4le90 vs 8le90 transmission behind LS?

[tower210]

Guys,

Looking at both these options. Currently 4.56 gears with 34" tires. 8LE has much lower overdrive that would put me in the range of 2100-2200 RPM at 75 MPH without a gear change (or bigger tires). I know the 6LE is much longer than a 4LE; but from what I have read the 8LE is shorter than the 6LE. The 4LE would leave me 2600-2800 rpm cruising; which feels crazy high for an LS that doesn't need that power at that rpm. Maybe that's what pushes me into new axles...

I know the 4LE would be much simpler from a computer standpoint; but if I go 8LE would likely have the OEM transmission controller.

I know there is $$ difference here; but let's pretend for now that isn't a factor. Which would you choose and why?

 

[mysunnshine]

The 4L80E will use an external controller if you run a LS that is newer than 2006. The 6L80E has the controller in the valve body and I'm not sure if that will be compatible with the pre 2007 LS based engines. The post 2006 engine controller will share information on the can bus that the 6L80E will need. Thy not just use a 4L65E? Do you really need a 80 series transmission?

 

[Grendel]

The 4L80E will use an external controller if you run a LS that is newer than 2006. The 6L80E has the controller in the valve body and I'm not sure if that will be compatible with the pre 2007 LS based engines. The post 2006 engine controller will share information on the can bus that the 6L80E will need. Thy not just use a 4L65E? Do you really need a 80 series transmission?

Not quite.

A 4L60E was used post 2006 and most PCM's will control 4L80E's, anywhere a 4l60E was used. Gen3/4 or 5 - simple wiring changes and a stock GM PCM.

Yes, there is a TEHCM (Transmission Electro-Hydraulic Control Module) in the 6L80E, but you also need a TCM module, that is normally included in the PCM, there are some stand alone TCM's out there. 6L80E is Gen 4 engine architecture and above. They all need to be on the same driver level: TEHCM, TCM and PCM.

8L90E has a stand alone TCM, and no TEHCM. PCM and TCM can be programmed to work together.

Guys,

Looking at both these options. Currently 4.56 gears with 34" tires. 8LE has much lower overdrive that would put me in the range of 2100-2200 RPM at 75 MPH without a gear change (or bigger tires). I know the 6LE is much longer than a 4LE; but from what I have read the 8LE is shorter than the 6LE. The 4LE would leave me 2600-2800 rpm cruising; which feels crazy high for an LS that doesn't need that power at that rpm. Maybe that's what pushes me into new axles...

I know the 4LE would be much simpler from a computer standpoint; but if I go 8LE would likely have the OEM transmission controller.

I know there is $$ difference here; but let's pretend for now that isn't a factor. Which would you choose and why?

What engine do you have now? What ECM and harness?

I didn't have any ECM or wiring for my CJ8 project, so I have a 2011 6L80E, with a Dana 300 on the back of it, in my Scrambler. I am using a 2007 LH6 engine in front of it.

Not sure a D300 will clear the shaft on the back of a 8L90E, as they're much wider.

I do have all the transmissions here, if you need measurements.

A 6L80E is not much longer than a 4L60E.

 

[Grendel]

I have pics of an Alpha 4l60E (they have clearance in the pan and valve body for a Dana 300 front shaft) and a 6L80E with a Dana 300 on it, somewhere... but here's some dimensions:

GM Transmission Dimensions

A B C D D E F G H Trans Model Bell Housing Main Case Case Extension Length to Flange Length to Shaft Engine Block to Converter Lug Length to Extension Housing Engine Block to Mount Center Line to Bottom Pan 4L60/70 2WD 6.941 15.421 8.909 N/A 30.975 0

paceperformance.com

In a nut shell: The 6L80E is much taller, but not much longer and it's narrower than the 4L60E.

I have both here, a 4l60E with clearance and a D300 as well as a 6L80E with a D300 on it. I'll be selling them both in the spring, since I have my trans and t-case in place.

 

[Grendel]

Not the pic I was looking for, but you can see the two:

G

Post in thread 'Bucket, the 1981 CJ8 frame off.'

Jun 13, 2024

Playing around with transmissions and t-cases today.
A 4L60E, with Alpha pan and valve body to Dana 300, with twin stick
A 6L80E with Dana 300 and JB Conversions 32 spline input. This is really the best fit, if you had a 5/8" thick clocking ring to make it flat. It bottoms out, .5" out.
And the case I am going to use for my 300, with LoMax gears, 32 spline inputs and outputs.

• Grendel

• 

 

[mysunnshine]

Not quite.

A 4L60E was used post 2006 and most PCM's will control 4L80E's, anywhere a 4l60E was used. Gen3/4 or 5 - simple wiring changes and a stock GM PCM.

Yes, there is a TEHCM (Transmission Electro-Hydraulic Control Module) in the 6L80E, but you also need a TCM module, that is normally included in the PCM, there are some stand alone TCM's out there. 6L80E is Gen 4 engine architecture and above. They all need to be on the same driver level: TEHCM, TCM and PCM.

8L90E has a stand alone TCM, and no TEHCM. PCM and TCM can be programmed to work together.


