Dave Carney

Starting a new thread on my tranny troubles which have resurfaced, yet again. Here is the original thread and the history on the problems:

https://ls1tech.com/forums/automatic-transmission/744499-converter-unlocking-locking-unlocking.html

(Briefly stated the car had a converter lock, unlock, lock situation and occasional missing first gear. The trans (FLP IV with 48k miles) was rebuilt by my local trans shop and during the rebuild they discovered a broken spring in the pressure regulator/accumulator and another in the valve body....got it back, and in forty miles lost first and fourth due to a dead shift solenoid.

Got the car back again from the tranny shop Friday, and once again after 40-50 miles first gear was gone and the car was starting out in second, it worked ok this morning on the way to work but on the way home, did not have first at all. Last time one of the new shift solenoids had died but now, I am thinking something else caused that.

On a hunch, I let the car sit for a couple hours, then backed out of the drive, put it in OD, and first was there!, did it again, first was there again. At work, I pull forward out of my parking stall, never engaging reverse. This is an important clue because it's happened that way both times. What would the use of reverse have to do with whether or not I will have first for the trip?

Also, at a stop light on the way home, I decided to select first and see what happened. I was met with a substantial groaning noise and a vibration/slip sensation. I still have fourth this time, unlike last time, and no code has been thrown (yet)

Car goes back to the shop for the third time tomorrow.

performabuilt2

sounds like to me that you are having a valve body issue

Gilbert@Ace Racing

Wow, talk about a guy having problems! Man I hate to hear it.

Try to find out specifically which valve in the valve body had the failed spring and which spring was installed.

There may be a cross leak when in Manual Low. And that may be the reason for the noise and strange slip sensation.

The difference between Manual Low and O/D low gear is... in Manual Low the Low / Reverse clutch and the overrun clutch are brought on. The issue may be in the overrun clutch or input drum assy. Meaning when the overrun clutch is brought on the forward clutches may be losing pressure. There could easily be an issue in the 1/2 accumulator at the valve body. These are a handful of hydraulic possibilities.

The forward sprag may be slipping as well, it is released in Reverse and brought on in all forward ranges except 4th. This is an example of a mechanical possibility, if the sprag is worn out it could easily be the culprit. (This is where I would focus my attention until I ruled it out.) Ordinarilly there are other symptoms associated with the failure of this part... but I have seen stranger things.

Unfortunately there can be many reasons for an intermittant no 1st gear.

Gonna be hard to pin this one down without having the car here to work with.

Good Luck Dave.

g

Dave Carney

Thanks guys, I'm very appreciative of the help! Just dropped the car off, used the reverse trick this morning and had first for the trip there. Last night while I had first working (by engaging reverse prior to engaging first) I slipped it into manual low and there were no noises. So the noise seems to be tied to loss of first and manual selection of low.

I think when this loss of first happens I lack line pressure, some kind of leak like you said. Last evening when I went from park to od to begin my trip home you could not feel the engagement at all, which is not normal, but that may just be because it was going from park to second instead of first.

Dave Carney

Ken called, he tried 2 different valve bodies, still no joy. He's got some kind of box where he can take the pcm out of the loop and command shifts via this box, anyway, he says when he did this the trans works fine. He believes I have an electrical problem, harness or pcm (???). I don't know. Anyway it's going to another shop now for diagosis/repair. This has my stomach in a knot and i'm not sure whether to cut my losses now or let this other shop take a stab at the electrical. It's on the way there now, Ken said he was confident this can be fixed and this guy is the guy that can do it. After everything, I have virtually no confidence and yet, because me and my family have a pretty lengthy and good track record with Ken and his work, I trust him. So that's where its at. Gil, Performabilt, anybody think I heading down the wrong road?

performabuilt2

if he took the pcm out of the loop then it should be an electricla problem do you know if he tested it at the tranny plug or jumped in right after the pcm if the wires coming from the pcm are burnt then it could be the harness maybe they got on the exhaust....if he tested it at the plug then i dunno man......maybe the transmission driver in the pcm went out hard to say.

