Ls1Envy

iTrader: (6)

Got in the car yesterday and noticed it's shifting late at part throttle. Around 3500k or whenever it reaches 22mph. It should be shifting alot earlier, before it reaches the set mph shift. Then at WOT it won't shift out of 1st. Just bangs the rev limiter. The tranny has less than 1k miles on it, freshly rebuilt with the best parts. Thanks for any help.

Predator T/A

iTrader: (7)

with the stall it may be a tuning issue

performabuilt

iTrader: (25)

If i wont shift till a set MPH as you describe that does nt sound so much like a trans issue. I would scan it and look at the data stream to see whats being comanded first.

Ls1Envy

iTrader: (6)

I really hope it's a tuning issue. The thing is, it has been extensively tuned on the street and was driven without a problem for a few months. The problem just came out of nowhere. The only problem before was an occasional WOT 2-3 Shift flare.

performabuilt

iTrader: (25)

Well if its making the 1-2 shift just late at part throttle and allways at a set RPM theres nothing mechanical that could create that situation. I would look at sensors and tuning,codes etc first.

Ls1Envy

iTrader: (6)

The part throttle shift varies. It's between 3500-4000, depending on the pressure out on the peddle. But always at 22~mph

Ls1Envy

iTrader: (6)

So yeah i went out today and checked my fluid again. It looks fine......Took a spin around the street and when manually shifting from 1st to 2nd it's defiently slipping and when it does shift theres no more umpth! the converter absorbs almost all of it now.

****! Theres not even 500miles on this POS "rebulit" tranny. I'm so regreting moding this car now.

Gilbert@Ace Racing

Hate to see you regretting the mods! These f bodies can be a blast when in the right hands!

Based on the comments about the soft 1/2 shift I would say there is has been a leakage in the servo hydraulic circuits, input assy, pump etc... probably the servo as it is related only to the 1/2. Have your builder look at it before internal damage occurs.

It could be a tuning issue, but something changed physically or it would feel the same.

Ls1Envy

iTrader: (6)

The builder took down the Pan today and looked around. First off It looks like the band is smoked. There's a fair bit of sludge on the magnet and the fluid is quite dark for a >500 mile tranny. He tested the servo with air, it seemed ok. Shift solenoids, and all springs checked out ok. Another area of concern is a spot on the VB Gasket that is ate up....?

In any event It looks like the tranny is coming out. The thing I can't understand is how the band is burned already? Maybe all those engine braking shifts into 1st and slams into 2nd manually? The band was supposed to be the carbon fiber alto wide-band. No modyfiing was done with the drum. But At the time i remember reading something about doing something with the drum when you move to a wider band?

It's all very confusing to me Any comments on this would be appreciated. Hopefully I can figure this out and we can maybe figure out why I'm getting slip, and fix it without pulling the tranny. The band may still be usable. Heres pics of the pan and VB Gasket.

Ls1Envy

iTrader: (6)

I was mistaken the Alto Carbon band was not the Wideband.

performabuilt

iTrader: (25)

Well the VB gasket being torn could be the issue, The pictures not clear enough on my PC to make a good judgement but it could be causing a presure leak/crossleak

Gilbert@Ace Racing

I cannot make out the fluid condition... just curious more than anything here... what fluid did you use? I guess the wet stuff in the pan is cleaner right? I don't see anything red in those pictures... has your builder gone clean to the back of the unit? If not he needs to after this failure imeediately after a build... the goal is to clean all the debris from the pistons, shafts and other nooks and crannies that that stuff can hang out and bite you later... I see short cuts all the time. The inside of an automatic transmission is no place for short cuts!

The band servo could be the culprit. What setup did your builder use? A torn VB gasket could cause your symptoms. Also make sure that he checks the 1/2 shift valve, it could be binding, could be improperly installed if it has been modified with a shift kit etc...

The servo or accumulator is key here in my opinion.... which accumulator pistons are in your unit, plastic or aluminum?

Hope that helps.

g

Ls1Envy

iTrader: (6)

Heres a pic of the fluid.

I guess I was trying to avoid pulling the unit. But if it is like you said, better, because of what can happen later, I will.

As for the pistons aluminium ones replaced the plastics.

Any suggestions for brand/type for the new band?

performabuilt

iTrader: (25)

That fluid looks rough the borg warner / rabestos high energy or even the alto red lined would be good. But you need to check out the whole unit based on that fluid

Gilbert@Ace Racing

I am afraid you are going to find that the 3/4 clutches will be burnt in addition to the band. The reverse input drum needs to be inspected very closely to ensure it has not been damaged beyond its usefulness. From what you told us earlier you drove it hard... as well you should after a rebuild... The band will not leave the fluid that contaminated itself and the other clutches rarely fail. I am confident 3/4 is hurt based on that fluid condition.

I am afraid what you have suffered is what many guys do, a new transmission that has many high quality parts that are assembled by a good builder who does not understand what it takes to get one of these to a high horsepower / severe duty level. Not a negative shot at anyone here... just an observation. I have been there and done that! It took countless failures, we cooked a whole bunch of good stuff and many thousands of dollars before we were able to grasp what it took ourselves.

I wish you luck!

Ls1Envy

iTrader: (6)

Upon driving back home I realized what I originally thought was a slipping 1 into 2nd is really a no 2nd gear at all. I don't know if this changes anything.

The builder told me that I shouldn't sweat the fluid and when I asked about if the fluid could have damaged anything in the back of the unit, he said no, because the fluid dosen't flow from the band back to the clutches? I'm really debating on letting him even touch it again. The only thing is, money is really an issue and I think he was willing to do it for next to nothing.

Gilbert@Ace Racing

Well, the thing is he is wrong. The fluid is "pumped" throughout the unit for several purposes. It's not that the fluid would have damaged anything, the issue is excessive debris will be spread throughout the entire transmission... the valve body is my biggest concern. Not to mention, if the band was slipping the rubber seals on the piston inside the reverse / input drum are probably heat damaged. Need I go on......

Fluid is pumped throughout the transmission when the pump is spinning for oiling and lubrication, pressure supply for clutch application, cooler flow, converter operations etc.... bottom line is he does not want to go back through it. Which is a shame.

g

Ls1Envy

iTrader: (6)

Yes I researched it and made sure I had some of the best parts available. 5 pinion planents, carbon fiber band, clutches, sleeved drum etc. I was hoping i wouldnt have to go back into again.

now i'm just left with the decision to either go with the original builder or try to find another good builder, but one with more expirence with high performance applications. This guy is good don't get me wrong, he used to own a shop,5-6 years ago, but he did all stock rebuilds. Is there alot more than just getting the quality parts and putting them in? If so maybe i should look for someone else.

Gilbert@Ace Racing

[QUOTE=Ls1Envy]Is there alot more than just getting the quality parts and putting them in? QUOTE]

Only from the perspective of having my hat handed to me build after build, unit after unit, time and time again for over a year, in a 1998 Z28 that had an engine built with countless mod combinations by a SAM Graduate level LSx engine builder who is damned good at what he does... after learning a whole new level of humble can I honestly say... yes.

g

performabuilt

iTrader: (25)

I would agree you probably need to look for someon else as was mentioned theres more to it than just good parts and putting them in. While I wont say he didnt do something right there could have been many reason why your failure ocured. Likley a good builder could probably figure out what happened and why. And as I said before I couldnt see the tear in the gasket very well but that could even have been the entire issue a small crossleak can cause major problems.