I'm starting this thread so I can share my ongoing transmission experience with the everyone. I'm hoping that my course-of-action will lead to a better option than rebuilding or replacing a 4T65-HD Tranny.

The first part of my odyssey is here: https://ls1tech.com/forums/ls4-front...yesterday.html

For those of you that haven't followed this, here's a quick story what me and my '06 Impala have been through:

In April of this year, the local Chevy dealer rebuilt my tranny under the GM Certified 5/100 warranty. This was done because the torque converter clutch came apart, and the material that contaminated the fluid wiped out the 3rd gear clutches. The car had 58,000 miles on it. A couple of weeks ago (22,000 miles later), my wife noticed that, when slowing down to a near stop, then accelerating again, the car would sometimes freewheel (as if it was in neutral) and not accelerate, only to slam into gear and go a second later. We took it to the dealer, and the intermittent problem showed up for them, too. So, they're putting a GM remanufactured tranny in it under warranty.

That's where we are now. The tranny is being installed today and I should have the car back later on in the week.

My concern now is, how long until this one has a problem?

Well, I've had several converations with Dave @ TEP, and based on his recommendations, after I get the car back and establish that the remanufactured tranny is working right, it will go in for some upgrades. Dave indicated that, since the trans will be basically be new, then it won't need a complete overhaul to be upgraded. So, he has recommended the following upgrades that should prevent the most common problems we see in these trannys:

Upgraded/Rebuilt Valve body & spacer plate: This includes some machine work, as well as all new solenoids and valves. The modifications should prevent some of the other common problems like harsh shifts.

Sonnax Converter Relief Valve: This valve bleeds off over-pressure when the torque converter clutch is engaging (lock-up). The factory valve bleeds off pressure at too high of a threshhold, which, over time, destroys the TCC. This is what caused my trans to fail the first time, as well as many other people on this board. The Sonnax valve has lower threshhold that doesn't overstress the torque converter clutch.

Seal Kit: This kit contains the long style lip seals that prevents issues like converter oscillation, and slow gear engagement when cold. We also think that a leaky seal is causing the issue my tranny is seeing now. This type of seal design is supposed to last a lot longer than the stock shorty seals.

The interesting thing that I've learned in talking to Dave is, GM made a bunch of compromises in our trannys so that they shift smoothly. When you couple that with the fact that LS4 engine is at the outer limit of what a 4T65 can handle without mods, it's no wonder the problems are so widespread.

These parts, along with the needed replacement spacer plate, are coming from TEP. I have TransGo shift kit sitting in a box that and will be installed when the other parts get here from Dave. The total cost of the stuff from TEP is about $405. My buddy's tranny shop will handle the work and is charging $400 to R&R the trans, and another $200 install the valve-body, shift-kit, and tighten up the 2nd and 3rd gear clutch clearances.

So, for around $1000, I SHOULD have a transmission that won't be giving me anymore trouble, but who knows. This is the most cost-effective setup me, as I only have a mild bolt-on car that isn't really beaten on but sees a ton of highway miles. I could have sprung for a TEP Street/Strip Trans, but the cost of the tranny with shipping and installation would have been around $2250, which is out of my budget. What I hope this will give me is piece of mind knowing that my trans is no longer a ticking time bomb.

I know this solution won't be for everyone, but for some who are having problems but not seeing material in the pan or if you're not having any problems yet and don't want to worry about them in the future, this could be a lower cost alternative. Also, if you're making big power or your animal behind the wheel (Travis), this may not be for you.

Anyway, I plan on using this thread to document each step in this project and will report the results, good or bad.

I just want a trans that WORKS!

 

IF you have the money can plan on continuing to add to your car, performance wise, go all out. You know.... just in case.

 

Its just his DD,he has the GNX for the performance...

 

That's interesting to know. Compared with our '95 Z28 (automatic), the GXP shifts extremely smoothly. I really prefer a harsh shift that kicks under hard acceleration like the Z28 does.

Are there currently aftermarket upgraded transmission for our cars that handle the power better? If so, what are our options?

Transmissions are too complicated for me to pretend to know anything about the bits and pieces. Seems like it'd be easier to purchase a brand new upgraded one when the old one goes bad.

 

Sorry if i missed it saying it was for DD purposes only. The reason i said that is because after only a two and a half months i was already grinding the input shaft.

 

Hope I didn't come off like a "Dick",just thought you saw his sig...My bad ,I member you tellin me your not on all the time...you might have miss Mike's other threads,about his tranny problems...

Vectus you got your tranny threw TEP?

