YAMAHAGUY

iTrader: (6)

I stumbled across this link after a bunch of back and forth with 60 vs 80:

4L80E Transmission Swap - GM High-Tech Performance Magazine

This link says you can just buy the harness from PCM of NC harness. Their harness is just two connectors(pictured). Compared to the frost harness, the frost harness looks like a full kit. What is the difference between the two? I know I can save a lot money just doing it myself, but I would rather just buy a harness, not because I like to waste money, but because its piece of mind for me.

PCM of NC 4l60/70 to 4l80 Conversion Harness

It says they replaced the yoke from the 27 to a 32 spline, I thought this was only required for the 4x4 trannys.

They said they didn’t have to shorten the driveshaft, but if the 80 is longer I don't know how this is possible unless its a judgement call or something. Granted this was in a Avalanche, but I don't think that would matter. I mean who would want an Avalanche :-0

They also said the 4L80E had a shorter 1st gear and I thought a lot of people were saying the opposite and 1st was taller and more sluggish and the 4.8 would struggle running this tranny behind it.

What did you do for a flexplate? They didn't mention using a flexplate to go from 60 to 80 as I've read the difference in hole pattern, spacing, and strength is different.

They mentioned fittings for the cooler lines to be extended, is this correct and how did you make a proper realiable leak free extension?

What is up with the differences here? Can someone talk about their experiences?

George C....

I reused my driveshaft and just bought the swap yoke

For harness i picked up a pigtail from junkyard

If your truck is a 4l60 i would just repin and add the speed sensor

YAMAHAGUY

iTrader: (6)

Good to hear!!! I like that you got to reuse your driveshaft.

I would plan on getting the 32 spline yoke and some new u-joints would probably be a good idea.

I understand that you would repin and as VSS but, I would rather just plug and play. I have better luck with that.

What did you do for a flexplate? They didn't mention using a flexplate to go from 60 to 80 as I've read the difference in hole pattern, spacing, and strength is different.

They mentioned fittings for the cooler lines to be extended, is this correct and how did you make a proper realiable leak free extension?

George C....

Repin is easier then a new harness Imho

You can use a 60flexplate if you get a 60/80 converter

I have a TCI one

My transcooler is different then most, i went from 4l60 to t56 and now 80e......

My trans cooler is mounted under bed and uses -6 AN hose

YAMAHAGUY

iTrader: (6)

How would repin be easier than pushing a connector together?

Ahhhh, that makes sense with a converter.

I will probably do the suggested Tru Cool deal.

Why do you have 6 AN hose? Is this easier for you since its flexible or just becasue of mounting location and going from T56 to 80E?

George C....

repin is just moving 2 pins into another location

I had no trans lines so I was starting from scratch, Tru-cool is fine and mounts nicely up front, that wasnt the option for me So -6 was what i chose

03sierraslt

iTrader: (22)

I've seen issues over the years with the conversion harnesses, none in particular. Never seen a issue from a proper re pin. Just food for thought.

GMCtrk

iTrader: (27)

I've been running a conversion harness for years without any issue. I got it dirt cheap new off tech years back, otherwise I would have repinned. Plugging in a connector is easier than repinning.

YAMAHAGUY

iTrader: (6)

You make it sound so simple, but re-routing them, messing with a connector that might not come apart easily, me making a bad connection are all bad reasons for me to repin, getting something backwords or those little pin connectors get screwed up(which need some special crimping tool or something).

1. On the instructions to repin the pic of the engine harness to transmission connector end view doesn't show the "U" as referenced,

"Remove pins S (WHT) and U (BRN)"

there is a "V" pin location, but no "U".

2. I'm a welder not a solderer :-), so Alternative 1 is out

3. Alternate 2 sounds like a better option, but will removing from Pin 2 and removing white wire from Pin 79 and connect to Pin 2 position sounds good but I'm thinking that would litterally be a strecth for the wire to go to the other side of the PCM.

4. I really don't like the idea of connecting new pins to the location 22 and 23 from the AT ISS. Do I need to get a new VSS connector? Will it come with the correct pin/connectors to put into the PCM. Is there enough wiring to go from the PCM to the connector?


These are my concerns and it doesn't seem that easy to me to just repin. I am just very cautious on wiring and stuff that controls a lot of stuff

George C....

It is that easy and simple

Simple as 1-2-3