FJ40, J30 3-Speed 3rd Gear Grind? (1 Viewer)

Ackcruisers

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I’m running 33x10.5R15’s. With passenger side rear wheel off ground, 1 wheel rotation, prop shaft rotated approx 2.1 times. Two rotations = 4.3 times. There are numbers on diff showing 41111-6001.
View attachment 2371545
@brian @Dizzy ....are you sure one rotation of the wheel turns the drive shaft either 3.7 or 4.11 times? One rotation equaled 2.1 times on mine. Twice equaled 4.3.
 

Ackcruisers

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Did you replace the O ring on the idler gear or just use silicone?
Yes, the rubber O ring was replaced by me after easing out idler and picking it off. The installed O ring was in perfect shape. It appears the casing is worn causing leaks and with my easing out shaft, I created small leak on the front side expansion plug OEM# 90339-27010.
Here are images of my transfer case out of truck when truck was assembled.

8082EFF9-F43B-44D9-B605-2238721F40D4.jpeg


57994332-F95B-46B2-B208-4279E4484CB1.jpeg

4EE7613E-7C7A-4DD6-91D7-B5BAB66C4814.jpeg

I would prefer to use this transfer case vs. buying new one.
 

brian

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It will take the drive shaft...pinion gear...either nearly 3 and 3/4 revolutions or just over 4 revs to get the ring gear...the tires to make one revolution.
 

Ackcruisers

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It will take the drive shaft...pinion gear...either nearly 3 and 3/4 revolutions or just over 4 revs to get the ring gear...the tires to make one revolution.
If that’s the case then what gear ratio do I have when just over 2 revs of the drive shaft /pinion gear move the tire one complete revolution?
 

Living in the Past

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It's a crappy video but still.

When one tire is solid on the ground and that side can not spin it cause the pinion to spin twice as fast. Easy way is on flat ground with wheels pointed straight to roll the tire one turn and count how many times the driveshaft spins. Putting a mark on the tire and driveshaft will make it easier to do. Just under four revolutions of the driveshaft probably 3.70s. Just over four probably 4.11s. Aftermarket could be different.
 

Ackcruisers

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When one tire is solid on the ground and that side can not spin it cause the pinion to spin twice as fast. Easy way is on flat ground with wheels pointed straight to roll the tire one turn and count how many times the driveshaft spins. Putting a mark on the tire and driveshaft will make it easier to do. Just under four revolutions of the driveshaft probably 3.70s. Just over four probably 4.11s. Aftermarket could be different.
Thanks for the explanation. I now understand. My truck was jacked up on rear wheel passenger side and driver side rear was on ground. Based on this, two times around should be the same as both tires off ground. I believe my rear diff is a 4.11:1.
 

Living in the Past

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Thanks for the explanation. I now understand. My truck was jacked up on rear wheel passenger side and driver side rear was on ground. Based on this, two times around should be the same as both tires off ground. I believe my rear diff is a 4.11:1.

Toyota was concerned about average gas mileage of their vehicles across the entire line in the US. Only reason for the 3.70:1 was to help with the mileage. In a petrol 4X series 3.70:1 would be hard to find in any other market. Diesels on the other hand seen those in other markets in 60 series. 4.11:1 was pretty standard on most 4X series. From the mid sixties on.
 

Dizzy

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The propeller shafts will need to be swapped for the length change on the gear boxes. I wonder if the non-USA used the older 3-speed flange patterns? It might need new pinion flanges to go with the swap as well, or if you can adjust the length at a cheaper price?
 

brian

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Toyota was concerned about average gas mileage of their vehicles across the entire line in the US. Only reason for the 3.70:1 was to help with the mileage. In a petrol 4X series 3.70:1 would be hard to find in any other market. Diesels on the other hand seen those in other markets in 60 series. 4.11:1 was pretty standard on most 4X series. From the mid sixties on.
3:70s are awesome, i replaced my 4:11s with them and have zero regerts.
 

Living in the Past

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3:70s are awesome, i replaced my 4:11s with them and have zero regerts.

Toyota really didn't build with with speed in mind. Dirt roads around the world in the sixties and seventies 4.11:1 were probably the best gearing. Spring of 1994 I installed a H42 into my 68 that probably had 29" tires at the time. Fall that year a friend of mine bought a 79. I remember going to test drive it with him. I wasn't sure I was in low range or not. It had 31X10.50X15" tires, 1.99:1 low range and 3.70:1 diff gears. Could easily tell the difference between my 68. He kept for a few years until 1997 when he got tired of it. At that time he gave me a good deal and added to my collection. Plan is to install the H55F with lower first gear before pulling the 3.70:1 gears. I have a 82 FJ40 rear axle for hand brakes and it has 3.70:1 as well. Believe our transfer case (8/80+ split transfer case) have slightly lower range with the H42/3.70:. Figure with a H55F lower first gear and slightly lower range would be okay off road. First gear friendlier on pavement and lower RPM on the highway.
 

brian

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but the torque is more than enough to handle them just fine.
with a non usa carb, jetted with no regard for economy, a 3f dizzy with pertronix and 33x10.50s with an h42...driving it like the company puts gas in it, im seeing 15-16 mpgs.
 

Ackcruisers

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Since this is an import I’d check the front diff as well to make sure it’s 4:11.
Good point, will check that today. Just drained the 3 speed gear oil to inspect. Attached is image of plug which appears to have a lot of metal on it for a transmission that was rebuilt with less than 500 miles on it? Or, is this to be expected?
C6C34C76-6DBA-4435-983B-90572FCA9AA3.jpeg
 

65swb45

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Considering your thread title has the word grinding in it, not surprising.

Regarding the coarse nature of the 3speed, and the propensity for missed/hard shifts, an old friend adopted the attitude of calling out regularly


’Grind me a pound, butcherman.’
 
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You've got a 3 speed gearbox and hopefully the 3 speed bell housing but you've got the later preasure plate clutch and hopefully again, the later flywheel.
With such a mish mash of bits there, I'd be looking at what the thrust bearing and slave cylinder are doing...

Gaz..
 

Ackcruisers

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You've got a 3 speed gearbox and hopefully the 3 speed bell housing but you've got the later preasure plate clutch and hopefully again, the later flywheel.
With such a mish mash of bits there, I'd be looking at what the thrust bearing and slave cylinder are doing...

Gaz..
The bell housing is for a 3-speed.Yes, flywheel is #13451-60060 for 4 speed. Here is a look with cover off. Bearing spins and looks new.
EB2EF423-DB9B-4A98-9395-08E3940FDB9F.jpeg
 

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