4L80E V 4L85E Transmission

Coupes66

Specialist
Dec 26, 2017
84
54
25
Ride
BMW 335i N54
I was wondering if someone could explain why only the 4L80E transmission is preferred for the N54 and not the 4L85E. From my research, it appears the physical dimensions and ratios for both are the same but the 4L85E can handle more power and torque. I am considering changing my transmission and therefore, I am considering all options. I know the powerglide would be the best transmission for the strip but I like driving mine around on the street as well and the overdrive would be ideal for this.
 
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Tiron

Lurker
Oct 10, 2018
23
25
0
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BMW 135i
My understanding is that the 4L85 is just a 4L80 with a slightly stronger input shaft and a 5 pinion planetary gear. They put it behind the 8.1, and the Duramax when used in vans (pickups got the Allison), where the standard 4L80 was behind pretty much every 2500 gas pickup since like 1991 (and also the diesels until the Duramax). I wouldn't put in the effort to try and find a 4L85 -- the 4L80 is already very strong and probably easier to find.

They are essentially the same trans, there is no reason you couldn't use an 85.
 

Coupes66

Specialist
Dec 26, 2017
84
54
25
Ride
BMW 335i N54
My understanding is that the 4L85 is just a 4L80 with a slightly stronger input shaft and a 5 pinion planetary gear. They put it behind the 8.1, and the Duramax when used in vans (pickups got the Allison), where the standard 4L80 was behind pretty much every 2500 gas pickup since like 1991 (and also the diesels until the Duramax). I wouldn't put in the effort to try and find a 4L85 -- the 4L80 is already very strong and probably easier to find.

They are essentially the same trans, there is no reason you couldn't use an 85.
Thanks for the info Tiron. I live in Australia so both of these transmissions are hard to come by.
 

doublespaces

General of the Army
Oct 18, 2016
8,939
4,143
0
AZ
Ride
2009 E93 335i
My understanding is that the 4L85 is just a 4L80 with a slightly stronger input shaft and a 5 pinion planetary gear. They put it behind the 8.1, and the Duramax when used in vans (pickups got the Allison), where the standard 4L80 was behind pretty much every 2500 gas pickup since like 1991 (and also the diesels until the Duramax). I wouldn't put in the effort to try and find a 4L85 -- the 4L80 is already very strong and probably easier to find.

They are essentially the same trans, there is no reason you couldn't use an 85.

Nice first post.
 
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langsbr

Captain
Apr 5, 2017
1,176
673
0
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07 335i 6MT e90
agree @AD-ENG still owes me $700 from almost 6 months ago and now cant even get an answer from him. I will be making a detailed post soon!

This is amazing its still happening. If he were a tuner, he'd been run off the platform long ago.
 
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Coupes66

Specialist
Dec 26, 2017
84
54
25
Ride
BMW 335i N54
What is the best Electronic transmission programmer unit for the 4L80E or 4L85E?
 

Coupes66

Specialist
Dec 26, 2017
84
54
25
Ride
BMW 335i N54
i was received a microsquirt from ade , says its the updated version aka the better one
Thanks Omar. I hadn't heard of the Microsquirt TCU before. Others that are available that I have found are TCI Shift Boss, TCI EZ-TCU and PCS TCM-2800 Controller. I will read up on all of these and see what users have to say.
 
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Coupes66

Specialist
Dec 26, 2017
84
54
25
Ride
BMW 335i N54
Does the floor tunnel require any modifications to fit the 4L80E transmission?
 

[email protected]

Lieutenant
Oct 19, 2016
534
404
25
NY & AZ
vadersolution.com
Ride
N54 135i & N54 335i
0E9F9D18-ECD3-4AAF-9803-A9679909CA16.jpeg
 
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Coupes66

Specialist
Dec 26, 2017
84
54
25
Ride
BMW 335i N54
Looks closely where the trans tunnel and floor meet on both sides
Yes I see it now. How do you find the Microsquirt controller? After looking at some of the controllers, I was leaning towards a TCI EZ-TCU controller. Is the Microsquirt easy to connect electrically to the BMW system?
 

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Lieutenant
Oct 19, 2016
534
404
25
NY & AZ
vadersolution.com
Ride
N54 135i & N54 335i
Haven’t personally used it yet but if it’s same as megasquirt then yea super easy stuff with live tuning and really nice data logging . Hopefully making adjustments will be as easy as it is on motor