2020 hd

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,655
5,803
113
Phoenix Az
I wouldn't be, I've done some fairly silly things with mine and haven't burned up my clutches and I'm only at 1k ft lbs at the wheels. Mind you mine is just a modified 246 that came on half tons too, not purposely built like this one.

its going to make lift companies either fix the pinion angles they set them at or include new drive shafts though.
 

M.A.M.

Member
Jan 9, 2016
429
7
18
Ohio
Wonder how hot they’ll have to get before they’ll start back up by themselves to cool down. The 1st gen L5P cooling was impressive to begin with, sounds like with the improvements it should be even better.


Sent from my iPhone using Tapatalk
 

LikeABoss

New member
Nov 18, 2018
3
0
1
Sure I know they have some lower gears down low but don’t you think they have at least 1 maybe 2 final drive ratios higher than the 6 speed? I haven’t seen a final drive ratio chart if it is available yet. I suspect rpms will be way too low on 35s at highway speed and/or you won’t make it out of 8th or 9th.
 

Hoser

Active member
Jun 19, 2016
235
30
28
Farmington, MN
No they don’t. Almost identical ratio 6th & 10th. These new trannys don’t usually offer a significantly higher OD, it’s a larger gear spread that they are after. IIRC, in the new 10 speed, 10th actually is a tiny bit numerically higher than the current 6th, so actually a lower gear ratio. That could be because of the larger stock tires on the 2020.
 

Hoser

Active member
Jun 19, 2016
235
30
28
Farmington, MN
Here’s the ratios,

First number is the 6 speed the second number is the 10 speed.
1st 3.094 4.54
2nd 1.809 2.86
3rd 1.406 2.06
4th 1.00 1.72
5th 0.711 1.48
6th 0.614 1.26
7th 1
8th 0.85
9th 0.68
10th 0.63

R 4.48 4.54
 

Hambone

Always learning
Jan 24, 2016
572
0
16
Florida
Dude that thing is going to be a sweet tow truck!
Performance wise I don’t see it though
Way to much stuff going on to be able to click off consistent Et
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,655
5,803
113
Phoenix Az
6-9th will be real nice for pulling grades with a load.

ill bet this sucks pulls hills like a bat out of hell with those kinds of ratios. keep that truck right in its power band without revving the hell out of it.

now if they will make a conversion for older years.... :roflmao: :D
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,655
5,803
113
Phoenix Az
Dude that thing is going to be a sweet tow truck!
Performance wise I don’t see it though
Way to much stuff going on to be able to click off consistent Et

if you can get into the TCM and develop a skip gear tune (assuming it can happen on this trans), it may not be an issue. it would actually give you alot of possibilities to keep the truck in a good power band down the track but skipping useless gears due to the upped power.

skipping will depend on the internal design and how clutches are applied though.
 

2004LB7

Well-known member
Dec 15, 2010
6,952
2,130
113
Norcal
Here’s the ratios,

First number is the 6 speed the second number is the 10 speed.
1st 3.094 4.54
2nd 1.809 2.86
3rd 1.406 2.06
4th 1.00 1.72
5th 0.711 1.48
6th 0.614 1.26
7th 1
8th 0.85
9th 0.68
10th 0.63

R 4.48 4.54

Can you do this again adjusting for the new rear ratio?

I'm not near my computer to run the numbers
 

Hoser

Active member
Jun 19, 2016
235
30
28
Farmington, MN
Is this what you’re looking for?

1st 3.094 - 11.540
2nd 1.809 - 6.747
3rd 1.406 - 5.244
4th 1.00 - 3.730
5th .711 - 2.652
6th .614 - 2.290
R 4.48 - 16.710


1st 4.54 - 15.526
2nd 2.86 - 9.781
3rd 2.06 - 7.045
4th 1.72 - 5.882
5th 1.48 - 5.061
6th 1.26 - 4.309
7th 1.00 - 3.420
8th .85 - 2.907
9th .68 - 2.325
10th .63 2.154
R 4.54 - 15.526
 

2004LB7

Well-known member
Dec 15, 2010
6,952
2,130
113
Norcal
Thats it. Now we can see the actual final ratio

Looks like 9th is actually closer to our 6th