performabuilt2

Well if he used a shift box and could not duplicate the problem that would tend to point at the wiring or PCM thats not to say theres been no damage done. Many peopl fail to realize and electronics issue can fubar a trans. I have seen them killed off by every thing from a MAF sensor to a TPS and other things. Trans generally gets the blame and many times when you see someone pop up with a repeated failure even in some cases from multiple builders which I have seen post like that here. This very well may be the case. We actually have one of those shifter boxes we send to our customers if this type problem arises and its proven invaluable and saved both us and the customer many $ chasing our tails.

Dave Carney

Thanks. The way he explained it to me the only wiring between his control box and the trans was the trans connector and its wiring. But I don't know for sure. I'm thinking something was damaged during the R&R of the trans.

performabuilt

iTrader: (25)

Well sounds like he did use a shifter box and he would be correct that would completely eliminate the transmission mechanically as the cause. However it would not nessesarily eliminate shift solenoids such as the 3-2 etc. Since these boxes rarly have the ability to do any real test there.
But the first thing really to do in a situation like this is get a scanner on it drive it try to duplicate the problem and watch the data stream.

coolformula

iTrader: (21)

I had that issue once on a older car it was teh shift solnoid. 1st would always almost work from a cold start but not after that.

Gilbert@Ace Racing

Any updates Dave?

g

Dave Carney

Thanks for asking. Ken ran it over to the shop he recommended for electrical diagnosis, Thursday of last week. The guy there is too busy to look at it. He's had it a week now and done nothing whatsoever. His helper quit and he's just backed up. He's a heck of a nice guy on the phone but I have lost hope now, as of this evening that he will get to it any time soon. I've posted the car for sale or trade on various websites. I'm bummed.

Tomorrow I have the day off and I think I will liberate the car from the shop its at now and bring it home in preparation for trading it. Today I called Chance transmission here in town, to see what they get on a tranny just in case it is the tranny and I can't get Ken to see that. Chance has a long history here in wichita, a good rep, and more diagnostic capabilities I think then Ken has. They were quite helpful and offered to run a diagnostic on the Firebird if I wanted. I'm thinking about taking it there.

My backup vehicle is a '79 Dodge van. Today I fealt what I think is the tranny slipping on it. Swell, Murphy strikes again. I have a 35 mile round trip to work every day, I have had the Bird only 2 days in the last month and it's really straining things. I wish you were closer Gilbert, the car would be at your place already. As it is now, I wouldn't take it out of the city limits.

Gilbert@Ace Racing

It's hard to find good help these days! I am lucky to have the guys I have... and I know it.

Hate to see you sell it before you get to enjoy it this year. Take it to Chance and see what he has to say. If need be give me a call and I'll offer an opinion based on what he finds.


Thanks for the nice words Dave!

g

Dave Carney

was bringing it home from the electrical shop (the guy did finally get to it and said that it's fine, electrically and that he thinks something is going on in the valve body, particularly when hot, he checked voltages at pin connectors, drove it, put a scanner on it, found nothing electrically wrong) and I set a P0758 2-3 shift solenoid code x3, then it went into limp mode, for the first 10 miles though it drove fine, same darn thing. I'm running it over to Chance here in a bit.

Dave Carney

Well it was a big day. (Big day, not good day lol) Explained the history to the guy at Chance, they are not anxious to come in after somebody else has worked on it but they were quite willing to do a diagnostic, etc and go from there. He thought it sounded electrical in nature, but that was his guess based only on my description. Now that I've driven it a few times and studied the service manual, I think this trans is just going into limp mode when it gets to a certain temperature and point in the trip, about 10 to 12 minutes into a trip and the trans temp has to be higher than 155 or so. Before it gets to this point, it's fine. As part of limp the pcm would command third gear only and no converter lock. When you turn the key off and let it sit a couple hours, then drive it, it's fine at first, for about 10-12 minutes and trans gets to operating temp, then it limps out.

