Hesitating/slow shifts... bad tune?

[big_news_1]

This is the 3rd transmission I've had trouble with in the last two years. They have all had drive/driven sprocket changes to change the final drive ratio, and they have all shifted sloppy/slow. I strongly suspect I have an incorrect tune for the transmission and it is causing hesitation and gear hunting at WOT. I also believe incorrect tuning is directly related to why my TCC shows 200-300rpm of slip when I use certain "speedo" settings in HPT.

I would be greatly appreciative if someone could look at a couple of my tunes and see where I'm going wrong. I used BanditGS's gear ratio change calculator to attempt to get this right, but the tranny still has the same symptoms.

BTW, the stock FDR for my transmission is 3.06. I had the drive/driven sprockets changed to make an overall FDR of 3.43. I also believe the tranny uses the 31-tooth reluctor gear. I can provide more details if need be.

[Bandit gs]

I replied to your PM, i'll look at your bins tonight (no HPT at work). Sounds like all the numbers are all off (TC slip shouldn't exceed 20ish when locked), I wrote up another way to adjust them in the PM.

One thing also, what is your calculated ratio in 3rd? Go for a drive and scan "calculated final ratio" command 3rd by just pulling down the shifter and see what the ratio is, should be 1.00:1 , if not your vss numbers are off. I'll try and look tonight and let ya know.

[big_news_1]

Sorry it took me so long to respond... thank you very much for taking the time to help me out.

I'll try to do some scanning this weekend. Tomorrow is no good because it's my wedding anniversary, but Sunday I should be able to give it some attention. Actually I might get to it tonight. I'll post info as soon as I have it.

[big_news_1]

Still haven't been able to capture any scan data, and I'll be gone for a little over a week. I'll make sure to post my findings sometime after the 28th. The car seems to have developed a bit of an electrical issue as of late, so I might have to address that problem before I can tackle the tune.

To be continued...

[bigbrian442]

I don't think your shift pressures should all be set to ZERO.

[big_news_1]

Shift pressures are set to zero because I have a 4T60E; i.e. it's vacuum modulated and shift pressures are controlled by the vacuum modulator. The '97 Bonnie w/L36 was the last Bonneville year/trim to get the 4T60E, unlike the L36 Grand Prixs of the same year. It's kinda good and bad at the same time, depending on how you look at it.

[big_news_1]

So I have a new finding...

In screwing with the WOT and part throttle shift speed/RPM settings and scanning the changes, I've noticed the 1-2 does not shift anywhere NEAR the settings. Almost identical problem to what BanditGS describes in his thread "WOT 2-3 won't shift....RussK"

I have the shift speed set to 35 and RPM set to 5400, but the when I go WOT the car simply accelerates through first, bangs against the rev limiter (6000 RPM), and doesn't shift until the rev limiter knocks the RPM down to 5600. It will shift at part throttle, but not at WOT.

What causes this? It's as if the PCM is ignoring the shift tables. There has to be a setting that I don't have configured properly.

BTW, my 2-3 shifts at WOT but shift speed/firmness is less than desirable. I can post the tune and/or scan if need be.

EDIT: Tune and scan files now attached. Please take a look and tell me what I'm missing.

[PDXGTP]

I didn't figure out anything by lookig at the log but I was thinking..

You don't have the perf shift button but who knows which one of those parameters the PCM is using. Your PCM is commanding to shift into second at 73 mph,
I was thinking just for fun, you can make all the paramteres the same in the part throttle, full throttle speed & rpm the same Normal perf & hot.

I'd copy all the the normal throttle stuff to the hot table, we are in AZ, its hot like being in the oven.

Does the PCM monitor Trans temp?

[big_news_1]

Good to hear from you, Thomas! Sorry to hear Bob's car had a setback


Anyways... I believe I have both Normal and Performance tables set identically. Is this not the case? I don't have HPT here at work so I can't check right now.

