Eaton lockers?

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80t0ylc said:
I also run 35's and originally, I would have put 4.88's in because I read somewhere, possibly in this forum, that that was the best setup. However, Zuk suggested 5.29's because he had gotten enough feedback from his customers that they wished they would have gone with 5.29's. I pull a trailer when overlanding and it works great, except for the long highway passes. The only other down side is when I do 80 on 80 in my 80, it really pulls the revs :hmm: That's an inside joke for those that live near I-80. (80 mph, on I-80, in my 80 series). But seriously, after running 33's and upgrading to 35's with stock gears for a while, when I was done with the lockers and new gears, I got the pep back in my 80! And off road, it was even better. :bounce:

I'm OK with 70-75 mph on the highway:
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What kida of weight are you towing? About how much do you weight. Seems 5:29's might be a bit much, fuel economy may suffer, but it is an 80, so anything over 10 mpg is ok, I guess! I do not drive much over 70 mph so it may not matter.
 
CharlieS said:
Would the Sumo high range transfer gear be a good pairing with the 5.29:1 diff gears?
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I wouldn't do the high range gears with 5.29s. The high range gears give you a 10% increase over the stock gears, that will give you a ratio of 5.8 which would be too much especially for daily driving in my opinion. Great for crawling.
 
OffRoadScott said:
I wouldn't do the high range gears with 5.29s. The high range gears give you a 10% increase over the stock gears, that will give you a ratio of 5.8 which would be too much especially for daily driving in my opinion. Great for crawling.
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Thank you. I totally misunderstood, I thought it would lower rpms in high gear, which would help the high revs the previous poster mentioned. I must have it backwards.

I have the sumo low gear for offroad...
 
CharlieS said:
Thank you. I totally misunderstood, I thought it would lower rpms in high gear, which would help the high revs the previous poster mentioned. I must have it backwards.

I have the sumo low gear for offroad...
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They actually have one that will do that...

Sumo Gear High Range Gears 4.10 - 3.70

Sumo Gear High Range Gears 4.10 - 4.56

If you are looking to do gears and the transfer case I would do 4.56 that would put you right around 5.0 in the thirds essentially.

I did 4.88 as I do plan on going 37s and maybe 40s in the future.
 
These are my RPMs with 4.88s running 295x75x16 Nittos with Lutz speedometer calibrator. No speed demon but boy does it feel better than when I was running stock gears with these heavy tires. My thought is if I go 315 or bigger I can adjust at the transfer case.
IMG_1529.webp


Zero regrets with the Eaton and wiring setup

IMG_1530.webp
 
CharlieS said:
Would the Sumo high range transfer gear be a good pairing with the 5.29:1 diff gears?
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Maybe, but 10% is pretty negligible, about a 200 rpm change. Wouldn’t be worth the cost imho.
 
As they say in the midwest, "eaton aint cheaten"

I had my Over / Under t-case gears installed by George at Valley Hybrid, Valley Hybrids will do T-Case rebuild shipping exchanges or sell you the parts, Timmy The Tool Man and George have an excellent T-Case rebuild series on youtube. My plan is to perform the diff locker install one at a time without having to re-gear both diffs and front axle rebuild simultaneously, minimizing down time and upfront $$$. Plus this way I keep the full strength of the stock 4:10 gear ratio. Hopefully I wont have to buy new diff gears when lockers are eventually installed. I will have lower T-Case crawler gear and part time T-case along with the underdrive. I believe locker install for existing gears will be cheaper labor cost as well. .
 
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JoeCova said:
Maybe, but 10% is pretty negligible, about a 200 rpm change. Wouldn’t be worth the cost imho.
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I run 5.29 and the 10* under drive sumo gears it was a must with 39s big difference. and unlike the low range gears they work in High and Low range.
 
