The way this is worded may come across as slightly misleading. The GM High Tech Magazine 94 Formula did a 24x conversion and reported that the 94 4L60E was working fine after some tuning. I had no specifics, but assumed the tuning had to do with the TCC lockup table. I only passed on this info...that the conversion claimed to be a success with the 94 4L60E...and they claimed to have had plenty of road time.

We've been keeping our eyes open for an early 4L60E core to build and use in Bill's 33 ****** (24x SBC). That should provide some familiarity and shed some light on the issues with the 94-95 transmissions. I've spoken with several knowledgable people about this and keep getting inconsistent information. The guys who seem to know what they're talking about have been rather firm that it's just a valve body, solenoid, and internal harness swap.

One of the first 24x LT1 conversions is in an early Chevy pickup with a 95 4L60E. It's a daily driver. Lookup the screen name "schwoch1" and ask him what he did to his transmission. I seem to recall that he changed the internal solenoids and harness...but I don't recall mention of a valve body change. I could be wrong.

 

So, in order for me to swap to a 24x, I have to swap to a 4l60e made for the year 96-97? I'm sure it's the same internals, maybe just swap soleinoids, electrical harness in the valvebody, or something? I mind as well install a th 350 or 400 with t-brake, if a different trans is needed for the swap.

 

as said earlier, you must swap the valve body (with electronics), harness, front pump, and seperator plate

 

Well here I am....... here is what I did, 8,000 trouble free miles (and still many more to come) with no issues. Trans works great. I have found that most of the misinformation floating around came from transmission shops who are used to doing 'stock' rebuilds. I used to work for one of them for a short time, and trust me, that is their 'CYA' statement anytime they see something they do not like on a customers vehicle!!!!
What I did on my '71 GMC was use the 4L60E that came with the engine I had. It was a '95 vintage 4L60E that came out of a Impala SS. It had a 'horrible' rebuild done by Dr. Transmission (whoever he is, should have his tools taken away from him but that is a different story!!!). I went through it, rebuilding it as stock, no shift kit, goofy servo's, etc. Just used a wide band and a new reverse input drum and treated it to all the same thing that I normally do when I rebuild a transmission. I had to change the wiring harness to the '96 Up harness and I had to use the '96-up 3-2 downshift solenoid (later on-off style, not the earlier PWM style).There were no valve body changes, pumps or other voodoo things, just a harness and solenoid, that was it, no drama, no bullshit, just easy stuff. I had to add a speed sensor to the back of the transmisison to get a speed signal for the PCM, but there again, I used a kit from jagsthatrun to make the speed sensor work for the PCM. http://www.jagsthatrun.com/Pages/Spe..._Reluctor.html
I just bought the reluctor wheel from jagsthatrun and bought the speed sensor locally. I used a 700-R4 output shaft in my transmission so I could use a normal cable driven speedometer also with my transmission as my original transmission had no provisions for a speedo gear on it. Again, no drama, no bullshit, it just works!
I have driven my truck for the last 8,000 miles with '0' issues regarding the transmission. Granted, my junk doesn't make 500 HP or have blowers or turbo's hanging from it. It dyno's at a nice solid 310 HP at the crank. Again, no drama, no bullshit, it is stone reliable!!!
Now if this were a '93 or 94 unit, there is a little more to do. From what one source told me, you jam the 3-2 downshift solenoid into the valve body (there is a hole there) and change the harness. I have not personally tried this, but I cannot see why it would not work. If you understand how a 4L60E works, you will see why!!!!
I hope this clears up any problems, my opinion is, if you are toasting clutches and other realted soft parts..... get someone else to build the transmission. Stop blaming the PCM and get someone else to build your transmission. Lotta people out there are self professed experts, but when it comes down to it, some of them couldn't make it at AAMCO or Cottman, so they decided to build HP automatic transmissions to make ends meet. Not trying to **** in anyone's Wheaties, again, just my opinion!!! I just hope it helps someone and doesn't start a pissin contest!!!

Mike

 

That trans was actually eventually changed out, not sure on the reason for the change though.


Im not pulling this info from nowhere. I seemed to be the first to really test it, cause EFI didnt really tell me either way if it was going to work

RPM told me that a 94 4L60e could not be controlled by an LS1 pcm. They said they knew what had to be changed over and relyed the info to me. I changed the parts that I previously mentioned and have had ZERO peroblems. The others transmissions were burned through within 300-400 miles.

 

From what I understand, Mike at EFI connection really did not know either, so why are you trying to fault his kit when the company specifically stated he was not sure if it would work with your transmission? What people fail to realize, is with **** like this there is a little bit of trailblazin that needs to be done occasionally, sometimes at the expense of parts. There are some people that really cannot handle any type of trailblazin I have found over the years.
Mike

 

how am I faulting his kit in any way. I stated that he didnt know and that is accurate. Im not knocking him or his business in any way. You need a reading comprehension check.

I have posted numerous times just to warn people and tell them the simple things that need to be done to convert their early year trans.

Go "trailblaze" elsewhere. I feel like I have been nothing but help to people when it comes to this issue.

 

i would be royally pissed if I was ThreeHonks, I think he's doing a great job of relaying strictly the facts.

