3.42 Gears and TruTrac

Hambone

Always learning
Jan 24, 2016
572
0
16
Florida
Hey Mark how do you like 3.42s and 6th gear on the highway?
Trying to figure out if I want to do one or the other...possibly both to my Lly :confused:
 

MarkBroviak

DMax Junkie
May 25, 2008
2,075
361
83
Danville Indiana
Hey Mark how do you like 3.42s and 6th gear on the highway?
Trying to figure out if I want to do one or the other...possibly both to my Lly :confused:

I want them in my wife's LMM if that tells you anything. You will have to adjust tcm tuning for them but if you have torque then they are awesome.
 

prostreeter600

Street rodder
Jul 18, 2010
893
7
18
Dallas Tx
Mark , what has to be adjusted on the TCM . I ask cause I put 3.42s in mine and haven’t adjusted anything. What do they affect other than the speedometer reading? Mine seems to drive and shift fine .
 

MarkBroviak

DMax Junkie
May 25, 2008
2,075
361
83
Danville Indiana
Mark , what has to be adjusted on the TCM . I ask cause I put 3.42s in mine and haven’t adjusted anything. What do they affect other than the speedometer reading? Mine seems to drive and shift fine .

Depends on the setup but the shift points themselves because you are changing how you are loading the motor because the rpm difference. Full throttle shift points usually go off the rpm set point but the part throttle stuff is where you can really notice the differences.
 

MarkBroviak

DMax Junkie
May 25, 2008
2,075
361
83
Danville Indiana
Worse part about this is you can't even get these gears anymore:mad: They quit making them a while back and I don't think you will find them anymore anywhere.
 

Ne-max

I like turtles
Nov 15, 2011
3,361
64
48
Lincoln, Ne
I just ordered a set. My supplier shows Yukon having like fifty two of them on hand. But they have let me down on stuff like that before also.
 

prostreeter600

Street rodder
Jul 18, 2010
893
7
18
Dallas Tx
I can honestly say that I can’t tell the difference from the 3.73s to the 3.42s . I just hope it helps at the track for a better 60’,better ET and higher MPH.
 

TROJAN366

Gold Rush
Jan 13, 2012
2,474
1
38
MASS
I can honestly say that I can’t tell the difference from the 3.73s to the 3.42s . I just hope it helps at the track for a better 60’,better ET and higher MPH.

I bet there is a bigger difference between the 5 and 6 speeds. I noticed a nice drop in rpms on the highway.
 

MarkBroviak

DMax Junkie
May 25, 2008
2,075
361
83
Danville Indiana
I just ordered a set. My supplier shows Yukon having like fifty two of them on hand. But they have let me down on stuff like that before also.

I just googled it and you are correct! Called Summit racing to verify and they have them in stock so I'm gonna have a word with my sales people...:mad:
 

Hambone

Always learning
Jan 24, 2016
572
0
16
Florida
Isn’t the only difference between 3.42 and 3.73 the pinion gear has one more tooth?
So could you just get away with replacing the pinion?
 

S Phinney

Active member
Aug 15, 2008
4,011
18
28
Quncy, Fl
Isn’t the only difference between 3.42 and 3.73 the pinion gear has one more tooth?

So could you just get away with replacing the pinion?



Gears are done in sets. Both pieces need to be replaced or you probably won’t like driving the vehicle around much for the noise.


Sent from my iPhone using Tapatalk
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,120
4,863
113
Phoenix Az
Isn’t the only difference between 3.42 and 3.73 the pinion gear has one more tooth?

So could you just get away with replacing the pinion?



One tooth, thickness of ring gear, diameter of pinion, and pitch of the gears. It’s not that simple or everyone would do it for sure lol
 

jpowel29

Member
Feb 1, 2008
780
0
16
Bentonville, Arkansas
Any noticeable differences between the Yukon gears vs going back with the AAM gears - as far as quality/durability and gear set-up?

I've run the Yukon 4.56 and 3.73 gears in other set-ups. Was thinking about getting AAM if I decide to do this swap.