This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.
4.10 was never an available gear ratio in the US AFAIK. They were all 4.11 from 1991 through 1997.
- Thread starter
- #4
My 95FZJ80 is 4.10. I know cause I counted the teeth.
my 91 fj80 had also 4.10 it had stamp on the gear
hoser
SILVER Star
- Joined
- Jul 20, 2004
- Threads
- 274
- Messages
- 23,233
- Location
- Chandler, AZ
- Website
- www.tontorecreationalliance.org
This.
Not misnomer, simple math. The diff was redesigned for the 80 series, the early rigs are 4.1111111 the 80 and newer are 4.10.
inkpot
SILVER Star
Well, there's SO much difference between the two ratios that you could NOT possibly run them both on the same rig!! 
Cruiserdrew
On the way there
Well, there's SO much difference between the two ratios that you could NOT possibly run them both on the same rig!!
@inkpot I assume this is in jest because you can, as you know. I am running my old 80 4.10 rear gears in the rear of my FJ40, with 4.11s up front. Works fine. I read, but don't know, that some Chevy's came slightly mismatched from the factory.
Agree with @Tools R Us - The rear diff was fundamentally redesigned with the onset of the 80 series, and the ring and pinion changed from 37/9 to 41/10. And the change took place with the end of FJ62 production. I've counted in my FJ62 and it is indeed 37/9.
Looking at the 80 rear diff housing-the re-design significantly enlarged the oil passages, and the oil capacity seems higher as well Both beneficial changes. The older design has more stiffening "webbing", but the newer design looks like the entire differential is more triangular and stronger. The bearings also changed in the 80 differential as well though that reason is less clear to me. Maybe to standardize with other trucks in the toyota line up?
Thought the difference was open diff(4.11) vs locked diffs(4.10).
I have an early model with 4.11s and one locking 3rd from a an early model front axle which I believe is 4.10.
Was considering if I could put it in my rear and keep my front open?
I have an early model with 4.11s and one locking 3rd from a an early model front axle which I believe is 4.10.
Was considering if I could put it in my rear and keep my front open?
inkpot
SILVER Star
Yup! Being a bit sarcastic. Yes, some of the old domestic rigs had slight mismatch between front and rear axles.
AFAIK, the non locked units are totally interchangeable.
. : 1033"]Yup! Being a bit sarcastic. Yes, some of the old domestic rigs had slight mismatch between front and ear axles.
AFAIK, the non locked units are totally interchangeable.[/QUOTE]
Aren't you supposed to run different sized tires on those with different ratios! That way the ROLLING ratio is the same!
Yes, my 60 and 69 Chevy 4x4's had different ratios F/R. 3.92 front, 3.90 rear. It made the rear end pass the front in the mud. 69 was 4.11 front and 4.10 rear.
AFAIK, the non locked units are totally interchangeable.[/QUOTE]
Aren't you supposed to run different sized tires on those with different ratios! That way the ROLLING ratio is the same!
Yes, my 60 and 69 Chevy 4x4's had different ratios F/R. 3.92 front, 3.90 rear. It made the rear end pass the front in the mud. 69 was 4.11 front and 4.10 rear.
Cruiserdrew
On the way there
Well, 4.11 vs 4.10 is 0.25% different. It won't make any difference in the real world.
Why would they do this? What is the benefit?
Cruiserdrew
On the way there
Likely just what gears were available for what axle. Close is good enough.
I'm running one that is slightly different, and it is a non-issue.
I'm running one that is slightly different, and it is a non-issue.
My old Chevy was 4.10 / 4.11 and so is my f350. That slight difference amounts to exactly nothing in the real world. And less than nothing on part time vehicles.
Fair enough.
the difference between un-locked and locked diffs is in the diff carrier, not the C&P gearsets
It has more to do with the geometry of gear design and what will fit in the low pinion applications for those trucks. Since both front and rear are low pinion and they point opposite directions for different rotation, it is necessary due to how they must lay out for pinion to ring design.
The Toyota is high pinion front and low pinion rear, allowing them to essentially be the same setup and the same geometry, thus the same ratio.
And we sit here and debate tire size differences, when the trucks of old, that did NOT have VC's and all had locking hubs, have been around for LOTS of years. Many were very heavy duty, but they were also just plain HEAVY. My 60 K10 half-ton 4x4 pickup was 6600 LB with a 235 inline 6 cylinder. It was a workhorse at 35 MPH and lower. 55 MPH was TOP speed.
My son's current project is a 1970 GMC K2500 4x4. I think it is pushing 7000 LB. Dana 60 rear, and 44 in front. 350 w/ 4 speed. Doesn't flex worth a hoot, but will dig in the mud and pull anything it can get hold of. Also rides like a lumber wagon.
