Thread: Rebuilt Trans in February - 3rd to 4th Gear Problems w hardened installed

Hey Guys,

As I understand it, there is an ECM which is responsible for engine management, a TCM which is responsible for transmission management, and a PCM is basically the ECM and the TCM together. If I'm not mistaken, on our cars the PCM is literally one phycical unit that houses the TCM and the ECM. Is that correct?

Here's my problem (the VERY short version). My car is having major shifting problems where between 3rd and 4th gear the car starts jerking and bucking pretty hard. I had the tranny rebuilt back in February with a warranty so of course I took it back to the shop. The shop owner said the TC lock-up is occuring too early and as a result the engine bogs when lock-up occurs. The bog is then recognized and the lock-up is released. This cycles very quickly and causes the jerking/bucking sensation. He said he's extremely confident that a program reflash with the latest programming will fix the problem because it will make the computer delay the lock-up speed to where it should be.
Right now I have a DHP 1.0 tune and my question is: Can I have a dealership reflash JUST the TCM and leave my ECM tune alone?

Thanks for the help!

No, they won't flash just the trans, it will be both and it will be expensive.

4th gear is a common problem on these trans, bucking doesn't seem like a tc lock up issue but you may want to consult with the trans experts.

Crap, that's what I was afraid of. A reflash is about $100 (had to do it once before on a different vehicle).

Yeah, that's what went out in Feb. 4th gear clutch shaft finally pooped after about a year and a half of showing problem signs (I tried to milk it for all I could before it finally went). They showed me the clutch shaft and all the splines were worn completely smooth. They replaced it with a hardened clutch shaft.

So if a reflash has to be done, should I just go have it reflashed at the dealership and then have it reflashed with the DHP tune? I'm really unsure of how the programming works and if there is even a point to having the dealer flash it if I'm just going to put the DHP tune on it again. I don't know if anything the dealer does will remain if a DHP tune is done afterward, does that make sense? I'm kinda lost on what to do next. I suppose I could demod the car and wouldn't have to worry about it, but that would suck when I've had my mods for over a year now and they've not given me an ounce of trouble.

P.S. FoSho, your car is impressive. Props.

Your best bet is to find a local tuner that has powrtuner. If not someone with hptuners, have to buy credits with that though. If they flash a stock file onto the pcm and it doesn't resolve anything, let the trans shop know that. It may be their doing or a TC issue, I would post up a video in the trans section of what it's doing or send it to dave @ TEP to see if someone can offer more insight. If it actually is the shops doing, then they may want you to go to the dealer and have them flash it regardless, but i wouldn't do it unless they say they will pay for it if the problem is still there.

If that isn't working, I would find another compatible junkyard pcm and install that, if anything you can still keep the dhp 1.0 pcm or have a spare to send to reptile or someone to flash.

Yeah, that sounds like good advice. I actually kept my stock/original PCM when I swapped this one in so I'm going to swap it tonight and see what happens. If it fixes it then I feel better saying the 2nd PCM was the issue. If not, well, I think my trans shop would just say both PCM's need a reflash. Ha. I don't know if the trans shop will pay for a flash, but he did say that if I take the car to a dealer or whatever and they find a problem with the trans itself, he'll pay for it even if a new trans is required. So that's good.
He still seems convinced that it's a PCM or engine issue though. He had me do this test where I drove the car up to where it starts bucking (locking up too early) and then apply the brake with my left foot enough to turn the brake lights on, but not enough to really slow the car at all. His theory was that if the PCM was at fault, the pressing of the brake pedal would keep the TC from locking up and the car would drive normally. I did his test and he was right. I don't know if it GUARANTEES the PCM is at fault, but after what he explained to me, it seems more likely. In any case, I hope that it's either a PCM problem solved by a reflash (because that's not horribly expensive) or a problem with the trans itself (because that wouldn't cost me anything). If there's some crazy random engine problem that's causing this, I'll just drive the car off a cliff and get an ins. check.

