evilstuie

Note: I (mrvedit) moved this from the PCM Tuning section to the Auto-Trans section as it mostly discusses early 4L60E issues.

Hi Guys,

About 9 months ago my transmission in my 1985 Pontiac TransAM died and forced me to take the car off the road. As I needed to take the transmission out I decided then would be as good a time as any to also replace the tired 350TPI motor with something with a bit more punch..

I've got a 400SBC block +40thou that was been prepped and ready to build, and the rotating assembly is at the shop now along with the 24 tooth reluctor wheel and should be balanced ready to go by Friday. I've got a set of AFR Eliminator heads that have been heavily ported and smoothed and opened up to 220cc intake ready to bolt on, and running a Extreme Energy 270HR cam, and currently 2.73 9 bolt diff. The top end is a HSR EFI intake with 30lbs injectors and lastly now running a 4L60E transmission from a 95 Corvette.

I did a bit of research on the OBD2 swaps, and after a mistaken purchase of a 98 firebird PCM(3812) and harness, with some more research, found that the VT2-VY Holden commodore LS1 cars also used the 0411 PCM.
I bought a VX HSV PCM and harness and am now ready to install everything and get started, once I re-pin the 3-4 ignition and injector pins to match the SBC firing order.
I also purchased a AVT-852 cable which is on its way to me to use with EFI Live, but once that arrives, I have a few questions as to what to do next:

1) I've been told an LS2 6.0 truck base tune would be the best option to start with, where would I find the file?

2)Will I be ok to use the transmission parameters for the LS2 truck tune file, or will I need something to use the 95 corvette transmission with that tune?

3)Would I be better off keeping the VX commodore tune file and copying the fuel/spark etc tables from the LS2 tune file to ensure the harness pin order is correct?

4)Should I install the MAF sensor with the car, or find a mafless tune to use instead?

5) Is the base tune going to be ok to run the motor in, or could it cause damage to the motor during the run in phase?

6) Can you change the VIN# in the PCM by flashing it, or is it not possible to change it to match your EFIlicence /calibration file?

I'm sure there's plenty more questions but these are the main ones I can think of at the moment.
Any help would be greatly appreciated.

mrvedit

Please confirm that this is a non-LSx SBC motor that is being retrofitted with a 24x reluctor and presumably with a crank and cam sensor?
And you are going to run LS1 coil packs and no distributor?
If all that is true, I am inclined to ask why didn't you just get a used LS1 engine?

I do notice one problem - an LS1 PCM will not properly control a '95 4L60E as the TCC (lockup) and 3-2 downshift solenoids are incompatible.
Only a '95 PCM can control the odd-ball '95 4L60E.
A LS1 PCM will work properly with any '96 through '07 4L60E/4L65E/4L70E.

evilstuie

Yes, n0nLSx SBC motor, 24 tooth reluctor, efi-connection timing cover and sensor, and vortec distributor for cam sensor, ls1 coil packs as well.

I thought about the LS1 motor, but didn't want to have to mess around with cutting into the k member, making/buying new transmission bracket, running additional return line, find a compatible sump etc.

I already had the heads and intake from when I wanted to do a 383 build, and didn't want the added job of engineering certificate (required in Australia for any non-factor engine change) added to the list of to do things.

In the end I'd much rather a torque monster 400 than an LS1, at the end of the day, it was cheaper to use the parts I had.

I swear, with all the reading I've done to get ready for this project, I never would have thought the transmission would give me the most trouble.

Does it cost GM a fortune in ink cartridges or fonts to change the model number of a transmission when they change something, or they just like confusing the f*ck out of everyone using the same "4L60E" designation for 50 variable models?

evilstuie

Is there anything I can do to the 95 4l60e to fix this, i.e, swap in a 3-2 solenoid from a later model, or something?

There aren't any tune files that can modified, or custom OS to be able to control it with the 0411 PCM?

evilstuie

Are you sure you aren't thinking of 1994 4L60E transmissions?
This says 94 wont work, but 95-97 are the same.

T700r4 wont work because the TCC wont work at all withoutr a controller
I can't use 97+ without some modification to fix the gap difference
And with the bulk of sbc x24 conversions using 0411 no-one else seems to have so much trouble with transmission slection.


https://ls1tech.com/forums/conversio...s-4l60e-s.html

mrvedit

First you need to make sure your trans has "PWM" stamped on the front of the pump.
If not, there is no chance of it working.

The '95 had a PWM 3-2 downshift solenoid and the '96+ have a on/off 3-2 downshift solenoid. This is according to the ATSG 4L60E Update Handbook page 52. While I have no personal experience with this year, I have posted this a dozen+ times on this forum and no one has ever disagreed and several trans experts have confirmed it.
I don't know if the LS1 PCM will throw a code or the trans will have excessive slippage or harshness during the 3-2 downshift. The '95 PWM 3-2 downshift solenoid has 10-15 ohms of resistance. The '96+ 3-2 downshift solenoid has 20-31 ohms of resistance, perhaps enough difference for the PCM to detect. Not sure, but as long as you have a "PWM" on the pump, you might be able to switch to a '96+ or later valve body and separator plate (and gaskets) to solve the 3-2 downshift problem. Just changing the solenoid is not enough. You might need a new wiring harness too as the connector appears to be different.

GM certainly should have changed the model number in '98 when they introduced the 300mm LS-style 4L60E because the LT-style and LS-style don't even physically interchange.

evilstuie

Thanks for that, I'll check tomorrow and confirm the PWM stamp

evilstuie

So...
No "PWM" on the front plate...
Where do I go from here?

