dr_cranii

Lately I have grinding noise like grrrrr-r-r-r-r (more like growling tummy) in the range between approximately 48-70MPH 200 miles after tranny rebuild. And this noise only appears if I hold gas pedal steady as soon as I tap on it noise goes away. Then comes back…

I rebuild my tranny approximately 250 miles ago. Changed everything… all clutches (3-4 clutch Z-Pack), seals, bushings, Teflon seals and even small seals on solenoids and cleaned everything. New transGo plate. All steel check ***** replaced with Torlon check *****. New kevlar belt. New pump. Plus some other super heavy duty bushings and wider sungear bushing. New TC. I have 9,5” 2600 stall TC. All valve body parts showed no wear.

Here are the symptoms:
1. Rapid temperature increase. 200 miles after rebuild.
After rebuild I was going to install additional oil cooler, but still can’t find correct fitting for radiator. For the first 200 miles my temp never went over 203F. Even though I have 9.5” 2600 stall torque converter without additional oil cooler. Then after 200 miles my temp started to increase rapidly and sometimes reaches 230F-240F well I don’t drive with that temp. But one day was standing in traffic with 228F and couldn’t get off the road. Cumulatively I drove car with tem in the range of 210-228F maybe one hour over these 250 miles.
2. Something is holding car back on the highway.
After some time I have noticed that when I drive on highway with speed over 50MPH and if I’ll release gas pedal rapidly car will start holding the road with engine. I mean RPM won’t fall to 1000-1500 range. I don’t know if it is normal or not. This actually occurred before grinding noise. Well I took my dad’s Astro for a ride, it has same 4L60E and it is really hard to say if it has this “neutral” when you release gas pedal. If anyone notice that let me know if it’s normal, maybe It’s just me. But my MPG went down a little.
3. No Upshift 60-86MPH.
One day I was driving and road was clear no cops no cars.. so I floored it… and from 60 to 86 on matter of seconds with downshift, but as soon as it reached 86MPH my RPM was jumping from 5-6K’s and no upshift! I release pedal and tap on it lightly and I have it in gear.. I didn’t have a chance to accelerate more, but it was somewhere in 4th gear. Then I had a chance to test 2 more times. And same thing it reaches 86MPH and no upshift, just stuck in gear.
4. Sometimes on the highway it requires a little more RPM to make it move. I mean I don’t feel that it accelerates as it was. Gas pedal feels marshmallow a little on the highway. 50+MPH
5. Oil has a little of metal, but smell and color is fine. I used Dexron VI.

Well this is what I thought first:
I thought maybe because I rebuilt it and all the bushings are new it takes some time to adapt and some metal shavings are floating everywhere… and maybe they block way somewhere in TC solenoid. Then I thought maybe it is TC or TC solenoid. Or 3-4 accumulator piston that attaches to the valve body, or something that makes 3-4 clutch to not apply firmly. Cause with new seal it was very tight, but again it was working first 200 miles.

What went wrong? Is it in tranny or TC? Or maybe I messed up tranny with high temp? Sorry for long post.

kh400

There shouldn't be any metal in the new oil!!! Did you flush the integral oil cooler out when you had the trans out of the car? Very important. Sounds like it's on its' way out again to me. With a high stall convertor, an external oil cooler in MANDATORY!!!!!! I think you are going to have to pull it out and start from scratch. Good luck!

dr_cranii

Yeah I flushed my radiator with TransFlush and then with compressed air it was super clean.
But I didn't geat a chance to clean valve body and solenoids super clean. Some tiny metal shavings were there.. but everyone kept saying to me that oil will wash it off I would just have to change oil sooner.

My guess that this black tiny powder is what washed off from valve body and some from new bushings.. But it is just tiny amount.

I hope it is not clutches again. I always thought it needs more time with hight temp to fail.
Still have no correct fittings, none of the autostores and homedepos have correct thread..

bwiencek

Heat only comes from either excessive friction between parts or slippage of parts (i.e. converter or clutches - let's hope converter in this case...) The 'grrrr' noise I would think can be either front pump or planataries...

Are you sure you seated the converter in the pump properly?

Did you soak the clutches in fluid for at least 1/2 hour before assembling and check all the clutch pack clearances to make sure they're not too tight?

That right there might be a problem - the valve body has to be CLEAN - if even a tiny piece of metal shaving gets into it then it could jam up a valve and cause problems...

Pete K

I could not agree more.

dr_cranii

I had a DVD from www.4l60-e.com and I have checked everything and air-tested it.
Did soak clutches for one hour one day then 30 min another day. And before I closed up the pan I sprayed it all with ATF - maybe 1 1/2 quarts. Then added some in pump. so it was all in oil.

Clearances were according that video and paperwork I got with clutches and TransGo plate.

One thing though. When I installed "Double wide sun gear bushing" into sun gear that plugs into reaction shell. It was tight on the planetary. And when I air-tested assembled tranny. On one side it should've rotated in both direction and on the other in only one direction. Well it was rotating in one direction on both sides BUT if I would do it with pliers it would turn in both directions - like in video. So I disassembled tranny again and that reaction shell was really hard to turn, what I mean as I turn it clockwise it would turn the whole thing, planetary wouldn't rotate.... but as soon as I turn halfway counterclockwise and then clockwise it would be fine... That doublewide sun-gear bushing was tight.. so I was working it and spraying oil everywhere and after maybe 40 minutes of hard work it was ok. When assembled it - still hard to turn with "naked" hand. Dad said don't worry when you have 250 lb. of torque and everything in oil it'll be fine. And it was fine! For first 200 miles.

Yep, sure converter seated properly.. redid it 3 times Dude in video said to double check on this one. I quadriplechecked.

Could it be that shavings from new bushing got into valve body and messed up torque converter lockup piston or bore. That would explain why I needed ~3000 RPM on highway SOMETIMES.

Today as I was driving it was FINE. No noise at all..

But I still don't know if it's normal when I release gas pedal at 53 MPH and RPM stays at ~1900 then car slows down and as soon as it hits 44MPH RPM drops to ~1200. Corvette owners check it out when you have a chance. Thanks!

So for now first thing to do is to change oil and clean valve body? Maybe I should get some new pistons? Or is there anything else that should be changed mandatory with valve body removal?