I was thinking about having 3800perf flash my 2nd PCM but do you think going through Reptile is a better route?

Well, bad news. Swapped in the original PCM and it had no affect whatsoever. Yeah, the car felt a little different, but the same exact problem remains. Should I put the tuned PCM back in or does it matter. I'm really lost as to what to do at this point. It seems a transmission or related engine problem would make the most sense because it just seems an awful coincidence that BOTH my PCM's malfunctioned the exact same way resulting in the exact same problem.

So I decided tomorrow it's going to the stealership and we'll see what they say.

P.S. I guess this has become more of a transmission issue than a flash issue, so would a Mod mind moving this thread to the transmission forum if that is better?

Well, if you still have your stock pcm, there should be no point in going to the dealer unless you want to spend a bunch of money.

Post up a video of the problem. If anything, start looking for 3800 torque converters and flexplates if you find one from a N/A car, the bolt pattern is different for flexplates. The N/A TC will have a slightly higher stall as well.

(Thanks to the mod who moved this for me)


Well, an interesting turn of events this morning. I took a risk and dropped the car off at the dealership. They called me just a bit ago and said the TC is slipping due to either a mechanical defect in the TC, a bad solenoid, or bad circuit connector. Like I said the tranny shop said he'd pay for anything tranny related (because he was so certain the trans wasn't the problem). So this will be interesting and so far looks like it won't cost me a cent. I know the tranny shop is going to lose it on the dealership though. So I'm curious to see how that one turns out. I'll post back later...

Well THAT did not go well. The tranny shop dug his heals in the ground and wouldn't listen to anything until the PCM was reflashed. So I had the dealer reflash it and that didn't change a thing. Got in to it with the tranny shop and he told me he knows there is nothing wrong with the trans because he hooked it to a computer that takes complete control of the transmission and he said once he did that, the transmission acts totally fine. But once the car is given control, the trans acts up.
The dealership then changed their story and said that they will only pay for a mis-diagnosis IF they first guarantee their diagnosis is correct. Which all they have to do is NOT do that, and I assume total liability whether their "guess diagnosis" works or not.
Well they say they can't know what the problem is for sure unless I agree to a $400 tear the trans apart. Then they MIGHT be able to know for sure what the problem is. Right now they think there is some mechanical failure with or in relation to the TC. But because they "think" that's what it is, I have to pay them to swap that stuff out whether it fixes my issue or not. So the tranny shop says it's an engine/driveablility prob, not the trans, the dealership says it's the trans, and my usual mechanic says he's helpless because there are no codes/SES light and that the dealer has better diagnostic stuff than he does anyway. So as I see it, I can take a chance on the crooked dealership and pray they happen to fix the problem in the first shot or I can cut my losses and ditch the car. I really don't know what to do. I've never touched a transmission in my life so I don't want to try tearing into it myself and I don't want to just throw money at it blindly hoping that I get lucky and stubble onto the problem. This completely sucks. Paid $2500 to have the trans rebuilt and it only bought me seven months before either it or something else defeated the point.

What kind of spark plugs are in the car? How old and what brand are the wires?

Autolite 104's gapped at .055" put in like a month and a half ago, and Duralast 7mm wires installed last weekend. I know they're not the greatest wires, but I've run them for about two years with no issues (except when I found a hole in the insulation once, but a replacement fixed the issue).

I've been frantically searching for any solutions, and it amazes me how many people in so many different cars all describe the exact same issue I'm having. What surprises me even further is there has only been one confirmed true solution that someone did and that was just disconnecting the battery cable over night (which I tried with no success). Tons of people throw out ideas, but no one has posted back with confirmed successful results that I could find. I saw TPS's mentioned a lot so maybe I might check that as a last ditch effort?