And yes, my tranny does give temperature info. When I was making those scans the tranny fluid was showing anywhere from 185-195 degrees Fahrenheit.


Is there any chance this issue could be related to some kind of torque management setting? Just throwing out ideas...

[PDXGTP]

I believe i still have a copy of your files on my laptop, if not you posted it but... i'll check.
I believe your perf & normal parms are the same but we can make your hot parms the same too, just for the sake of testing.
I have my laptop so I'll see how much I can get done while I'm in my 1:00PM meeting.
Later,

BTW, we going to see you Saturday night?

[big_news_1]

Thanks for taking the time to look at this stuff, man!

Saturday I won't be there . I need to get back together with you guys sometime and hang out. It has been too long once again...

[big_news_1]

Anyone have thoughts on this matter?

[big_news_1]

Who else has had problems with making changes in the tune and having the PCM "ignore" the changes? What was the solution?

Any chance there are hidden tables I can't see which need to be altered?

[mylittleblackbird]

Any ideas at all, guys... Absolutely anything... Short of swapping the trans into another 97.

[Russ K]

big_news_1,

Post your stock tune. Are the stock size (225/60/16) tires on the car? So for the gear change,
you swapped the 1.00 sprockets with a 1.121 sprocket set?

Russ Kemp

[big_news_1]

Thank you for popping your head in, Russ. It seems you're the go-to guy with problems like this!

I'm at work right now (night shift), but I'll post the stock tune ASAP when I get home.

[PDXGTP]

Russ.
These are his files that I had in my laptop.
The tune that says stock modified means its his stock PCM and we added his timing & tune so it would run right but we had been testing stuff in the trans.

it seemed like anything we tried had zero effect.
appearently we were trying different things on 3/30/08

Now what I can't remember is did we change anything back in 2006 when we swapped out his trans. In 2006 we swapped out his first dead trans and like I said, I can't remember if we made any changes at all.

The following year, 2007 we changed out his trans again because he had slipping problems and we installed the second trans that lasted even less time.

Some trans shop changed out the last one.

Ben lives on the other side of the 5th largest city in the USA so we don't see him too often.

it sure would be great to figure out his gears, slip, etc and be able to fix it with his tune.

Good luck.

[Russ K]

Guys, your making me beg for answers. Which tune is the actual stock tune from his car? And how was the gear ratio changed?
And are the stock 225/60/16 tires still on the car?

Russ Kemp

[mylittleblackbird]

Russ. Physically, the car should(unless he magically changed them and forgot to tell me) be stock sized 225/60-16 tires. The gear ratio sprocket changed from 1.000 to 1.121(since the trans swappings began).

The first tranny that went in had a 3.33 diff giving him a 3.73 FDR. The second tranny and current tranny both had the 3.06 diff or 3.43 FDR. That's what I know.... I think he used a spreadsheet from the forum here, and did the auto-scale in HPT for the transmission ratio change most recently.

When you ask for the stock tune, do you mean, the last known good configuration? If so, that'd be back to the original trans FDR (3.06), with only modifications to account for engine mods.

Thomas, to the best of my recollection, the second trans was just an install and tune later, but never got the gear ratio adjusted for? If I recall properly, he had the second trans in but was running on the tune for the first trans.

[big_news_1]

Russ... sorry for the confusion.

See mylittleblackbird's post pertaining to the sprocket change. It has the 1.121 sprocket and 3.06 diff for a FDR of 3.43. Still using stock tire size as well 225/60/16.

Attached is the stock tune for the car. Everything is factory except for 3rd gear TC lockup, which we raised to 255 to prevent it from locking (long story... thought the TCC was slipping when locked due to incorrect gear ratio tune). This tune also accounts for engine mods (cam, heads, injectors, etc.)

Let me also add that the car seems to have a ghost electrical issue where the climate control and CD player act funky. I have no idea if this has any bearing on the odd behavior of the transmission, but I thought I would mention it on the off chance the two are related.

Thank you for taking a look at this issue. It has been killing me for over a year!