Hello

3 months ago i have pumped more than 5k USD to my 4L60E. I have replaced original 3-4 drum to Sonnax heavy duty drum, replacing what was needed and recommended by sonnax, pistons, springs Raybestos GEN II Blue frictions. With 1.56 mm steel plates i have been able to put 9 frictions in it. There are lot parts i have reolaced to make this transmission immortal. I have installed performance transgo kit to the hydraulic governor. All was assembled with new OH kit. Yesterday i took my car for short ride using snowless weather and +4C temperature. The car was stood 2 months during the new year, christmas and my trip to mexico. During this ride i was noticed that this jerking on 4th gear. Condition in 10% of the accelerator pedal pressed, rpm 1300-1500 and 50-60 Mph. I dont have any ideas on this because It was happen before disassembly of transmission and have returned fast. Thi could be a splice pack on the rear conected with the frame located in the rear left compartment? What could it be? I have replaced also to new a brake band drum and band drum, and EPC electrovalve. Should i replace 3-4 and TCC electrovalves?

Any ideas what to check and replace prior damaging my new "immortal" transmission?

 

Not sure on what's causing this, however definitely interested on what you find out as I'm in the middle of a secondary performance build and the last link will be my OEM 4L60E A4.

Did you perform most of the work in rebuilding your stock transmission with the Sonnax parts? With $5K invested, did you consider a fully rebuilt transmission from RPM or another manufacturer? An RPM Level VII goes for $5200.

 

Get it on a rack and check the trans fluid level. Yea, 5,000? Yikes. An RPM level 5 fully built is less then that and they could have installed it and tuned it by now for less then 5500. I think there level 5 is like 3800, and probably suits most people’s builds. Check that fluid.

 

Hey! Im from Poland. You must know that i had to pay for sonnax drum of 3-4 rd gear 1250 USD on summit racing, but finally when you add handling additional 200 USD and Duty 2% and VAT 23 % = totally i had to pay 1890 USD, then GEN2 raybestos blue 250 USD, Converter rebuild 250 USD, misc parts, 1500 USD = OHK, valves, shift kit (transgo), Metal pressure accumulator, pistons, springs, metal plates for frictions,etc, Total labor was 800 USD. Where dismatle and installation of the gearbox = 400 USD, transmission rebuild labor 400 USD, totally i have count 20500 PLN 1USD = 4.027 PLN => 20500 / 4,027 = 5090,6 USD. You have price for the ready upgraded transmission for 5k USD = > price for me c.a 5500*1.02*1.23 => Price of tranny with handling*duty*VAT (tax) = 6900 USD.... But you know i have considered to buy, i didnot realise finally to pay this price for rebuild. And i have bought the parts by myself, not by my mechanic.

So im little nervous when this transmission is not running well.

Yes sonnax was 3-4 drum, piston, spring, etc, whole parts within drum 3-4 and kevlar brake band (band was similar price to the borg warer - 10 usd of the difference). i dont count earlier upgraded planetary gearsets, Raybestos GEN2 Blue frictions, unnamed 1.56 mm thickness plates to fit 9 instead of 7 frictions. EPC Valve - i did not replaced valves. And the price to buy them is 1599 pln => 397USD in PL (borgwarner).

Corvette is let's say bit exotic car in PL, is not easy to see those cars in th city. Even i can say if D.Trump (and what he says, he does) will raise the duties for EU, EU probably wil do the same for him, so the corvette parts will be more expensive.

And believe me but if i lived in the USA, i would definely choose the version of the tranny rebuild by recognized companies, you have mentioned of.

- Have mentioned of oil level. If i remember i have put to the transmission 10 liters, 10,5qts of 6HP oil. THe transmission is let's say new so i have decided th change oil type. It have ATF properties but it have similar viscosity with low and higher themperatures. I will check its level definely this weekend. This was also my first thought.

 

Moved to C5 Tech for more assistance.

 

Could be an engine misfire type problem.

 

Hello, there is no DTC from a PCM in DIC, misfiring can occur but with a dtc within 0,2 sec of DTC flag. Common DTC with misfire are check emission DTC's. That is definely something with gearbox.Clutch slippage but 3-4 th? or a lockup? Before rebuilt i have seen 1680 DTC related to the TCC valve. After rebuild it was not shown anymore. Today i have visited my mechanic, he will check oil quantity with which he fill up the tranny. Anyway thanks for suggestion. I will check it during nex weekend.

 

If it is doing this in 4th gear with the torque converter locked it could be due to random misfires. These misfires don’t set the check engine light typically.
Anyway, if the pcm sees these it will unlock and lock the torque converter. Resulting in a jerky feeling.

Us hotrodders experience this when we add a cam and or a lighter high stall torque converter. Not sure if your car is modified.

The cure is to turn off the misfire detection in the tune.

 

Hello

It does on 4th gear while lockup is engaged. Especially on fast curves with speed c.a 60 mph, last time on the straight roads, when accelerator is barely pressed.
I can tell you problem was present before rebuild of the tranny an i got sometimes 1680 DTC - that's concern TCC solenoid. After transmission rebiuld was ok for first 2-3 rides, and started again. Im using true Iridium spark plugs by NGK /LPG no.5, but im running only GAS RON 95. No LPG installation present. As they says LPG is good only for a gas stoves.
I did not cammed engine and i use factory stall (2025 rpm) torque converter with only kevlar lockup friction.

So i try to change the spark plugs, the wires i have done custom dia. 10 mm wire with a silicone shielding, stainsless steel outer spring - those are specially resistant to a high temperatures and salty water. An i had to pay 25 USD for a set, here in PL.

Have another question - it is also possible that it could be accelerator's pedal potentiometer? I could be wear of TPS? You have info how long these parts lasts?

I have replaced in my RLaguna V6 having 300 k km on it. Corvette has 278kkm. So maybe also is a time for this?

 

I'd listen to Ron, and try eliminating the misfire detect. Process of elimination, one thing at a time. Ron knows a lot about these cars, especially the tuning....

 

Hello

I have lifted up my vette and check transmisison oil level. I have added 2qts of oil....and then tranny works fine. I wonder only for how long. I saw also some leak on through the new pan gasket. I must fix it using a cork gasket. The paper ones are shitty.
I will let you know after some time if everything is ok.
Thank you for the suggestions.
Also i will replace for new NGK spark plugs, i have bought yet.

 

Two things:
Per the service manual. The trans fluid level can only be checked when the fluid temperature is between 86° F - 122° F.

2. Check the functionality and lock and unlock speeds (MPH) of the torque converter clutch.

 

I think you answered your own question. Add 2 qts, all is good. But now there's fluid leaking from the pan gasket. Leak enough fluid, trans gets cranky, and won't work right. There's a specific procedure on C5s you need to follow. Time for the factory service manual, and no more guessing at fluid levels. I changed my fluid and filter myself@100,000 miles. It isn't that difficult, but you need to know the procedure. If you try changing the fluid yourself, in case you miss this part, DO NOT SHUT OFF THE ENGINE while checking the fluid level, or you'll get a red bath. IMHO, if 2 qts fixed it, it was down more than 2 qts.....