Well we went to pick the car up yesterday at the dealership and I grilled the cust. service guy. I made him explain to me the details of exactly what they did and of course because he's just the liason for the customers, he didn't know a lot. He said that they have two main tranny guys in their shop and he said one has already looked at it. He said if I wanted he'd have the second one look at it this morning for an additional opinion and then would call me. Guy called me this morning and I actually got to speak to a tech this time. I asked him every question that I could think of and he either answered it or said he wouldn't know until he tore into the transmission.
One thing did occur to me last night however. As I was researching, I saw that the TPS was thown out as a possible cause, but no one ever confirmed this solved their problem. Well, I randomly remembered that my wife said she was coasting down a long gradual hill and she put the shifter into Neutral (she thought that'd save gas) as she coasted. Well the engine stalled sometime while she was in Neutral. I didn't really think anything of it because it never happened to me and wasn't anything I could duplicate or pinpoint to even try and fix. So I brushed it off thinking I wouldn't worry about it until it became an issue. I also remembered that sometime when I would coast down a hill or whatever, I noticed the RPM's would oscillate up and down, back and forth. Again, it was kind of random and only seemed to happen while coasting so I didn't freak out about it.
Well a while back my Jeep was having issues with oscillating RPM's and stalling. This was a little different because it would happen all the time at any speed. Never threw on a check engine light. Anyway, $30 TPS sensor ended up being the fix. So all this hit me and I told the dealership tech about it and he said in his 15 years, he'd never seen a bad TPS NOT throw a code, but he said for how cheap the sensors are, it couldn't hurt to throw a new one in and see what happens. Dealer wanted $165 to swap in a new TPS which just makes me roll on the ground laughing. So I'm going to pick the car up from the dealer today and swap the sensor myself and see what happens. With ALL the symptoms I have, I'm somewhat doubtful this will work, but I think it's worth checking.

I also decided that trying to make a decision on the trans when my trans shop says one thing and the dealer says something entirely different is only going to give me a stroke. So I decided after I try and fail the TPS test, I'll take it to two or three other local trans shops and have them do diagnostics on it. If they all or the majority say the trans is at fault, then I'll have the best one (best reviewed) go ahead and try to repair. IF the trans repair fixes the prob, then I might have to go after the shop who rebuilt it because it's still very much within warranty and he absolutely refuses to entertain the notion that something could be conceivable wrong with the transmission. So we'll see what happens.

Found these rather interesting:

http://www.automotivehelper.com/topic948504.htm

http://www.gmforum.com/archive/index.php?t-258858.html

Engine Controls - Intermittent Chuggle/No DTC's Set

Bulletin No.: 05-06-04-058

Date: September 07, 2005

TECHNICAL
Subject:
Intermittent Chuggle or Fishbite on Light Acceleration or at Highway Speeds with No Diagnostic Trouble Codes (DTCs) (Replace Throttle Position (TPS) Sensor)

Models:
1995-1999 Buick Riviera
1995-2004 Buick Regal
1995-2005 Buick LeSabre, Park Avenue
1997-2005 Buick Century
1995-2001 Chevrolet Lumina
1995-2002 Chevrolet Camaro
1995-2005 Chevrolet Monte Carlo
2000-2005 Chevrolet Impala
1995-1997 Oldsmobile Cutlass Supreme, Ninety Eight
1995-1999 Oldsmobile Eighty Eight
1998-2002 Oldsmobile Intrigue
1995-2002 Pontiac Firebird
1995-2003 Pontiac Grand Prix
1995-2005 Pontiac Bonneville

with 3800 V6 Engine (VIN K - RPO L36)

Condition

Some customers may comment on an intermittent chuggle or fishbite on light acceleration or at steady-state highway speeds (typically 80-105 km/h [50-65 mph]) with no PCM DTCs set. This condition may lead the technician to suspect the TCC circuit or torque converter.

Cause

This condition may be caused by intermittent operation of the Throttle Position (TPS) Sensor.

