Transmission Slipping 3-4th gears

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kwalsh
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Transmission Slipping 3-4th gears

Post by kwalsh »

Howdy,

Got a transmission that is slipping on my '03 CC, 136k miles. I recently changed the transmission filter & fluid (5qts of fluid) in an attempt that the issue would go away. It hasn't.

Here's the description: When the 4L60E shifts from 3-4 it will engage, disengage, re-engage. I assume this is the TCC going in and out? This usually occurs around 45-50 mph under light to moderate throttle & is more pronounced when going uphill. I have to punch the throttle to force a shift into 3rd. The transmission used to downshift on its own; now it doesn't.

When I feel the 4th gear struggling to maintain speed the tach fluctuates about 200-400 rpms. By the seat of the pants I can feel the hesitation/surging. The truck wants to shift but doesn't, unless I punch the gas peddle. It is as if the 4th gear doesn't have the strength it used to. Hope this all makes sense.

Any ideas on what is going on would be very much appreciated. Hopefully the fix is easy & affordable.

Thank you.

Regards,
Kevin
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HenryJ
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Re: Transmission Slipping 3-4th gears

Post by HenryJ »

Sounds like the converter is not locking properly? Or is it really the overdrive? Could be a solenoid? Could be the converter, could be the OD / reverse clutches?
Either way you are probably looking for a rebuild at that mileage. That would be your best investment.

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Re: Transmission Slipping 3-4th gears

Post by kwalsh »

Ouch. That's what I was araid of. I think I will need a yeasty beverage (or 2) after work today.
Thank you for the reply HenryJ.
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Re: Transmission Slipping 3-4th gears

Post by HenryJ »

I am not looking forward to it myself. I have been doing all that I can to lengthen the life. Or I hope I have been. My fluid gets flushed and exchanged every 30k miles. At least I try to.
I have added mods to firm things up.
I am still under 92k miles, but I know that I will be needing a rebuild in the next few years too.

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Re: Transmission Slipping 3-4th gears

Post by kwalsh »

I priced out a soft parts rebuild kit, $200 - $300 and quotes from the local transmission shops are, $1000 - $1500 for the rebuild.
:cry:

Yesterday I noticed that my head gasket is leaking. :rant:

My dilema: Do I fix the CC or trade it in for a full size bowtie? :?:
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Re: Transmission Slipping 3-4th gears

Post by killian96ss »

kwalsh wrote:My dilema: Do I fix the CC or trade it in for a full size bowtie? :?:
Most members who have asked this ? went full size because of the extra space, increased power, and same or better gas mileage. Your finances and planned usage for the vehicle should make the decision for you.

Steve
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Re: Transmission Slipping 3-4th gears

Post by kwalsh »

The wife gave me the green light to start shopping for a full size.
She mentioned that we will need the extra room for the little ones anyway.

I hate to see my CC go; I was hoping to get 200k before I let her loose.
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Re: Transmission Slipping 3-4th gears

Post by killian96ss »

It's too bad the rear seat space is so small in the cc's. If it wasnt for that problem I would be looking for another one.
Since my kids are only getting bigger, my next vehicle will most likely be a Trailblazer SS because its not real big like the full size chevy's, it has plenty of power (400 HP stock, well over 500 with a GM supercharger), all wheel drive for lots of traction and safety, and better gas mileage than a cc.

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Re: Transmission Slipping 3-4th gears

Post by kwalsh »

So I decided to wait awhile before I made this post.

About 1 month ago I removed the HPPIII programming for the firmer shifts. Since then I don't have the slippage on the transmission like I once did.
Weird. :blink: :?:

The most noticeable slippage was going uphill around 45mph in OD. I would have to force the shift into 3rd with a punch on the gas peddle. Now I don't have to force the shift to take place and the tachometer doesn't float like it did before.

Since the issue has gone away does this mean my transmission is about to have catastrophic failure (the calming before the storm)
Or was it the HPPIII?
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Re: Transmission Slipping 3-4th gears

Post by HenryJ »

Was it a converter lock issue rather than "slipping" clutches? Did you program 4th to shift -12 to eliminate the "searching". Could that be what you are describing?

