lt170chevelle

iTrader: (2)

have a 98 blazer with a cammed 6.0 and 4l60e. The tranny recently lost overdrive and had an intermittent loss of all drive. I tore it apart and found a ton of black plastic looking debri scattered through out the tranny as welll as the usual clutch debri. The only culprit looked to be the stock converter failed so decided it was time to upgrade a few parts and put a stall in.
I did notice a little scarring in the pump housing. I rebuilt the pump, put some good steels clutches and band as well as billet forward and valve body servos.I cleaned the vb and cooler thoroughly.
I have not put a guage on it yet but has been feeling very sluggish and all shifts feel delayed and slow. i tried messing with the tranny tune but isnt helping much.
I did replace the vb plate with a new transgo one(since the original had a checkball stuck in it) and enlarged the specified feed hole per there instructions.
Im thinking the pump might not be up to snuff and isnt putting out enough pressure but hate to have to pull this tranny again.

Im looking for some advice on what to do. I have bandaided a similar issue in another transmission by turning the pcs torx screw a qtr of a turn to bump up pressure. Is this an option in this case?

Any helpful advice and points of interest would be appreciated.
Mako

performabuilt

iTrader: (25)

Well the first thing is to see if your getting presure rise with throttle or any at all so a guage would be the next step . Measure the presure with the harness unpluged you should get at least 170 PSI if so the pumps doing its thing ideally you want about 220 to 230 psi however so if you have at least the 170 i would consider using the torx screw to get to the 220 range. All this being good the next thing is to check for line rise as comanded which you can do with the tune in fact I would do that before i did the max line presure test. If you dont get any rise or little the PCS could be at fault and I would replace it. Even with a bad pump you should see some line rise when testing.

lt170chevelle

iTrader: (2)

ok will do. i will see about getting another guage today. I have adjusted the tune some more and is making a difference on the shifts now. Appparently i was not being aggressive enough with the tune. I will still check out the pressure though and go from there.

I am having another issue with moderate to half throttle cruising/slight acceleration in lockup when on the highway. Its a repeating pulsation feel.not gradual just a constant blip where it feels like the lockup or something is telling the verter to unlock or give for like a fraction of a second but just enough to feel. it happens like every second till i let off or give it more gas . i have the duty cycle set high to avoid pwm issues that are common from what ive read.
It just seems to be in 4th locked on the highway driving normal.

lt170chevelle

iTrader: (2)

Allthe shifts feel good now that i ave tweakedthe pressure shift tables in the tune. but am noticing a reoccuring neutral feeling when stopped and when i give it gas it revs up maybe 200 rpm and catches like its not in gear till i get right off of 0 tps . Also has an intermittent binding feel sometimes when taking off and feels like it binds then releases and lunges. I didnt see anything abnormal in the build besides the material from the converter and the scarred pump. Did i miss something?

Vince B

iTrader: (1)

What are you using for accumulator pistons?

lt170chevelle

iTrader: (2)

I used the billet pieces from sonnax(i believe) with all the pin holes plugged correctly with the supplied ***** and was careful when installing the pistons. Also they are definitely oriented correctly too. ( the early style has the piston facing the case vs the late facing the vb or vice versa..i forget without looking at the instructions or book.

lt170chevelle

iTrader: (2)

Also another problem is really showing its head now. on my way to work, as soon as 4th hits and verter locks, at any partial throttle under 50%tps , it verry pronouncedly pulsates like its either unlocking and locking back up or its losing pressure or something and then imediatly buliding back up. over half gas its unoticable, but driving normal is very irritating. Its like a slow revolution hitting every time it comes around(no relation to actual rpm though )

lt170chevelle

iTrader: (2)

Well an unfortunate update.I had raised the shift modifiers as well as the line pressure to get the trans shifting right.was feeling great. Then i had to drive it 5 hours out for a family emergency and driving locked in 44th at 70mph it would all the sudden unlock and shoot into 3rrd gear and not shift back or lock up. then after 10 20 mins of driving out of nowhere shift to 4th and lock up. this happened more and more frequently and when acting up and coming to a stop, when i went to take off it felt in neutral again and all the sudden grab and feel normal.
I also noticed when it loses 4th its just third and is like in neutral till i reach the rpm to move the truck..but if i shifted to 3rd it would hold and stay in gear and not just freewheel and rpms didnt fall to idle.
now i just got back home dealing with the same issues coming home and now it doesnt seem to be moving in reverse and feels like its hydraulically locking or binding when i have it running and in gear have to revvit up to get it too move like the parking brake is on.even in neutral the truck barely wants to budge only while running..
Im thinking some valve is sticking or something..i dont think its a stuck checkball since the new transgo seperator plate is only 2 weeks old .
What can cause these symptoms?

01ssreda4

iTrader: (96)

If you feel up to it you can PM me and shoot me your tune in an email and I can glance over the tranny section and see if anything sticks out.

lt170chevelle

iTrader: (2)

ok will do 01ssreda4

This morning i pulled out of the driveway just fine but right as i was about to go from reverse to drive it bucked and died..started it back up after cranking for a minute and put it in gear and it lugged and died. after starting again and put it back in gear and was rolling already i noticed the converter was locked in 1st gear. as i gained speed the coverter was locked in all gears no matter if i was pressing brake or in a low gear or stopped for that matter. After an awful time trying to get going from the gas station i got it on the highway and scanned it and it wasnt telling the vert to lockup. by the time i got to work it was acting perfect..no previous symptoms at all ..im confused and thinking about pulling the valve body again ..
Any advice?

lt170chevelle

iTrader: (2)

im thinking something in the tcc sytem is sticking or bad...this is a 200,000 mile transmission so maybe it has some wear that io overlooked?
I could really use advice on what could possibly be causing all these problems. I havent seen the trans temp get hot , but the aftermarket trans fluid and additive smells rank..Its the patc raptor blood green synthetic fluid and additive they reccomended. Im worried on just buying new parts and throwing them on to see if it fixes it and then dont.