Correction

In observed cases, the Tech 2(R) is not fast enough to consistently detect this condition during a snapshot. It is recommended to use a DVOM set to the min/max recording mode. Connect the DVOM at the TPS connector (positive lead to TPS feedback signal pin and negative lead to TPS ground pin). Duplicate this condition by driving the vehicle. If the voltage dropout (less than 0.45 v) is recorded on the DVOM, replace the TPS sensor and re-evaluate the vehicle before continuing with other driveability or transmission diagnosis.

First, I want to wish you all the success with this dilemma on your transmission. Well, as you've seen from the technical bulletin that you posted about the TPS, this sensor can give a problem without a code being set. As far as that goes, any sensor could under the right conditions.

As mentioned in the bulletin, a DVOM with a min/max feature is required to catch the bad spot on the pot because of the speed that the dropout can occur. Using a DVOM without the min/max enabled is no guarantee either that you'll see the fault on the display since the update on the screen is slower. You could have the dropout occur, and the meter doesn't "see" it because of its update speed.

What happens is that the pot comes to an open spot and then the voltage will drop, or it comes to a larger resistance value and then the voltage will rise higher than it should for the pot's turns of the pot. I've even seen it where it becomes open, wait a fraction of a second and then it "heals" itself at the same spot. In any event, using the min/max of your DMOM will catch all of these different events. One other thought is that the cheaper DVOM's won't have a min/max feature. And if you do buy any DVOM, make sure it does have it.

A scope can also catch this for you if you have one. I sure do hope it's something as simple as a TPS. Good luck with your car!!!

Terry

Originally Posted by SliceTheRice

Found these rather interesting:

http://www.automotivehelper.com/topic948504.htm

http://www.gmforum.com/archive/index.php?t-258858.html

Engine Controls - Intermittent Chuggle/No DTC's Set

Bulletin No.: 05-06-04-058

Date: September 07, 2005

TECHNICAL
Subject:
Intermittent Chuggle or Fishbite on Light Acceleration or at Highway Speeds with No Diagnostic Trouble Codes (DTCs) (Replace Throttle Position (TPS) Sensor)

Models:
1995-1999 Buick Riviera
1995-2004 Buick Regal
1995-2005 Buick LeSabre, Park Avenue
1997-2005 Buick Century
1995-2001 Chevrolet Lumina
1995-2002 Chevrolet Camaro
1995-2005 Chevrolet Monte Carlo
2000-2005 Chevrolet Impala
1995-1997 Oldsmobile Cutlass Supreme, Ninety Eight
1995-1999 Oldsmobile Eighty Eight
1998-2002 Oldsmobile Intrigue
1995-2002 Pontiac Firebird
1995-2003 Pontiac Grand Prix
1995-2005 Pontiac Bonneville

with 3800 V6 Engine (VIN K - RPO L36)

Condition

Some customers may comment on an intermittent chuggle or fishbite on light acceleration or at steady-state highway speeds (typically 80-105 km/h [50-65 mph]) with no PCM DTCs set. This condition may lead the technician to suspect the TCC circuit or torque converter.

Cause

This condition may be caused by intermittent operation of the Throttle Position (TPS) Sensor.

Correction

In observed cases, the Tech 2(R) is not fast enough to consistently detect this condition during a snapshot. It is recommended to use a DVOM set to the min/max recording mode. Connect the DVOM at the TPS connector (positive lead to TPS feedback signal pin and negative lead to TPS ground pin). Duplicate this condition by driving the vehicle. If the voltage dropout (less than 0.45 v) is recorded on the DVOM, replace the TPS sensor and re-evaluate the vehicle before continuing with other driveability or transmission diagnosis.

Terry, I appreciate the input - thank you very much.


Well I swapped in the new TPS and I have good news and bad news. The good news that it seems the TC is not trying to lock up too early anymore and bogging down the engine. The bad news is that the fish-bite/chugging still occurs, it's just at a higher speed now. So at least SOMETHING has been done that's affecting it.
Before I swapped the TPS, it seemed like the TC was coming on WAY too early (like 25-30 MPH) bogging the engine and then letting go and locking up. This was by no means a fluid motion either. Very jerky and sporadic.
Well now it feels like the TC tries to lock but slips or it locks for a second and slips out. Its somewhat similar to before but not quite as violent I don't think.
Just for kicks, I disconnected the battery again and am going to see if resetting anything has any effect at all.