Maybe you have a converter that is going?

Maybe the increased pressure was highlighting a valve body problem?

Dunno :shrug:

:popcorn:

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Re: Transmission Slipping 3-4th gears

Post by kwalsh »

The shift points that I adjusted were very minor -3 or -4 I believe. I never adjusted the shift points in an attempt to remove the searching. My assumption is the higher line pressure in the transmission was the culprit.

I'm puzzled.
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Re: Transmission Slipping 3-4th gears

Post by HenryJ »

Me too. If it was the converter failing to lock, that might show a code. Any codes pending?

Paul and I both had success running more than -10 on the 3-4 shift to eliminate that "searching" "slipping" feeling on that shift.

Can you see the converter lock up now? It is that little rpm drop after the 3-4 shift. Maybe it is not locking at all now?

With the kind of mileage on your tranny, I'd start saving for a rebuild. I still think your days are numbered. At least that is how I would feel about mine. Start shopping for a good re-builder and add a few heavy duty parts if you plan to keep the truck. Otherwise, sell it now while it feels "good". ;)

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Re: Transmission Slipping 3-4th gears

Post by kwalsh »

No codes. I haven't had a DTC code in awhile. never had a code related to transmission or converter.

HenryJ, you just jogged my memory. Months before the 'searching' took place between 3-4th I noticed that the rpms would not drop once the transmission shifted into 4th like they once did. The CC went from a noticeable (visual & noise level) rpm drop to maybe a 200 rpm drop. I thought nothing of it, other than, "maybe I need to do a transmission flush". Of course I didn't flush the transmission until the searching started.

Yes, it is time to either do a transmission rebuild or get rid of the CC. Unfortunately I don't have the $ right now for a newer truck, but the wife did give me the permission slip to get a full size. I hope the CC "feels good" until I can save up enough $.
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Re: Transmission Slipping 3-4th gears

Post by HenryJ »

Did you ever do the transmission filter/flush?

I have heard of a few that had the converters going. Never did I, personally, have a case where someone had to walk home because of it. Well at least not the late model 4L60E transmissions.

"Speed doesn't kill, suddenly becoming stationary does." - Richard Hammond
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Re: Transmission Slipping 3-4th gears

Post by kwalsh »

I've dropped the transmission pan, refilled with fresh fluid & replaced the filter each time.

Flush 1: 50k
Flush 2: 100k
Flush 3: 136k
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Re: Transmission Slipping 3-4th gears

Post by HenryJ »

So did you actually change 100% of the fluid , or just the 5 quarts with the pan drop for the filter change?

The "Redneck flush" or a fluid exchanger is needed to do all the fluid.

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Re: Transmission Slipping 3-4th gears

Post by kwalsh »

I stand corrected on my posting above of "flush".
Did not perform a true flush; I did not do a 100% fluid exchange.

I only did a 5qt addition of fresh fluid with pan drop & filter exchange.
Last edited by kwalsh on Thu Sep 30, 2010 5:07 pm, edited 1 time in total.
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Re: Transmission Slipping 3-4th gears

Post by HenryJ »

If you plan to hold on to it for a while, you might consider doing the redneck flush.

"Speed doesn't kill, suddenly becoming stationary does." - Richard Hammond
"Speed is just a matter of Money - How fast do YOU want to go?"-Mechanic from Mad Max-
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Re: Transmission Slipping 3-4th gears

Post by roadrunner »

kwalsh wrote:No codes. The CC went from a noticeable (visual & noise level) rpm drop to maybe a 200 rpm drop. I thought nothing of it, other than, "maybe I need to do a transmission flush".
If you're talking about a 200 rpm drop on lockup that's all mine has ever done and I don't have a programmer but do have wait4meperformance computer. The rpm drop has not changed with oem to performance computer change. The rpm drop is significantly larger on 3-4 shift however.
2001 CC LS, pewter, stock, 4.3,Wait4meperformance, CFM throttle blade, Helix throttle body spacer, 4spd auto, 3button electric 4x4 shift, heavy duty factory suspension, Bilsteins, 1" rear wheel spacers, skid plates.