Broski said:
I run 5.29 and the 10* under drive sumo gears it was a must with 39s big difference. and unlike the low range gears they work in High and Low range.
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It's still only 200 rpm but if I was running 39's I would want everything I could get as well.

The only thing we can really do is swap transmissions, first gear isn't low enough and 3 speed + OD is super lame.
 
JoeCova said:
It's still only 200 rpm but if I was running 39's I would want everything I could get as well.

The only thing we can really do is swap transmissions, first gear isn't low enough and 3 speed + OD is super lame.
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All I can say is 200 RPMs made a big difference in drivability both on and off road.
 
Broski said:
All I can say is 200 RPMs made a big difference in drivability both on and off road.
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Always interesting how butt dynos work. 10% was big for you and I can barely detect a difference on 16%. I think we can agree though its better to go lower.
 
JoeCova said:
Always interesting how butt dynos work. 10% was big for you and I can barely detect a difference on 16%. I think we can agree though its better to go lower.
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Ok I will explain
I have been wheeling my 80 for 8+ years and that’s all I do with it.
I run the hardest west coast trails, Johnson, Valley, Moab, and Sandhollow to name a few I’ve been through a lot of the trail many times.
I started on 35s then 37s and now 39s
It’s street legal and insured. I always trailer it to the places I going. But sometimes the staging area is a few miles away from the trailhead.
The first thing I noticed when I went to 39s when I was aired down and trying to drive on the street a few miles to get back to my trailer. It was hard to get the car up to speed. I never had that issue with 37 also when approaching an obstacle it was hard to get the front tires to pull up. I also never had that issues with 37s.
After installing the 10% underdrive it felt like I was on 37 again no issue driving on the street air down and popping up obstacles just like I was on 37s
Also, with 5.29s 10% underdrive final gears the speedometer is spot on with 39s
It’s possible you don’t have as much time as I do in the seat of an 80.
My butt Dino is telling me there’s a big difference even though it’s only 10% or 200 RPMs😎
Cheers
 
Broski said:
Ok I will explain
I have been wheeling my 80 for 8+ years and that’s all I do with it.
I run the hardest west coast trails, Johnson, Valley, Moab, and Sandhollow to name a few I’ve been through a lot of the trail many times.
I started on 35s then 37s and now 39s
It’s street legal and insured. I always trailer it to the places I going. But sometimes the staging area is a few miles away from the trailhead.
The first thing I noticed when I went to 39s when I was aired down and trying to drive on the street a few miles to get back to my trailer. It was hard to get the car up to speed. I never had that issue with 37 also when approaching an obstacle it was hard to get the front tires to pull up. I also never had that issues with 37s.
After installing the 10% underdrive it felt like I was on 37 again no issue driving on the street air down and popping up obstacles just like I was on 37s
Also, with 5.29s 10% underdrive final gears the speedometer is spot on with 39s
It’s possible you don’t have as much time as I do in the seat of an 80.
My butt Dino is telling me there’s a big difference even though it’s only 10% or 200 RPMs😎
Cheers
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Ya, I def don't have experience with 39s on an 80 but I wheel the same trails on 35's. Like you, this 80 is just for wheeling and camping. While I'll tow the cruiser to the Rubicon I generally just drive it form Colorado to Moab and it struggles in all of the same ways it did with 4.10 with the exception of low speed descents on the the trail.

Glad it made the difference for you with 39s
 
matzell said:
What kida of weight are you towing? About how much do you weight. Seems 5:29's might be a bit much, fuel economy may suffer, but it is an 80, so anything over 10 mpg is ok, I guess! I do not drive much over 70 mph so it may not matter.
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The link to my trailer is in my sig. Three Feathers 'Trail Head' off road trailer Edit: Approx 1400 lbs wet - before gear is loaded. (post# 24 in thread) The 80 is around 7200 lbs. Yeah, it's a bit much, but has a fair amount of armor and is set up for overlanding. Link for list of mods is also in my sig '94 FZJ80 / list of mods
 
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