Yeah, disconnecting the battery again didn't do anything. I also called my orig tranny shop and he still maintains there is nothing wrong with the trans after I told him everything about the TPS and the change in symptoms. He even gave me two referals to other trans shops so I can get second/third opinions. He says what I'm describing sounds like a bad misfire. I still don't know one way or the other. Never in my life have I wished for a check engine light so that I had some kind of direction (aside from just cracking the trans open).
So I might try looking at the spark plugs just for kicks, and will probably take the car to some tranny shops and see what they say. Yesterday was kind of crazy so I didn't have time to get the car ready to take in to a shop this morning so it's just going to have to sit for today (which sucks because I saw gas prices went up and I'm still driving my 14 MPG Jeep 40 miles a day to and from work I [I know there are different schools of thought on who actually makes gas prices go up, but whoever they are, I hope they rot in hell - this is ridiculous]).
But anyway, if anyone has any more suggestions on what this might be, feel free to chime in.

Originally Posted by SliceTheRice

Yeah, disconnecting the battery again didn't do anything. I also called my orig tranny shop and he still maintains there is nothing wrong with the trans after I told him everything about the TPS and the change in symptoms. He even gave me two referals to other trans shops so I can get second/third opinions. He says what I'm describing sounds like a bad misfire. I still don't know one way or the other. Never in my life have I wished for a check engine light so that I had some kind of direction (aside from just cracking the trans open).
So I might try looking at the spark plugs just for kicks, and will probably take the car to some tranny shops and see what they say. Yesterday was kind of crazy so I didn't have time to get the car ready to take in to a shop this morning so it's just going to have to sit for today (which sucks because I saw gas prices went up and I'm still driving my 14 MPG Jeep 40 miles a day to and from work I [I know there are different schools of thought on who actually makes gas prices go up, but whoever they are, I hope they rot in hell - this is ridiculous]).
But anyway, if anyone has any more suggestions on what this might be, feel free to chime in.

Do you have a scanner where you could see the engine and transmission data? I doubt if you have a msifire as that would set the SES if you had enough misfires, but it wouldn't hurt to look at the misfire counters to see if there is any activity going on there. You could still have some misfires, but if there weren't enough in its sampling, the SES wouldn't come on. At least it wouldn't hurt to take a look. As far as the tranny data, you could confirm for yourself about the slippage of the torque converter. Did the dealership say anything about a code that was set by the tranny?

I don't have a scanner unfortunately and have never used one. I agree with you that a misfire would likely cause a DTC to come up (my usual mechanic said that as well). My misfire I had a while back was caused by a bad spark plug wire and it didn't throw a code either, but it was much less obvious/extreme than what I'm currently experiencing. The dealership said there were no tranny codes and the orig. tranny shop said that as well. The orig. tranny shop DID say, however, that he saw the check engine light come on and go off while he was test driving it up hills, but I've done plenty of hills (since the prob started) and haven't seen it come on once.

I dropped the car off at another tranny shop this morning (they say they provide free diagnosis) and we'll see what they say.

Bad misfires will cause the CEL to stay on. Moderate consecutive misfires may cause the CEL to blink.

That's good to know. Yeah, I would definitely categorize whatever is going on as "bad." haha.

Last night I was feeling really depressed about the car so to cheer myself up I went to test drive a Mazda Speed6 and a Legacy GT. The Speed6 was all torn apart when I got there though and they were replacing the turbo and a bunch of other stuff but I got to drive the Legacy. Not bad. I really don't want to have to get a new car though. If I can squeeze 2 more years (30-40K more miles) out of this car, that would give me time to be ready for the next car. Here's hoping.