You mentioned the ohms of resistance of the solenoids being different. IS it possible to adjust the resistance by placing a resistor in the wiring harness to sort of modify the difference onto the solenoid or something?

mrvedit

While most '95 4L60E are "PWM", I suspected not all were and you are confirming it.
The PWM (Pulse Width Modulation) refers to how the TCC (Lockup clutch) is controlled by the PCM. The pump, valve body and TCC control solenoid are completely different between the older non-PWM and the PWM transmissions.
I don't know what happens if a LS1 PCM tries to control a non-PWM transmission during converter lockup. Few try it because it doesn't sound likely to have a good outcome.

Sorry, but I really think you should sell the '95 trans and buy a newer '96 or '97 LT-style 4L60E. Actually LT-style (298mm input shaft) 4L60E were made for many more years aftr '97 and were used in V6 vehicles, C5 corvettes and some trucks. The newer and the lower the miles the better. A V6 doesn't matter as the internals are the same and just as strong.
Unless the '95 was recently rebuilt, it likely has many miles on it and is on its last legs anyway.

evilstuie

That sucks then!

Here in Australia, there are no LT 4l60e's available, nor trucks. We have Holden commodores and that's a bout it.
I was very lucky to find the 94 LT transmission on ebay, my only other option is a LS1 transmission which I've heard has a gap/issue matching up to a sbc.

In one of the other forums, someone was talking about a transmission setting in the tune that you could set to 100% in order to send a TCC lockup to a non-PWM transmission in order to make it work.
Would that work?
Another quick question I can't remember the answer to, can the 0411PCM control a 4l65E, and does the 4l65e (4HZD) have a 4 bolt or 6 bolt output shaft?

mrvedit

Sorry, I just don't know if such a tune change would work with a non-PWM trans. You will still have the 3-2 downshift solenoid issue to deal with too.

GM actually makes a kit to bolt an LS1 trans to an LT/SBC engine. It is about $200:

#19154766 Adapter/Spacer for bolting LS trans on LT engine

I already answered your 4L65E question above.
A LS1 PCM will work properly with any '96 through '07 4L60E/4L65E/4L70E.

The 0411PCM will even work with a 4L70E which has the input speed sensor; it is simply ignored.
Somewhere around 2008 and definitely by 2009 GM made another incompatible change to the 4L70E, eliminating the 3-2 downshift solenoid, replacing the manifold pressure switch with a physical switch, different valve body and more. The connector is also keyed differently so that it cannot be accidentally intermixed. GM really should have changed the model number for this too. A actually made a 2010 work with a 0411PCM, but I had to install an '06 valve body and harness.

My concern is that you will spend a lot of effort making the old '95 trans work, and then your stout engine will shred it.

evilstuie

What about this one?
It says 7HDD which I'm assuming means its a 97 model?

http://www.ebay.com.au/itm/vs-commod...item1c4fc1f2f8

or better yet:
http://www.ebay.com.au/itm/191536671...%3AMEBIDX%3AIT

I'm assuming if the transmission still has the single piece casing I won't need the adapter?

I did a quick lookup of PWM functionality, and so long as the PWM max threshold is set to 100 that would work. Alternatively I could make a circuit to detect the pwm signal and send whatever the correct voltage is to the non-pwm solenoids to get functionality out of the current 4L60E I have....maybe?

mrvedit

Yes, either one should be fine. I would ask the seller for a picture of the front of the pump to be absolutely sure it is a PWM. Any of the 1-piece units will not need the adapter.
A rebuilt is a good idea with transmission of that age!!

Adapting a SBC to a 0411PCM already has enough complexity; why add a incompatible marginal trans to the mix.

evilstuie

Got a response back on one of the boxes.
Green connector plug, 12 pin.
Do I need 13 pin to work with 0411?

mrvedit

According to this diagram a 12 pin connector does not have the TCC "Feel" solenoid which is part of the PWM setup:
http://www.msgpio.com/manuals/mshift/wiring.html

So, Yes, I think you need the 13 pin connector.
Perhaps the years and models are a bit different in Australia.

evilstuie

This has been a friggin nightmare!
The more information (or misinformation) I get the more difficult it is to determine what will and wont work, or even what the outcome of using it would be.

Ok, 13 pin connector - 24203060 case, 1996 - 6WHD
...Do we have a winner?

mrvedit

Yes, that sounds very promising.
Please have the seller send a pic of the front of the pump to confirm the "PWM".

I don't understand how the '97 could have had only 12 pins; I'm thinking it was rebuilt as a '95. Seemed cheap, maybe that is why.

This probably should be in the Auto-trans section, but I have been the main 4L60E contributor there for several years.

evilstuie

I'm a little more worried now.
My 95 non PWM transmission has a purple connector with 12 pins





Are we certain its incompatible?

evilstuie

Quick checkup again, so long as the transmission code has a "6" at the front of the 4 digit code, it will work?
The ebay item I put a bid on is a 6HBD not 6WHD, will this still be ok?

mrvedit

Here is what I learned from Chuck at sponsor FLT:

"There was no TCC solenoid in the VB in the early 93/94 on-off units (12 pin connector). Beginning in 95 they added the (pwm) solenoid to the VB thus the reason for the extra wire (13 pin connector)"

I'm sure the LS1 PCM will complain about a 12 pin connector as one solenoid is missing.
Since these old transmissions may have already been rebuilt with various parts, make sure the pump says "PWM", the connector has 13 pins and the first digit of the 4-character code is at least a "6".