black deception

I have a 4l60e (1993 model)that will shift from 1st to 2nd to third and try to find fourth but finds nothing and lets rpms go down while in fourth as there seems to be nothing there! If you pull selector lever into third though third is there!Now if you slow down and as the gears descend it will never go back to first gear again! It starts out in 2nd gear! If you turn ignition off for 10 seconds though it will find first gear again and process starts over as above?? Is there any chance that it can be the trans. pressure switch?? I have changed both solenoids and pulled valve body down to check for stuck valves and am at my wits end! Thanks in advance!! There was talk previously about a default in these trans referring to third gear!!! What is the story on this???

12SCNDZ

Third gear is "fail safe" in a 4L60E. This means that both shift solenoids are commanded "off". This can be caused by a code, or a loss of power to the transmission. Do you have any SES lights? Has the vehicle been scanned?

Since this is a '93 4L60E, I'm assuming it's in a truck, right? They didn't start putting them in the F-Body until '94. GM trucks have a problem with the ingition switches. When they go bad, it stops power supply to the transmission. We solve this problem by installing a relay to provide 12V to the "E" pin directly to the case connector, at the transmission. This fix saves you rom having to replace the switch.

Frank
CPT

black deception

I will ck this out tomorrow!! Thanks for the info! It is in a truck too! I will keep ya posted!!

black deception

Well i got it fixed today!! It was the 3-2 solenoid shorted out and putting trans in limp mode!! thanks to all!!

Performabuilt

That will do it , Glad you got it fixed

iscout62

Just stumbled on the thread from a google search, and this info is really helping me out with my first teardown of a 4L60E. I have two (2wd) 4L60's that are getting new (4wd) output shafts installed, for use in my LT1/4L60e Landcruiser. I'm lucky so far, as all I have seen in my transmission is some bushing residue. (crosses fingers)

BigBadBlack93Z

I'm about to start ordering parts to rebuild mine and after my last 700r4 rebuild I know what parts I want, just not sure if I need to upgrade much more. I'm looking for around 375rwhp, no nitrous, no slicks & 2800-3200 stall.

Right now its fluttering in and out of lock up and goes 4th to 3rd on occassion. 1-2 slips really bad under WOT, taking it easy all is good. I have not been driving it to avoid a major failure.
I want to go w/ Alto wide band, beast sunshell, art car input shaft reinforcement kit(a local guy machines these identical to the kit and they seem to work well, its just a 1/8" steel ring on the shaft).
Is there a difference in the billet servo's? I had a JET one and get them at a decent price but I see some other house brands listed places.
Does the 4L60e use the 3-4 plunger like the 700 for WOT upshifts?

Jason Dove

Overrun clutch burnt out on mine. So I did an M6 swap...

Frank89IROC

I have a 1994 Trans Am basically stock engine except for a Borla cat back exhaust & Moroso cold air intake. The car has 40700 original miles. The transmission shifts hard into 2nd gear almost as if someone hit my car in the rear, otherwise it runs fine. I've had to replace the tranny mount. I have no idea what is causing this. Anyone experience anything similar and what was the remedy?

slingshot

Took out 2 and 4 clutches in one day....i have the 93 4l60. Got it rebuilt locally for $1000 bucks....builder said the transmission was not in bad shape, it died at 83k miles. The car has been beat on its entire life as I know, the guy who owned it before me put the cam and boltons on the car, I have done some other small work. Too much horsepower for an old stock transmission..

joel322u

i HAVE A 94 Z28. AND I SEEM TO BE HAVING ISSUES WITH THE SOLENOIDS......

MikeGyver

My 3rd/4th clutch let loose a week after the turbo was installed although the stock replacement trans has been holding up fine for over half a year

Oh and the trans I swapped in had a bad TCC clutch solenoid, so I just swapped that over.

vanhalendlrband

I had a problem the second I got my 94 Z28 and they told me it had a rebuilt tranny.

My first problem was mainly in Overdrive with what was apparently a "vacuum" problem, just would seem to not accelerate if I stepped on it, espescially in Overdrive.

Then one day i heard a loud sound and after that I couldn't get into 3rd gear and up, only the 1st 2 gears and can barely get it into any gear now, not even 1st or Reverse which was a problem when it first broke.

I took it into a GM Dealership and the mechanic there didn't know what I was talking about when I mentioned "Vacuum hoses" that the other mechanic (which my dad whose a home mechanic knows quite well and trusts him with jobs he doesn't have the tools for) said he would have fixed for me no problem but I had to go back home, as I was out of town visiting my dad. Basically the GM Mechanic told me "Because it was rebuilt there's no way of knowing what was wrong with it to begin with and to rebuild it might be a lost cause."

Me and my dad have been working on this as a project for some time, we have plans to take it out and just get a new used 4L60E transmission, and i've seen a few come up for sale used, i've read that it pretty much has to be a 94-95 maybe 96 but definitely not 97 without upgrading electronic parts? I'm not sure if I have that right.

Any ideas if its something we can rebuild, was that GM Mechanic right or trying to get me to buy a brand new 4L60E?

I don't know if some of you remember I posted a thread years ago I think about a crunched Camaro that me and my dad have been slowly over the years been restoring back to original dimensions with the help of body mechanics and once we figure this tranny thing out we're going to install a brand new dashboard with new airbags, new front end pieces, and lights.

P.S. Another question I have is that I've seen 4L80E's around the same year up for sale, would that be a better transmission being that its heavy-duty, any difference i'd notice, need other electronic parts?

camaro81

The 4L60E doesn't use a vacuum modulator, that mechanic was on crack and likely didn't even look at the car. Some people modify a 4L60E to use a vacuum modulator, but this is pretty rare and leads to the transmission's death
If you're sure it's the factory transmission, just have it rebuilt. There are a few site sponsors that have a decent rep, just read some of the threads here and do a search on the company to hear from their satisfied customers. I'd recommend CPT, they build one of the strongest transmissions for the best price.
Really no reason to get a 4L80 unless your putting out like 1,000hp on a pure drag car that you still want overdrive on for some reason You would lose a bit of performance with the 4L80 over the 4L60

vanhalendlrband

What did they replace the Vacuum's with in the 4L60-E's? Sometimes i'd step on it in Normal Drive and it just wouldn't go I'd have to almost pump the gas, car would start to slow down. Stuff like that.