I don't think R&D ignorance is acceptable when you're talking about a 2k dollar OEM efi swap kit. And if they failed to properly R&D their kit to find the limitations, they shouldn't let their customers guinea pig, or "trailblaze" or whatever you want to call it. This ain't space flight or brain surgery...

 

thanks wicked. I dont want anyone spending the $1000's I did in transmissions... on top of the ~$1000 I paid for the swap.

I still have the all the emails between me and EFI asking if I can use my '94 60e with this swap. basically they told me that if you tune it, it will be good to go. WRONG.

I left an email with them and a voicemail (just informing them on my findings), not only did I not recieve a response back, let alone a "thanks" or a "sorry"

I still think they have a good product and I wouldnt hesitate to use it again, just was bad luck that I had to be the guinea pig. A little bit of communication goes a long way, a simple "thanks for telling us your problem/finding" would have been nice

 

Are you kidding me? Then where do you draw the line? How about the many, many, aftermarket timing sets with variations of original crank and cam sprocket thicknesses? Should R&D involve calling Summit and say, "I'd like to order every timing set you have for the SBC and LT1 engines."?

It's an LS1 PCM swap, not an aftermarket ECU. It's GM's controller that does what it does. And in this case, it does not control a 94-95 4L60E. Saying, "We've not yet used a 1994 or 1995 4L60E.", is a pretty honest and fair caution before proceeding with the installation of the product.

You're ignoring the progression of a product. People get interested and knock on your door before prototyping is even complete. I recall saying to many for nearly six months, "no, not yet". So you have those who "couldn't wait" and may have had a few bumps along the way...which is not even hinting at intentions of anyone being a "guinea pig". Man, it's frustrating to even see someone suggest that. And with the exhaustive amount of parts out there, who could possibly keep track of what the aftermarket has done to affect another product. As far as "bumps along the way" goes, so far the only problems have been related to some aftermarket timing sets, the early 4L60E transmission, and poor tuners.

Why is it that those who only care to criticize an LS1 PCM conversion keep arguing "2k dollar" and many who are interested save costs with used/alternative parts and do the conversion for much less? I can think of many DIYers who are under $1k by doing their own harness work, PCM, and ignition coils.

 

^ This. Like I've said in this thread (I think) and others, you'll spend upwards of $2K if you buy everything, brand new, plug and play, from EFI Connection. When I first set mine up, I sourced the harness (plug and play) and all sensors used, and the PCM and coils separately. I spent about $1,100.
Just because every single avenue hasn't been explored, this does not imply any ignorance or neglect whatsoever. If you had a product ready for market, but hadn't developed it for EVERY possible application, would you wait to release everything to the market? Hell no. You've gotta get into the market and start making money to support your business's growth and continued success, and above all, put food on the table.
They may have an application for the 4L60E someday, they may not. It's completely up to them.
Sorry for your rep being dragged through the mud, Mike. Thank you for your contribution to improving the LT1 market and providing a solid product.

 

Is this the external engine/trans harness? Wondering if its possible to swap out the 3-2 solenoid in a 95 4l60e with one from a 96 using a 95 LT1/4l60e harness that has been modified for 12200411 PCM. Wondering if you used the 95 LT1 harness or a completely new harness.

 

So as of now, you have to change out the valve body, 3-2 shift selenoid, valve body, spacer place, and internal transmission wiring harness to use the 24x set up? How much do you think this is going to run?

 

subscribing ... I figured I would run the 4L60 unlocked until I picked up a built 96+ 4l60e. I assumed it would bolt up and work fine since I ordered the harness with the appropriate connectors. I'm interested to see what others have done.

 

Wow this kind of went down a path with the automatics, but thats cool, no big deal

I'm planning on getting the kit, but am going to throw another opti at my car until I can afford the kit. I'm replacing everything on my suspension right now and can't afford to do anything else until this project is finished.

I'll probably just get everything from EFI, is there any type of discount if you get the complete package? Billet cover and possibly coil pack mounts

 

do a search on whats gonna happen. I have tried to post on this a lot but if you guys really think that its just a lockup issue (mine actually locked fine) then you are in for a world of hurt. bye bye trans

 

Could you either elaborate or give me an idea of what I am searching for? Do it in PM if needed.
There are a lot of people running 700R4, TH350 and TH400s behind LT1s, it doesn't seem to be that big of a deal.

 

To address your original question;

24x LT1 Conversion Package $525
Ignition Coil Bracket Assemblies $500
Used 95 LT1 Timing cover (with welded water hole) $30
Used 94+ TB IAC Housing and IAC $30
Used LS1 PCM - GM# 12200411 $100
Custom Engine Harness 93-97 $850

New LT1 Timing Set $85
New LT1 Timing Gasket Set $15
New LS1 knock sensor $45

Custom Spark Plug Wires $90
Tune $450 ... so far

Otherwise, it's just the same 'ol cleaning supplies, zip ties, tools and tubes of automotive gunk I have in my toolbox.

 

There will soon be a better option for the harness. A conversion of your existing harness will be offered, makig this much more affordable.

I have 200 in my coils, PCM, and front cover. By the time I sell my gm opti and new Dynaspark ill be comig out pretty good

 

those are all non electronic transmissions. the only 60e that can be controlled by a LS1 pcm is a 96+