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720 rear gears


nissan720

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are the stock rear gears in a 1984 nissan 2wd 3.70.if changing to a 4.11 will there be a notable difference.would it be worth the time and effort performing the swap?

 

Yes there will be a difference, it will start out quicker, you will have to shift sooner, and if you were used to 3000rpms on the hiway with 370 gears, they will raise up to 3500/4000rpms with 411 gears, so if you don't like listening to your engine revved up high, stick with the 370 gears.

Most folks on here would go from 411s to 370s on a 2wd, not the other way around, but if your hauling heavy loads around, the 411 gears will make it nicer to drive.

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are the stock rear gears in a 1984 nissan 2wd 3.70.if changing to a 4.11 will there be a notable difference.would it be worth the time and effort performing the swap?

 

Only the automatic 2wd had 3.70 gears. Five speeds were 3.545. Look on the engine tag on the passenger side inner fender just below the hood hinge. The differential ratio is stamped far bottom right   HF35 is 3.545, HF37 is 3.7, HF38 is 3.889 and HF41 is 4.11

 

Using the stock tire size of 195/75R14 and in 5th gear on the highway.

 

Gear ratio... 3.545........ 3.70......... 4.11

55MPH....... 2,088....... 2,179...... 2,421... RPMs

60MPH....... 2,278....... 2,378...... 2,641... RPMs

70MPH....... 2,658....... 2,774...... 3,081...RPMs

 

 

Difference... yes indeed. Slightly poorer mileage, traded for better performance. In all gears and at all speeds the engine will be revved higher than with the stock installed differential gears. Speedometer will read higher than you are actually going. The 3.545 diff will have a 17 tooth speedometer drive in the transmission. Going from 3.545 to 4.11 is a 15.9% change so 17 up to 20 tooth is a 17.6% is as close as you will get. That's less that 1 MPH out at 50MPH. If you find a 4.11 in a truck grab the speedometer gear as well to go with it.

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listening to your engine revved up high

 

Music to my old failing ears.......

 

Mike, I think my 4.6 gears will put me almost at 3500 @ 70. Not run the numbers yet, 225x60-15 tires.

Will an L16 (yeah, it really is, I would not lie - too much) with 11:1 compression, 290 cam, 40mm smooth bore bike carbs pull 7k & 140 on the freeway?

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Well it's not like a day and a half job and $250 to do this. You can easily unbolt the axles and pull them out enough to disengage the diff without removing the hydraulic brake lines, drop the bum out and pop the other in. They don't make the gasket anymore so get a good quality sealer like Permatex Blue (not the fucking blue RTV shit the chevy owners like to trowel on their intakes) You should be able to do this in  a few hours.

 

It will probably be an automatic. And the speedometer gears from it won't work in a standard.

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I highly recommend it if you don't do a lot of highway driving. I switched from 3.7 to 4.11 and its my favorite easy upgrade I've done. Its screaming in 5th when you get up around 80, but it'll still cruise 60 nicely. It just gets a bit uncomfortable at times, but the loudness of my exhaust and height of my truck really don't help that either haha

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You don't want or need the whole thing (for that you should get the entire truck) so tell them you'll remove the third member yourself and offer them $50 and leave your number. Get a name. If they don't call call back in a week call back and ask for J. Doe.... and offer him $40.

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$100 is an ok price. Didn't want to suggest anything over $50 because  they were dicks for saying $300.

 

Are you getting the ratio you want? Checked the engine tag? The ratio is also stamped on the outside edge of the crown gear. Example 35:8 is 35 divide by 8 = 4.375 

 

37:8=4.625

37:9=4.11

35:9=3.889

37:10=3.7

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