3.9 rear diff???????????????

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Gottolovem
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3.9 rear diff???????????????

Post by Gottolovem »

Ok I'm confused I have two rear carriers both were taken out of manual tranny cars by me personally.
On has it's stamp and is 4.1 has 41 ring gears and 10 pinion gears 41÷10=4.1

The other one has no stamp it has 43 ring gears and 11 pinion gears 43÷11=3.9

WTF I'm confused I know this came out of a manual car
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Petros
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Re: 3.9 rear diff???????????????

Post by Petros »

did it come out of a two wheel drive? the auto trans uses a 3.9 as I recall.
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Gottolovem
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Re: 3.9 rear diff???????????????

Post by Gottolovem »

Nope 2wd has no rear axle gears.I pulled it myself out of a manual 4wd car that drove all the way from Baja Mexico in 4th gear because it blew 5th.
We ended up replacing the entire gear set to 4.1 because I had no 3.7 replacement at the time.
I'm totally confused as to how this kid drove from Texas to southern Mexico across to the Baja Peninsula on a ferry and back to me with the wrong gears in the ass end of his car. In and out of 4wd all the while i would guess in Baja Mexico.
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dlb
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Re: 3.9 rear diff???????????????

Post by dlb »

i'm assuming you double checked your count of the gears but had to ask just in case.
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Gottolovem
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Re: 3.9 rear diff???????????????

Post by Gottolovem »

dlb wrote:i'm assuming you double checked your count of the gears but had to ask just in case.
Ohhh yea multiple time's
Even used two different calculators :oldgeek:
tercel4wdrules
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Re: 3.9 rear diff???????????????

Post by tercel4wdrules »

They used 3.9 in the automatics, but it seems they also used that ratio in the manuals in Japan as I recall seeing that final drive ratio in one of the Japanese magazine scans. Unless someone put one by mistake from an auto into that manual transmission car at some point in the past, that's also a possibility.
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Gottolovem
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Re: 3.9 rear diff???????????????

Post by Gottolovem »

tercel4wdrules wrote:They used 3.9 in the automatics, but it seems they also used that ratio in the manuals in Japan as I recall seeing that final drive ratio in one of the Japanese magazine scans. Unless someone put one by mistake from an auto into that manual transmission car at some point in the past, that's also a possibility.
Hmmmmmmm
Will need to go check the transaxle that was in the car
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Petros
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Re: 3.9 rear diff???????????????

Post by Petros »

if it was not right hand drive, my guess is that someone replaced the original axle with one from an auto trans car. If he never used the 4wd on paved surface he likely would be okay, the ratio differences is small (but it may have felt squirly).
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
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