thatcabledude
GOLD Star
Pfft, Aisin Seiki!You have the wrong transmission, you 4L80 is not geared for your set up, you can get some 3.54 gears from Australia or the Sumo with the over drive gears, you really should have used the Allison
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Need help finding taller gears (1 Viewer)
- Thread starter Drewthecarguy
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- Thread starter
- #22
Should have used the Allison? Don’t want to sound rude but have you put a duramax into a 80 series before?You have the wrong transmission, you 4L80 is not geared for your set up, you can get some 3.54 gears from Australia or the Sumo with the over drive gears, you really should have used the Allison
Duramax and stock axles lol why
thatcabledude
GOLD Star
You still running the factory t-case in your build?
pics and info of duramax swap lol
- Thread starter
- #26
My 80 series Duramax swap build
Hello all, I’m going to start a build thread here to show my progress on my current Duramax swap in my 94 FZJ80 Little history first, i bought this cruiser basically from the original owner with around 320k on the clock. But it was very well taken care and had almost all of its service...
forum.ih8mud.com
Ignore him. He’s a troll 99% of the time. His way or the highway. I for one like seeing your build progress. Tue last giy I saw with the dirty max had all kinds of issues with the Allison fitment.
Yes but that's downstream of my motor and upstream of my axles
Is the Duramax running stock programming? If so, it will feel terrible with 4.10's/33's.
Get some EFIlive action going on or atleast one of those TPS amplifier devices so you don't have to mat the pedal to get 2500 RPM and it will be fine.
Or go to 35's. That would put you same gearing as a stock GM pickup with the duramax.
Duramax swap is way too messy to ever appeal to me, but I am carefully planning a healthy and clean 12 valve and 6 speed Allison swap into an 80. My tape measure says it will fit fine with the right combination of parts.
If you used an Allison 6 speed your RPM's would be fine.
Get some EFIlive action going on or atleast one of those TPS amplifier devices so you don't have to mat the pedal to get 2500 RPM and it will be fine.
Or go to 35's. That would put you same gearing as a stock GM pickup with the duramax.
Duramax swap is way too messy to ever appeal to me, but I am carefully planning a healthy and clean 12 valve and 6 speed Allison swap into an 80. My tape measure says it will fit fine with the right combination of parts.
If you used an Allison 6 speed your RPM's would be fine.
- Thread starter
- #30
I guess I don’t understand what your saying? Have you put a duramax in a land cruiser? What do you mean by “messy”?
I’ve been driving my cruiser with the duramax for a couple weeks now and im not sure what you mean by “it will feel terrible”, lol like I’m seriously driving it daily and your telling me it’s going to feel terrible lol, come on now
I do agree after some efi live it’s going to have more power, but as it is now it’s a night and day difference then stock engine
Let me explain-
No, I have not installed a Duramax in an 80. I like Duramax, but the complexity of them, the plumbing and total opposite of KISS does not appeal to me whatsoever for a swap. A duramax is a great engine in a GM pickup. It is not an engine I will use to convert anything else. Too much mess to make it work. That's what I mean by messy. No offense intended whatsoever.
Duramax has an electronic throttle. In stock form any/all Duramaxes are turds. They do not have the throttle % VS fueling map to feel correct in a light vehicle at all.
You need to change the correlation between what your foot is doing and what the engine is doing. That will make a monstrous difference in your perception of the gearing of your Landcruiser. It's not that you need more power, it's that you need the first 1/2 of the pedal to actually do something so it doesn't feel like your matting the pedal to do 75 MPH.
Tune it, put some bigger injector nozzles in it. That will make a way more significant difference in driver comfort than going to a taller gearset.
I would highly recommend doing the transfercase gears though. That's a sound investment.
Can you post up a link for a Allison to toyota transfer case adapter? I didn't know there was one. Do you have a Allison in your land cruiser?
Stock axles should hold up fine unless it's a rock crawler.
I think your going the right direction
I think your going the right direction. I looked into going with a diesel swap and gearing was a big concern to me as well. I also don't like tall tires on a daily driver. I would look into the 3.54 gear Set. I have a feeling the tcase gears won't be enough.
I am telling you guys, I have over 200k on a Duramax with 4:10 gears and have had 35's and now 33's on it for the last 50k. It is just fine. I normally cruise at 70 mph 2300 rpms and it is fine, 20 mpg. it will do 90 or higher no problem as well. Mine is a LB7 and 5 speed Allison. The 4L80 is a 25% overdrive. Should be fine. I really think everyone is overthinking it. I would focus on fine tuning everything and enjoy it.
- Thread starter
- #36
I’m sitting right around 2500 going 75mph I’m just thinking
if I was <2k my mpg’s would be great and it would be less loud in the cab, I plan on taking this all around the country and sometimes pulling a camper
I tow a 27' enclosed trailer with than is 10' tall all over the country. I have 4" exhaust from the turbo back with a Quiet muffler on it. It is not loud inside of my truck. CCSB. Your muffler might be loud if it is a straight thru design. I love that it does not downshift much but my trailer weights in at 13k. The 3:54? gear set might be your best option if you are looking to lower the rpms that much. Might be cheaper to put some 35' s on it?? Either way good to see someone put a Duramax in an 80!
thatcabledude
GOLD Star
I like how you are asking about a HIGHER gear set and people are telling you to tune and do mods for more power. Lol
thatcabledude
GOLD Star
Lol why
2500 @ 75 is not bad gearing for a Duramax.
Also, the math says you are wrong. 4l80e od ratio is .75. That would give you 2348 RPM @ 75, not 2500. You would have to have a 31" tire to do 2500 @ 75.
With 10% od gears and 33" tires you'd be 2113 rpm @75 mph. That's very low for 75 mph.
It's also important to realize the taller your final drive ratio is the bigger the rpm drop between gears will be and the harder your torque converter will be working when it's unlocked.
And again, the tuning part is about driveability, not power. Anyone who doesn't get that should not be doing an engine swap.
Also, the math says you are wrong. 4l80e od ratio is .75. That would give you 2348 RPM @ 75, not 2500. You would have to have a 31" tire to do 2500 @ 75.
With 10% od gears and 33" tires you'd be 2113 rpm @75 mph. That's very low for 75 mph.
It's also important to realize the taller your final drive ratio is the bigger the rpm drop between gears will be and the harder your torque converter will be working when it's unlocked.
And again, the tuning part is about driveability, not power. Anyone who doesn't get that should not be doing an engine swap.
