D110/LS/6L80 Owners: Ratio Question!

Mattarm

Well-known member
I am right at 2200 @ 70 in my 110. 5.3/6L80E with 1.2 TC, original 3.54 diffs on 256/75/16 Goodyear Duratracs that sit right at 31"
 

MountainD

Technical Excellence Contributor
I built my 6.2l 6L80E / 354 did, 33” rubber, with the 1.2 lt230 and I’d go 1.0 if I did it again.
 

w2hx

Member
Callsign: W2HX
I built my 6.2l 6L80E / 354 did, 33” rubber, with the 1.2 lt230 and I’d go 1.0 if I did it again.
Great info. Just the feedback I was hoping for. I feel very confident now to swap out the 1.222 with a 1.003 which I've seen advertised on ashcroft.

Btw, I've also seen ashcroft had a 0.90 ratio set for the lt230. They say it is for diesels, but it wasn't clear to me if that is because the typical defender engines don't have the power to handle it, or if there is something mechanical about the 0.9 that prevents it from working in other applications. I'm using the markiw adapter between the 6L80 and the lt230.
 

Napalm00

Technical Excellence Contributor
I talked to a buddy and the torque converter lock up in the transmission is controlled by the internal transmission controller. The software that Nick supplies with the adapter harness should automatically enable it in sixth when not at wot
 

w2hx

Member
Callsign: W2HX
I talked to a buddy and the torque converter lock up in the transmission is controlled by the internal transmission controller. The software that Nick supplies with the adapter harness should automatically enable it in sixth when not at wot
@Napalm00 -might you know what the symptoms are of a torque converter not locking up? I would imagine maybe it is somewhat like a slipping clutch where the RPMs might rev, but the vehicle doesnt go any faster? Any info appreciated.
 

Napalm00

Technical Excellence Contributor
A scan tool can tell you if it's attempting to lock or not. You're going to have to talk to whoever did your wiring and controllers

Lots of good videos on YouTube on how to tell if a torque converter is locking or not. You will also get excessive heat in the fluid
 

w2hx

Member
Callsign: W2HX
A scan tool can tell you if it's attempting to lock or not. You're going to have to talk to whoever did your wiring and controllers
ok thanks. I have the OBD port and a scanning tool. Do you think it would set the trouble light (the little light next to the OBD port?) Maybe that is the equivalent of the check engine light? That light is not illuminated. Can this rule out the TC not locking up? Or must I dig further?
 

Napalm00

Technical Excellence Contributor
Can't tell you man I don't know how your truck is wired. You've got a lot of digging to do

A very basic OBD reader will not be able to tell you. You're going to need a legit scan tool
 

w2hx

Member
Callsign: W2HX
Did you ever figure out your diff ratio ?
Hi to all who helped on this thread. As was suggested earlier, I took a tach (Simpo with NIST cert, a few years out of cal) and I measured the following:

Truck TachSimpo Tach% diff
1000​
1000​
0%​
1500​
1450​
3%​
2000​
1860​
7%​
2500​
2343​
6%​
3000​
2800​
7%​

So clearly, part of the mystery why I am producing so many RPMS at 70 MPH is explained here. A fellow poster with a similar set up as mine said he was doing 2200 RPM @ 70 MPH so I may only be off by 143 rpm. And given the vagaries of trying to keep the tach in the truck steady, I'm probably quite close to 2200. Basically I know believe I do have 3.54 diffs, not 4.11 diffs as I originally thought. As another poster said, a 1.667 tcase plus 4.11 diffs (if they had been 4.11s) would have been strange and I think I agree.

Ultimately, I believe what I will do is swap the 1.222 tcase gear with 1.0 gear. This should drop my rpms about 500 to around 1,800 which sounds much better.

Thanks to EVERYONE who helped me with this question. Great forum.
73 Eugene W2HX
 
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