Gilbert@Ace Racing

If that unit has 200k miles then your valve body bores are most likely worn considerably. I would recommend a new or reman piece. Now, it may not be an issue inside your valve body, there may be a cross leak in the hydraulic system elsewhere... but the high mileage vb is suspect at best.

But, if the fluid is dark and smells like a sunks *** then you have bigger issues. That can only come from an element that has been slipping. And after reading this thread I would suggest it's in your input assembly. If I had to guess, there is excessive clutch material in your TCC solenoid filter causing it to not exhaust properly, which will bring the converter clutch on.

Get the pan off of it and let us know what you see. If it has been driven any time at all with a poor line pressure rise, then there is going to be damage to the soft parts.

Also, regardless of the advice you were given there is absolutely no reason to use a synthetic fluid with additives in a well built transmission. None whatsoever! In fact yesterday I put a house brand fluid from my local parts store in an '04 GTO that I built a very high level 60E for. This unit will see well over 600 hp when the client turns his nitrous on. Do not waste your money on synthetic fluids inside your transmission!

Holler back when you get the pan off of it, in fact if you'd like to give me a call that would be fine. I might be able to point you in the right direction, ya never know right?

g

lt170chevelle

iTrader: (2)

Thanks allot for the response Gilbert. I already have a rebuilt valvebody on the way with all the updates in it. I will drop the pan tonight and see how the tcc solenoid looks. From searching the web ive read the high mileage vb and tcc selenoid are the two major problems like you mentioned.
Will post as soon as i get into it..i dont have high hopes at this point and am already looking forward to another rebuild in the near future.

lt170chevelle

iTrader: (2)

Just dropped the pan and man does that trans fluid stink..smells burnt and looks it.The pan wasnt slathered with material but just the the one spot hadsome decent deposits.I am alarmed at seeing some metal shavings/thin chunks of metal.I attached pics of the pan area where debri was as well as my finger wiped across it and picked up the metal shaving. Man how depressing. Imabout to drop thetcc solenoid and hope that its clogged. Im going to put a fresh filter on it and some new regular fluid. Hopefully it doesnt slip going from that high coeffecient of friction fluid raptor fluid to good ol dex/merc.Im wondering where this metal is coming from?!?

Gilbert@Ace Racing

Sure hate to see that in a fresh build. That is painful to see buddy.

Here's the deal. I know you're tired of working on it by now, but if you haven't realize it yet you'll find out that whatever caused that debris to be in the pan is not going away. It will not get better with a fluid change. Unfortunately the damage is done my friend.

Give us an update on how it's doing since you cleaned everything up and put it back together. Hopefully it's a happy camper, but I doubt it will be after seeing that debris in the pan.

g

lt170chevelle

iTrader: (2)

Well i the tcc filter was full of metal shavings and after i cleaned it out and it cured the constant converter lockup. Unfortunately 4th got weaker and weaker and now just wont hold no matter how much pressure i hit it with. 3rd is slipping anything over 1/2 throttle but 1 and 2 are still grabbing very well.
Could this be coming from the converter? It was a local converter shops. I know the pump had some scarring and I installed new vanes and rotor, maybe it somehow started chaffing up the scars? wasnt any high spots just low spots.
I did notice a strange grinding/groaning sound coming from the tranny under load and half to 3/4 gas shortly after rebuild.
My original thoughts was the converter clutch. What do you think could be the likely culprit?

01ssreda4

iTrader: (96)

I do not think this is a converter problem.

Gilbert@Ace Racing

Actually, if the TCC solenoid was full of debris, then the most likely cause of the failure is the TCC lock up clutch itself. The solenoid is located in the exhaust path of the circuit. Therefore if the clutch fails, the solenoid screen will clog and give similar symptoms that the OP described earlier. The fluid is filtered before it goes into the converter, so about the only way the converter solenoid screen can become laden with debris is if the converter eats itself up.

The failure of the 3/4 clutches is probably related to undue stress because of the other issue or they are simply just worn.

Either way, it's a mute point... the damage is done. That tranny needs to come out and be gone through again buddy. Sure hate to see that in a fresh build too.

Be sure to clean the cooler lines and cooler very, very well. If that wasn't done when the unit was repaired recently then that is the likely cause of this current failure... just thinking out loud on that one though.

Good luck with it!

g

lt170chevelle

iTrader: (2)

Thanks for the advice Gilbert. I thoroughly cleaned the lines and cooler before putting the tranny back in. I can only assume its the combination of the worn valve body and converter clutch. The clutch material in the converter is a .070 thick ABCO that is a Woven High Carbon material in a 9 1/2" converter built by a local shop. I would had thought it was more durable and could had withstanded some slipping regardless. I have literally gotten on this thing 2 times and only once through a 1-2 shift and the other just in 3rd, any other time i was driving her normal.

Gilbert@Ace Racing

Well once you get into it let us know what the converter and internals look like.

g