My brother has a stock 94 Z28.

it had a blown up transmission when he bought it. we put in a used stock one, and it lasted ~10k miles before it broke.

we decided it would be best to get a rebuilt transmission, as he plans to put some mods on the car. the transmission was supposedly built to handle "500hp" ....

the new trans went in with a used neal 3500 stall converter, that came out of my friends daily driver. i know for a fact there isn't anything wrong with it.

the guy that built it said "take it easy for the first couple of up-shifts and down-shifts. make sure the fluid correct, and then it's good to go" .....

within the first 200 miles we put on an aftermarket trans cooler, running inline with the stock cooler. at this time the fluid looked perfect. it's been daily driven and went to the 1/8th mile track once.

according to what he's found on here, it also had a problem with the converter not wanting to stay locked up at 40 to 45mph. we havent been able to find a fix for that yet, he just avoids driving at those speeds...

now at 864 miles.... it's slipping and the fluid looks & smells burnt.

bascially.... i don't know much about automatics. i need some opinions on what failed, and if it was the builders fault or not.

if it was the builders fault... i need some help on what to tell him, so that he can't weasle out of fixing this. i have yet to talk to him, but i want to be prepared.

thanks in advance.
chris

 

of course its his fault. Just answer everything he says with IT has 800 miles on it and its broken already there had to be something wrong with it. Also take the trans cooler off. He will try to blame it on a modded tranny and that you messing with it on your own is the reason it broke. Yeah it sounds stupid but believe me alot of places would try to use that as an excuse.

 

dude i just installed a fresh gm rebuilt trans in november.... along with used neal 3500 and it started slipping at about 1000 miles.the trans was good upon dissassembly. All hard parts ok clutches looked good.

The sprag came apart in the converter metal EVERYWHERE... your on borrowed time with that converter..

BTW this converter worked fine in my friends impala before i used it...


I just did DIY overhaul and a B&M 2400 holeshot and fixed me right up

 

Problem more than likely has come from not properly flushing the stock cooler. from here you more than likely have filled your transmission with all the metal fragments from the previously stated bad transmission, could possibly be fixed by geting about 3-4 gallons of fluid removing the return line at the trans running a rubber hose off of that line into a 5 gallon bucket, jacking the rear of the vehicle up to get rear tires off of the ground being sure to secure the vehicle and make safety first!!!!!!!!! remove dipstick place funnel in it crank car put in drive run approximately 2-3 gallons of fluid through the trans while running through the gears, while constantly keeping an eye on how much fluid has come out and how much you have put in, both need to coincide. after you have gone through about 3.5 gallons of fluid shut the car off and hook everything back up, do not forget to recheck the fluid level. Oh yeah you need a buddy or 2 to accomplish this feat. Good luck and godsspeed

 

If the fluild smells burnt the trans and or converter has issues, Now sincce you said it has problems with lockup ,First I would remove the inspection cover and look at the flat face of the converter. Kook for a discoloration ring in the paint , If its there this is likley the source of your burn smell. I would also pull the pan and see just whats in it and let us know ad go from there.There are many possible reasons for a failure. Could be the trans was built inccorectly or a part coul have just failed. But then there are reasons with the 4L60E that come from the car that can cause it to fail also. Known causes there are OVER OILED AFTERMARKET AIR FILTERS contaminating the MAF sensor. With cam and heads installs you can get the TPS range off and this may cause stacked shifts and damage, The big question is before the failure how did the trans perform? what did the shifts feel like? Reguardless of the reason a good shop will likley fix the trans but it is important in anycase to figure out the cause.

 

Why do you guys go anywhere else. You should really check out threads like this, before buying a 4L60E.
https://www.camaroz28.com/forums/sho...d.php?t=568826

You should NEVER install a used converter in front of a rebuilt transmission, though.

A 4L60E NEEDS lock-up to keep the 3-4 clutches alive. The lock-up clutch in your converter may have had an issue that caused the unlocking condition that led to the transmission failure.

Frank
CPT

 

No offense to the guys at Performabuilt (I'm simply not familiar with their reputation), but I don't know why anyone would take a 4L60E to anybody but CPT. Frank's reputation is awesome, and his prices are too.

 

Frank if you keep teaching people about the failures and fixes of the 4l60e, your gonna have a bunch of protege rebuilders giving you a run for your money, lol.

 

LOL...Fortunately, it takes more than a bunch of good parts and a little advice. There's even other shops that copy our build sheet, but still can't get them right. You don't have to look very far to find one, either.

Besides, I'm not just here to make money. I'm a real car guy, so I know what it's like to find help when I need it. The reason we build our transmissions for the prices we do is because we also realize what it means to get the BEST of something for a good price. The reality is, you'd have almost as much in parts (retail) as we charge to build one. Remember, a simple little mistake can ruin a bunch of good parts.

Like I said...We're racers. We have a '93 Z, and a 10 second '70 Camaro. You'll find many, many posts in other areas of this forum that I've subscribed to/started. Our understanding of not only these transmissions, but about the cars, and the racing end help to make us better 4L60E builders.

Frank
CPT

 

yeah, thanks. i probably would have read it, except that post was made about 4 YEARS after mine.