More stuff on swapping a 4L60e for a 4L80e

[Peter D. Hipson]

Whoa, this is getting long... Bear with me... <g> 

At 08:43 PM 3/14/99 -0700, you wrote:
>I've got my tranny rebuilt and installed by around 3 o'clock Sunday
>afternoon.  $298 in parts and about a day and a half labor.   What a pain
>in the butt! 
>
>
>After reading the service manual, the main electrical connector on both
>trannys is the same.  However, the 4L60E has 2 more wires than the 4L80E.
>(The connector has lots of empty pin holes)   The 4L80E also has a
>secondary speed sensor unit, which would require running two wires up to
>the computer, that my wiring harness doesn't have.

The second speed sensor is the TISS (Transmission Input Speed Sender).
Rigging a cable would be trivial, connector (I've the GM P/N, it runs about
$18) and a shieled single pair cable are all that's needed.

>
>That was my next question.   After comparing pinouts on the 4L80E equipped
>computer vs my 4L60E equppied computer,  the 4L80E has perhaps 2 wires
>different, and the addition of 2 more, where my harness has "empty" spots
>on the connector.  So, are the computers really different, or do they just
>not hook up the wires that would go to it?   

The computer for the diesel is very different (different connectors). 

>I know the calpak would be
>different, and perhaps that's the only difference?!?   Would they really
>make different computers for such a slight change and not enable/disable
>via sw?
>
>
>>>The 4L80E uses a different flywheel and torque converter. I'm not sure
>
>>>whether the crankshaft end would need to be reworked to mate to the 4L80E.
>
>The 4L80E would require a different torque converter from my 4L60E, but
>that's not a problem, as I don't use the stock converter anyway and would
>buy a higher stall after market unit.    The flexplate is engine dependent
>and not tranny dependent.   I'm not running the one piece real seal
>crank/block anyway, but a gorgeous Cola Crank with a 4 bolt splayed cap
block.
>
>
>The hardware to mount the tranny is of little concern as I consider that
>the easy part.   I'm just worried about the computer crap.   Mainly because
>I've gone thru about 150 eprom burns to get my engine dialed in to my liking.
>
>
>I would rather have beefy parts, rather than one that lasts a year.   I
>found my old receipts and the last tranny build I had to do was on April
>4th.  Almost 1 year.   If  you guys would like me to take some pictures of
>the parts that failed, and the clutch size differences, I think you'd be
>amazed at what a piece of crap the 4L60e is.   The 4L60e should NOT be in a
>1/2 ton truck -- maybe a S10 or camaro, but defintely not in something heavy.
>
>As far as the costs for rebuild, all I have to pay for are the parts, as I
>do the rebuilds myself.  (Which is both good and bad sometimes -- good on
>the wallet, bad as a pain in my ass! :)
>
>
>I'm not sure how I could fool my stock computer into thinking there's no
>tranny hooked up if I were to use an aftermarket kit.

Use the code for a manual shift setup? That's what I'd do, if I were
controlling the transmission with a second computer. 

>
>If I have to buy a new computer, I'd assume I'd want one for a '95 with a
>350 and a 4L80e.  My current chip code was BJYM.   I have massive changes
>to the engine management part that I'd hate to do over.  So, is it possible
>to copy the engine calibration stuff over to a new chip via a range of
>eprom addresses,  and merge it with the tranny stuff?

Should be possible. 

>
>Some people have asked my for my BJYM code, and I'd be more than happy to
>share it.  I can also post my current code that I'm running with my engine
>setup.    I've done all my mods thru MasterTune software that's supposedly
>specific to my chip, so I don't know how/what/where to modify stuff in hex
>for different chips.  
>
>Is there a master list somewhere that somone has compiled with hex
>addresses so I know where to put stuff?   Also, when I've tried editing in
>the past, the chip wont run as I don't know how to compute the checksum --
>so I loaded my hex edited file in MasterTune and resaved it and it computed
>the checksum for me.
>
>   If anybody knows how to "hack"  MasterTune to see if it will really do
>all chips or what, I'd sure appreciate it.   The software is in two parts,
>engine and tranny.  Before the sw can be used to look at your chip, you
>must first put a "secret" code into your .bin file, as well as know the
>secret 4 digit password, which makes for a pain in the ass when you haven't
>used the sw in 6 months.
>
>Finding the original BJYM code will be a task, but I can upload my current
>config asap -- just tell me where.  Also, not sure if I should post the
>MasterTune sw or not?  (good/bad?)  I paid nearly $600 for it, and if
>someone could help modify it so it will do 4L80e stuff, I'd be more than
>happy to upload it.
>
>Thanks for all your help,
>
>Doug Bazarnic
> 
>
>
>
>
Thanks, 
        Peter Hipson (founder, NEHOG)
        1995 White NA Hummer Wagon