 

No no not at all. i did, and saw that he had it tuned, didnt know if he was going to go further than that. Yea i sure did miss it, and i decided to throw in my .02 either way because of what was happening to my input shaft in such a sort time.

Yes sir, i did.

 

I too prefer a shift you can feel, and these mods will definitely help with firmness.

You can buy an upgraded trans from TEP, but it will cost $1650 to start, plus shipping. Obviously, if your tranny dies and you need one installed anyway, it makes sense to go the TEP route because a GM Goodwrench reman costs about the same.

And whether you do a full tranny swap or what I'm doing, you'll need a mechanic if you're unsure of how to do it, so it really just comes down to whether your trans is in good shape or not.

I wish I had a GNX! I just have to settle for the GN!

Thanks for trying to keep my thread straight, Dom!

 

Well, just got a call from the dealer and the car is ready. I'll be picking it up this afternoon and hoping that everthing was done right.

On a separate note, my "spare" trans is now on it's way back to TEP in Indiana as payment for the mods I'm buying. Hopefully, I'll have my new valve body and soft parts in the next couple of weeks.

 

Right on Mike glad to hear everything worked out in your favor.Yeah my bad,thought you had the GNX but you still have a gem in your hands.

 

I have a couple of questions on the 07 SS transmission...

first, does anyone make a higher capacity oil pan?

second, When is converter lock up supposed to occur?

Jim

 

Well, I got the car back yesterday. New trans shifts okay, but the new converter seems looser than the last one. The result is even sloppier feel in town and higher trans temperatures, especially when the converter is unlocked.

I'll be driving it around this way until my valve body shows up, which hopefully isn't anymore than a couple of weeks.

 

I think there is one out there, but supposedly, it doesn't fit real well and leaks.

I think lock-up occurs in 3rd and 4th around 45 MPH at cruising speeds.

 

LS1,

Do you have another trans. coming from TEP? I love mine! From 1st to 2nd if I am on it she'll break the tires completely loose. I only have done that once and haven't done that again... lol... Do you have a shift kit too? I have a TEP Precision TC (stock stall) that is like 150.00 or 175.00 (can't remember) and it works great! On a 50 degree day my trans. doesn't see over 152 as a temp. What's the trans. temps. at now?

-Mike

 

If I remember right, 210 is normal operating temp for our cars according to the owner's manual. I believe it also says if it's above 220, that's not normal. Mine is usually between 195 and 210 according to the DIC. On a hot trip during the summer, it was at 220.

 

Glad to see you back on a trans thread where you belong!

I don't know if you remember, but I had my trans rebuilt by the dealer earlier this year, and my trans temps went up about 10 degrees across the board. Well, it died again so the dealer put in a remanufactured one and a new converter. Now, the trans temp goes up even more, especially when standing still. I saw it climb from the 160's to 186 last night just sitting in a drive-thru. Even on the rebuilt original, it only got that hot on long grades in the summer. Oddly enough, when cruising at higher speeds with the converter locked up, the trans actually runs cooler. I saw 135 this morning on a level road in 55 degree temps after seeing 160 on a hill.

Since I already have a basically "new" tranny, I'm getting a TEP valve body and adding a shift kit. My buddy's shop is also doing some modding of the clutch clearances. I talked to Dave at TEP several times about this, and for my application and use, he thinks it's the right way to go.


I think the highest I've ever seen is about 208, which was last summer, going up a 7 degree grade. Normal for me with the cooler (and before the remanufactured tranny)was about 165-170. Normal when it was totally original was about 145-150 with the cooler.

 

Totally normal. Less heat is generated while locked as opposed to all the friction producing heat while the converter is slipping. The higher the stall the hotter the fluid will get.

 

Actually, I didn't explain myself correctly. The old tranny ran cooler with the converter locked, too. The thing is, it would run in the 140's-150's in the same situation that this new one ran in the mid 130's.

 

LS1,

Do you still have the trans.fluid running through the radiator? If so, try just running it through just the cooler and also you can put in a 160* thermostat and get a tune to turn the fans on earlier. This will do absolute wonders for the transmission. Come to find out on my last build the person putting in the input clutches put them in backwards. This was why my trans. ran at 244* right after it was put in the car and it only took 2 miles to get that hot. Good luck with the build.

-Mike

 

Hi Mike,

The radiator is still looped into the trans fluid circuit. When the rest of the work is done, the radiator's trans cooler will no longer be used. I've gotten lots of advice to bypass it, and that's what I'm going to do.

I've never thought of going to a cooler t-stat on this car. Where is it and how difficult is it to change?

Interesting to know what was causing those high temps in your old trans. I always guessed it was the converter. Sucks that it was someone else's carelessness that resulted in you having to do it again.