common practice is to raise minimum PWM values to around 90% or even higher. TC has the table to adjust the maximum DC on a 96-97 F-body. Stock settings is 90.2 I don't see any minimum tables. There are coolant temp and trans temp thresholds to enable TCC. What are you using to show that the computer is commanding lockup since TC doesn't have a scanner? Again, it the computer commands lockup and the TCC doesn't it is usually the transmission or the signal not getting to the trans.

kyoytey1693

iTrader: (7)

He is using Autotap to monitor everything. At one point we tried cutting back the duty cycle on the TC just to see what it would do but that didnt change my lock up issue. He says it is commanding lock up but its not actually happening.

DiabloFormula

iTrader: (58)

What kind of shift kit was installed?? Did your trans guy install a new updated TCC reg in the pump? Which one did he use? EPC will also cause the 1870 code. If the Computer is commanding lock up and the trans is not locking up, it's in the trans. I'm betting that TCC clip in the pump wasn't installed correctly and popped out.

kyoytey1693

iTrader: (7)

I believe it was a transgo kit. Not sure about the TCC reg in the pump. I have an oppointment scheduled for Friday so, hopefully I will know more after that.

Thanks for all the input. I will update the thread when I get something out of him.