So anyway, sitting there in the lobby waiting on the Mrs to come get me and Ken calls me on the cell. I had not called him or even told him I got the car back from the electrical diagnosis guy. The guy had called him (or maybe ken called to check, I don't know) to let him know he found nothing electrical and he thought valve body. So Ken was calling to offer to build be another tranny at no cost, but... he told me he would be using a core he has laying around, and would re-use a lot of the new stuff (clutches and bands and stuff I'm sure) that went into the current trans (I'm sure alot of it is perfectly good but it makes me uneasy about possibly introducing the fault to the new one), and it would be built striclty stock. He still has no idea what is causing my troubles though and he's not sure the new one will do anything to solve the problem but in his opinion it would eliminate the tranny completely. Part of me thinks "but wait, what if it comes back even worse than it is now?" since that's what basically happened the last time.

I told him I was sitting in the lobby at Chance and why I was there. He offered to pay up to $100 if I wanted to get their diagnostic/opinion. They would not be able to get to it until after the weekend. After further discussion w/Ken decided it best if nobody else messed with it at this time. So, I took the car back home and had a long discussion with the Mrs, who has exercised incredible patience over the last month this has been going on. What should we do? As of this evening, I have several cash offers to purchase it as is. So, we decided that we gave it a good faith effort but its time to move on. Sale of the car is pending to a nice guy, and multi-Formula owner.

Dave Carney

*******UPDATE**********

I think I have the car fixed and I did not sell it. I waited until I got a couple hundred trouble free miles before posting. That has happened now, and while it may all go to hell tomorrow, it appears to be fixed (big knock on wood).

First a refresher since this has been going on for so LONG ...

1) Converter locked, unlocked, locked, unlocked, once or so per trip. First gear sometimes felt like neutral. Cause> low line pressure caused by broken springs in the trans. Had trans rebuilt and stock converter put back in.

2) Got car back from rebuild, felt like line pressure was too high (but I was used to the 3500 stall and lower str), drove ok for about 30 miles, then lost first (and maybe second). MIL set, defective 1-2 solenoid (which was new). Replaced. Still felt like high line pressure (violent jerk when selecting gear). Also idle was too high (1000 rpm)

3) As part of troubleshooting the idle/line pressure my trans guy, Ken, asked me to turn the idle down. I did that with edit, idle was still too high though, well above commanded, looked for and found vacuum leak in pcv line. Idle came down, line pressure came down (due to increased vacuum)

4) Car drove ok for 30 more miles, than, felt like I lost first, very difficult to pull away from stop. No MIL though. Could get all gears back when car was key cycled and trans was cool, then would lose them when it reached operating temp. Took car back to Ken, he tried 2 different valve bodies and no joy. Also tried stock type modulator, no luck. Ken said the tans shifted ok with the Schaefer shifter he used to take the PCM out of the loop. Suggested it was probably electrical and I took it to a electrical shop he recommended.

5) Car sat for a week there, then finally got looked at, nothing unusual found electrically. Electrical guy thought there was trouble in the valve body. Asked me about my custom tune, told him yes custom tune but nothing related to trans and tune worked fine for 50k + miles and old tranny. Picked up car, had P0758 code times 3.

6) Ken offered to build another tranny, in the mean time I had an offer to purchase the car as is for cash. Now we get to Saturday.....

