I Need Your Help Differential Question
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I Need Your Help Differential Question
You have all been a great help to me that's why once again i asking this quesition. I have to have my whole differential redone on my 2001 Expedition 4.6L XLT 2WD. Now, i have all the parts except for the ring gear and pinion. the part number for it is 5L3Z4209A. It's 8.8 ring gear and 3:31 pinion ratio. My question is i saw the exact same thing on ebay but it came out of a 2005 Mustang, will this fit on my Expedition? The reason why i'm asking is because i can probably get it dirt cheap. I just have to be absolutely sure that it will fit because i live in the Philippines and i have to have my father bring it half way around the world.
How you all can help me on this. Thank you...
How you all can help me on this. Thank you...
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Thanks for the advice 04markIII, the guy who is selling the parts is a ford tech and the reason why he's selling them is because he changed his gear ratio. He says they're like new with no problems. Is it possible to put 3.55's instead of 3.31's? Ford philippines told me that is should be the same exact ratio as the original. How much are you selling it for?
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Since you have a 2wd you can put any ratio in you desire, 3:27 up to 4:30's and because your speedo is controlled by the PCM it can be reflashed for the new gears so that the speedo is correct. 3:31 is an odd ratio....for an 8.8. 3:27, 3:55, and 3:73 are very common though. I actually have a friend who has a set of 3:73's (this is what came in tow package Expys) that have about 7000miles on them and would take $75 for them.
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this is the ring gear & pinion
This is the ring gear and pinion that i'm looking at, i already bid on it so i hope that this is the right part.
8.8 ring gear and 3:31 pinion
8.8 ring gear and 3:31 pinion
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From: Cornelius, Oregon
the higher the ratio, the more the engine spins per revolution of the tires. So for example with the 3.73 gears, the driveshaft turns 3.73 full revolutions for each single revolution of the tires. On your 3.31 gears, the driveshaft only spins 3.31 revolutions.
The higher the ratio, the better it is for low-end work like towing. The lower the gear the easier it is to get heavy loads moving because of the greater mechanical advantage the engine has over the tires. But you're sacrificing top end. The engine will be running at higher RPMs when you're cruising down the freeway and costing you more gas. It's all a trade off and you need to figure out what you want your truck to do.
The higher the ratio, the better it is for low-end work like towing. The lower the gear the easier it is to get heavy loads moving because of the greater mechanical advantage the engine has over the tires. But you're sacrificing top end. The engine will be running at higher RPMs when you're cruising down the freeway and costing you more gas. It's all a trade off and you need to figure out what you want your truck to do.
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Thanks pitrow, well i live in the Philippines and my usual driving is maximum 45mph in the city and thats on a Sunday! LOL... I'm usually at 25mph in the city, a lot of traffic and narrow roads here. There aren't many highways to speak of here so i will be going slow most of the time. I only have 49,000kms on my truck, i have no idea why my rear end went out soo soon. i take care of her like a baby. Anyway, considering that i don't drive fast at all and i'm usually just within the city limits, should i go with a higher ratio? If i do, will it improve off the line power? I remember driving a 2000 stock expy and it seemd to have better off the line power than my "01. Could that be because of the gear ratio?
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From: Lunenburg, MA
Originally Posted by cccullen
I remember driving a 2000 stock expy and it seemd to have better off the line power than my "01. Could that be because of the gear ratio?
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If you don't tow I think the 3:55's would be perfect. You may not need the torque multiplication of 3:73's. Driving the way you speak of though, I doubt any gear is going to make much difference in mpg. With no highway driving a numerically higher gear should actually HELP your mileage a bit. It would hurt it if you drove 70mph for 30-40 miles a day. Make sure that all the races/bearing and seals get replaced too. Any entire 8.8 rebuild kit is only $120 from Summit.
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That's why i was so interested in them Adam. For $5 you can't go wrong.LOL. I am interested with the 3.55's or higher though. My Expy is real slow of the line, i even have a hard time on steep slopes starting from a dead stop.
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From: Lunenburg, MA
Originally Posted by cccullen
Adam, What's summit? $120? not bad at all, is that summitracing.com?