4th Gen 4 Life

On my 94Z it only has 1,3 and reverse. 2nd and 4th seem to be gone. As ive been researching usually when the sunshell breaks you usually loose reverse also. I have read up on it being the 2-4 servo on the side of the tranny? My plans are to replace 2-4 servo and replace both 1-2 & 2-3 solenoid? Does this sound like im on the right track? Also no slipping. When i put it manually into first it seems i have more power starting off rather then starting from over drive position on shifter? Any thought? Please share and thanks for any help in advance.

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PA94Z

There is no reason to replace the solenoids. There is no 2/4 solenoid, and having both fail in some way at the same time is very unlikely. With no 2nd or 4th, but reverse is OK.. the 2-4 band is not applying. There are two servos that apply the band - 2nd servo, and 4th servo. They attach to the same apply pin, but have there own apply circuits. In order for the servos/seals to be the cause they would both have to be broken/leaking. Again not likely.The band could be the issue, but I would think you would have had some indication it was going before it happened.

I would be looking at potential wiring issues if the mechanical side checks out. I believe you can air test the apply circuits for the band after dropping the valve body. I don't have my manual on hand, but will take a look later today and get back to you.

Injuneer

Let's move this to the "Drivetrain" forum

4th Gen 4 Life

Thanks for the info. That does make sense. Is the band a major internal fix or is it something i could replace fairly easy with a tranny manual? I plan on just pulling the whole trans and replace front and rear seals and new torque converter(2700 stall). Im also going to add shift kit so i can do a air check while at the valve body. Any other info i need to know?

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12SCNDZ

The 2-4 band is either burnt up or broken. A 4L60E can fail in several ways. It can rip the anchor lug out. It can rip the apply lug off, or it can rip the band in 2. The ends are spot welded on.
Is the fluid dark or does it smell burnt? This would indicate it has burnt the band. If the fluid still looks good, it's most likely broke the band.


Frank

4th Gen 4 Life

I just recently purchased the car. But fluid looks clean but i dont know if they changed it out or replaced filter. Also while i have had the car it showed no signs of it going out so my guess is the band broke. Also what are some of your favorite rebuild parts frank? I know i plan on building it a little past stock. Sunshell beast, corvette 2-4 servo... etc
How are alto parts? Also just a guess but the car seemed to be built a little with cam and reworked heads ported ans such and typical bolt ons. so im taking a ballpark figure of hp to be around 300-400. So a massive performance rebuild would not be necessary. Thanks for all your input and help.

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12SCNDZ

The 4L60E had many design flaws that need to be addressed during a rebuild. I, personally, haven't seen any good "kits" available for rebuild parts. All fall short in one area or another. We source our build parts from many different manufacturers in an attempt to use the best of everything. The only thing Alto makes that should be used in a 4L60E is their 2-4 band. All LT1/LS1 F-Bodies come with a "Corvette" servo. They're not really a performance part. There are better servos available. There lies a great example od using parts from different manufacturers. Fairbanks makes a better 2nd servo than Sonnax, but Sonnax makes a better O/D servo than Fairbanks.

Frank

Injuneer

Thanks again Frank. I move these posts from other forums, because I know we can rely on you for feedback.

12SCNDZ

No problem at all, Fred. I try to jump in and help when I can. Unfortunately, I believe this particular problem is going to require a rebuild to fix it.

Frank

PA94Z

Well it looks like you got solid advice here from Frank. If the band simply broke, and did not drag or contaminate the fluid with metal I would put a new stock band in it until you decide on a full rebuild. It isn't very difficult and does not require special tools to do. The trans will need to be out of the car, and you will need to remove the valve body, pump, and servos. A good factory service manual should be purchased. I got mine on ebay for $40..

By the way I still have not looked at my manual to see if you can air check the band. I don't have it with me.. but will let you know when I do. It has been awhile since I rebuilt my trans and can't remember. I did use a "kit" that had everything including modified spacer plate and customized transgo parts for the valve body. Good parts are one thing, but the hydraulic circuits need modified along with it for the trans to hold together. Mine has done well so far. The big problem for someone who wants to do the job themselves is the tools. You may spend a few hundred just in tools to do the job.

12SCNDZ

Technically, you can change the band without removing the valve body or servo. You only need to pull the filter and TCC solenoid out of the pump and pull the pump out. You can pop the band off the anchor and pull the drums out with the servo still in and the VB on.
The problem with just replacing a band is that it won't fix all the other weak areas or design flaws with the 4L60E. These transmissions have atleast 6 different flaws that contribute to premature/repeated 3-4 clutch failure.
Yes, the tools to build one can get expensive. In most cases, the tools will cost more than having someone build it.

Frank

4th Gen 4 Life

I have a manual floating around somewhere? As for tools i have a good friend thats a machinists and could make the tools. I have never rebuilt a transmission before but im very confident due that im a smart phone technician. To be honest all the small pieces in the trans remind me of all the small components in a phone.

Brian

94 Z28 4l60e. Reworked heads ported and polished. Cam 3" catback flowmasters. And common bolt ons.

4th Gen 4 Life

Alright sorry to dig this back up but looking to get some expert(frank) advice on my current decision. As we already know the condition of my tranny. I really need to get by with a mild rebuild on the trans. I figure upgrade some of the weak points of the transmission. I think i can reuse some parts and get by. My plans are to replace sunshell, bands, 2-4 servos, and pistons in the valvebody. Can i get away with replacing just this or what other things are a must tearing into the trans that deep? Seals, springs..etc also what are some preferred bands that you all like to use? Thank for all the help and support you all been giving me.

Brian

94 Z28 4l60e. Reworked heads ported and polished. Cam 3" catback flowmasters. And common bolt ons.

Any help or advice i give is my 2 cents and is based on my experience with the F-Bodies. As always seek professional help for certain problems.

xsk5

update?

i have no second gear but overdrive still works on a 95Z. i'm hoping i can change out something simple until i either swap to T56 or get a more robust unit.

4th Gen 4 Life

I just purchased another trans. Upon removing the old trans I discovered it was the wrong trans for my car. It was a 95 f body 4l60e with TCC/PWM. No doubt the 2-4 band was broke but I think your issue is something different. In my lack of experience with these trans I would take a guess at it being a valve body issue or servo issue. Your first best bet would be to have your trans pressure checked. You can buy the gauges fairly cheap or have a local trans shop check it for you.

94 Z28 A4 known mods... reworked ported heads/intake. Cam, 3" cat back flowmaster. unknown PCM tune. still researching car. ...

1990 RS HO 305, TH350(shift kit). 4 barrel carb, Cam, Long tube headers.