Saturday I finally had the car here at my house for the first full day in a month. Decided to study the trans tables to see what if anything was changed in the initial tune, years ago by the guy who helped me with the base tune. Found 3 things changed, Desired shift time, and 2 torque management tables (torque management was deleted). Decided to take these 3 tables back to stock just on the one in a million chance that this is what was driving my problems. Got Edit out, used my tune before the last one as my base (this would have the old idle speed) and copied over the stock version of these three tables. Did the burn, drove the car, no problems! Drove it more, still no problems. So, I must be a genious..right ? Wrong! But you knew that already ....in fact, I would discover later, I had not even properly saved those trans tables before exiting, so I hadn't changed anything at all but the idle (and factor x). Here is to the best of my knowledge what really happened, we'll flash back in time a bit:

Got out the Helms service manual Friday night and studied the P0758 code. This code is for an electrical problem on the 2-3 solenoid. It was set when the electrical guy was testing there for voltage. The manual said that if this code was set the PCM would do the following (limp), command max line pressure, command third gear only, unlock torque converter and freeze adaptive shift. Wait a minute, that's just what I have I think when this crap happens, third gear only! So, at this point I talked myself into myself into this: The PCM is commanding limp and that is the cause of my latest problem.

With this determination made I set about to see what was causing the limp,. Could be a lot of different things. So, I decided to study the trans tables in the edit file that was in play when I had the troubles. Guess what? Edit could not open that file. I kept getting an error. That was odd I, never had that trouble before. But while odd, it did not strike me as serious initially, that took a few hours to soak in... then I thought, maybe I had a bad burn that day I tried to turn down the idle, now, things and ideas really started to flow....my old laptops monitor had died recently and I was forced to use my new laptop without a serial port. No problem, picked a $36 usb to serial cord at best buy and did a read with Edit, then did the burn.

Later, I tried to use that same usb to serial cord with Autotap, it would not recognize it at all, no matter what I did. So, I ordered a PCMCIA serial card to use with Autotap, that did not work either. So I ordered from Amazon a Keyspan cord that I found recommended here at LS1tech. That worked with Autotap. Because it worked with both edit and AT, and because it arrived just in time for Saturday, I used that one when I did the burn back to last tune and put the Best Buy cable away for good.

I think then, that all my problems after the dead 1-2 solenoid were caused by a problem in the pcm burn when I attempted to reduce the idle to stock. I think the burn was good enough to keep the car running and going but something was not right, a bit, a byte, gigo, I don't know, but once the trans got into temperature range for diagnostics, the pcm threw it into limp mode.

When I reburned it back using the Keyspan cord and the tune file before the problem one, all was well. One thing I remember is that the read with the Best Buy cord took 20 minutes (faster than the old laptop), the read with the Keyspan took 40 minutes.

I had a lot of luck (even when I thought I was having none at all). The electrical guy threw the code that caused me to go to the Helms manual. Desperation for keeping the car, kept me chasing the problem even after I had a deal in place to sell the car. I happened just by chance to grab the Edit file before the messed up file, generally I'd use the last file as my base from which to make my change. The Keyspan cord came in in time to use it Saturday. The Best Buy cord failed with Autotap. Take away any of those things and this car is gone.

I also had the most information of anyone involved so it was my problem to solve. I had Ken's thought's, the electrical guys, I chatted with a guy at Chance transmission who told me I was losing more than first gear if it was that hard to pull away from a stop, and I was the only one that knew about the laptop/cord situation. (even though Edit gave no indication that anything went wrong during the read or the burn) I knew the history of the car, what fealt right, what fealt wrong, what seemed possible, what seemed unlikely.

Damn, I've talked too much. I did want to put this out there though in case it helps someone else some day.

I want to thank all the folks who popped in to help me, and particularly Gilbert who I PM'd a lot when I knew I was on to something over the weekend. Preciate the feedback Gilbert!

Gilbert@Ace Racing

Holy cow! That's one heckuva read Dave!

But, I figured you were onto something when we were talking this past weekend. And as I have stated countless times in the past to co-workers, the guys next door, enthusiasuts here and of course you... I have zero doubt in my mind that an erroneous tune can not only wreak havoc on shifting commands but will also roast a 4L60E transmission. You have dodged a bullet my friend... and how cool is that!

Good to see you at the end of the road with that ordeal!

Thanks for getting back to us, that info is priceless. Stay in touch.

g