What engine do you have now? What ECM and harness?

I didn't have any ECM or wiring for my CJ8 project, so I have a 2011 6L80E, with a Dana 300 on the back of it, in my Scrambler. I am using a 2007 LH6 engine in front of it.

Not sure a D300 will clear the shaft on the back of a 8L90E, as they're much wider.

I do have all the transmissions here, if you need measurements.

A 6L80E is not much longer than a 4L60E.

You are absolutely correct with the information about the later useage of the 4L65/70 with the later LS based engines.

 

[tower210]

I have pics of an Alpha 4l60E (they have clearance in the pan and valve body for a Dana 300 front shaft) and a 6L80E with a Dana 300 on it, somewhere... but here's some dimensions:

GM Transmission Dimensions

A B C D D E F G H Trans Model Bell Housing Main Case Case Extension Length to Flange Length to Shaft Engine Block to Converter Lug Length to Extension Housing Engine Block to Mount Center Line to Bottom Pan 4L60/70 2WD 6.941 15.421 8.909 N/A 30.975 0

paceperformance.com

In a nut shell: The 6L80E is much taller, but not much longer and it's narrower than the 4L60E.

I have both here, a 4l60E with clearance and a D300 as well as a 6L80E with a D300 on it. I'll be selling them both in the spring, since I have my trans and t-case in place.

Thank you for all the info. I don't currently have any of the parts/pieces yet (except a 4:1 converted Dana 300); just starting to plan to make sure I get all the "right" parts and pieces. The 2" taller to centerline on the 6L seems like a really big deal; that maybe means the transmission is almost 4" taller; that seems like a deal killer in a scrambler.

It sounds like maybe I'm looking for a 4L60/65e and a clean gen 3 6L. My d300 leaks a bit on the rear seal (even after rebuilding). It looked like you mocked up an atlas there too? Did it not fit as well?

 

[Grendel]

Thank you for all the info. I don't currently have any of the parts/pieces yet (except a 4:1 converted Dana 300); just starting to plan to make sure I get all the "right" parts and pieces. The 2" taller to centerline on the 6L seems like a really big deal; that maybe means the transmission is almost 4" taller; that seems like a deal killer in a scrambler.

It sounds like maybe I'm looking for a 4L60/65e and a clean gen 3 6L. My d300 leaks a bit on the rear seal (even after rebuilding). It looked like you mocked up an atlas there too? Did it not fit as well?

It's not an Atlas, it's a TMI Dana 300 with 4:1 gears and 32 spline outputs.

I have a 6L80E behind my 475HP LH6 in my Scrambler, no issues with the height and I was able to pass a 1350 CV shaft past it. I am doing a 2" drop belly pan, more belly clearance than factory. Deeper 1st gear with double OD sold it for me. Put a good converter in them and they're solid for high HP.

I also have both an Alpha 4L60E and 6L80E with D300's attached, will be selling them soon. The biggest issue with a 4LX0e is getting the VSS signal the ECM needs. I use the Advance Adapters tail shaft housing for them.

 

[Grendel]

 

[Grendel]

That's a D300 on the back of a 6L80E.

 

[tower210]

Grendel, Thanks for sharing; I might be interested in one of those. What's the history on each. Have they been rebuilt? Or just pulled?

KK

 

[Grendel]

They're all rebuilt, with new / updated converters.

 

[Grendel]

I found the pic I looked for.

Alpha 4L60E on the left, 6L80E on the right. Bell housings lined up with each other. Also on the same dolly type, for height comparison.

No adapter on the 6L80E, it's how they bolt on, with a 32 spline input. Since there is a .5" gap, I use one of these with them, so you can clock them. https://www.jbconversions.com/products/dana300/plate.php - In my CJ8, I didn't clock it.

Alpha 4L60E has an Advance Adapters tail housing, with VSS in it. You can clock in 7 degree increments, but needs the drop for the driveshaft to clear the pan.

 

[Svarasv]

I found the pic I looked for.

Alpha 4L60E on the left, 6L80E on the right. Bell housings lined up with each other. Also on the same dolly type, for height comparison.

No adapter on the 6L80E, it's how they bolt on, with a 32 spline input. Since there is a .5" gap, I use one of these with them, so you can clock them. https://www.jbconversions.com/products/dana300/plate.php - In my CJ8, I didn't clock it.

Alpha 4L60E has an Advance Adapters tail housing, with VSS in it. You can clock in 7 degree increments, but needs the drop for the driveshaft to clear the pan.

Good info, I am in the process of replacing my TF727 with a 6L80E and I was wondering if the D300 will bolt direct. So I understand that there is no need of an adapter, just a clocking ring ?? Plus of course the 32 input on the tcase

 

[Grendel]

Good info, I am in the process of replacing my TF727 with a 6L80E and I was wondering if the D300 will bolt direct. So I understand that there is no need of an adapter, just a clocking ring ?? Plus of course the 32 input on the tcase

Correct, I used one of these:

JB Conversions, Inc.

www.jbconversions.com

He has a 32 spline input, too.

I have a t-case ready to go if you need it.