3.90 gears...which brand?
01-03-2012, 09:15 PM
#1
4th Gear Member
Thread Starter
Join Date: Dec 2007
Location: Maryland
Posts: 1,503
3.90 gears...which brand?
Putting 3.90s in my '99 GT auto. Only brands I'm familiar with are Motive and Richmond. Motive costs $70 more so I'm assuming they're made better. Any other brands to consider and which would you prefer? Thx guys.
01-04-2012, 08:56 AM
#3
3rd Gear Member
Join Date: Mar 2009
Location: NOLA
Posts: 665
i was debating 3.90's too but heard that they whine and whatnot, and they aren't a gear made by Ford, so people inherently think they don't belong in a mustang. So i did some figuring out on what my expectations were with the stang and decided , 4.10's?? why the hell not!
only have 125mi on them so far, and they still whine, and they were installed by a certified ford tech at a dealership (friend of a friend, done as a side job) who works on rear ends for a living. i don't find the gear to be a pain at all thus far, and i've done almost only stop-and-go city driving since installed (of course having a 5 speed, its a bit different than ur situation). anyway, i say if you're gonna gear it up, go 4.10's. they're cheaper than 3.90's, at least. i would recommend getting the Ford Racing ones too, but some of the Ford Racing gears are made by Motive anyway. I went with Motive simply because mine were on some blowout sale, but since Ford apparently has contracted em out, you have a chance of getting Motive gears either way..
only have 125mi on them so far, and they still whine, and they were installed by a certified ford tech at a dealership (friend of a friend, done as a side job) who works on rear ends for a living. i don't find the gear to be a pain at all thus far, and i've done almost only stop-and-go city driving since installed (of course having a 5 speed, its a bit different than ur situation). anyway, i say if you're gonna gear it up, go 4.10's. they're cheaper than 3.90's, at least. i would recommend getting the Ford Racing ones too, but some of the Ford Racing gears are made by Motive anyway. I went with Motive simply because mine were on some blowout sale, but since Ford apparently has contracted em out, you have a chance of getting Motive gears either way..
Last edited by trailor; 01-04-2012 at 08:58 AM.
01-04-2012, 09:31 AM
#4
To debunk this myth once again. Ford racing does not make gears at all motive makes the gears for ford racing so they are simpy motive gears in a ford racing package. Motive offers 3.90s directly so dont be afraid to run them because if ford racing had them it would be the same parts just like 4.10s for example. Those ford racing gears are motive gears in a ford box.
01-04-2012, 10:09 AM
#5
4th Gear Member
Join Date: Jun 2010
Location: TEXAS
Posts: 1,452
Someone may have installed the 3.90s wrong a few years back and got gear whine so started to spread the word that the 3.90s whine and it may have just grown from something as simple as that. Someones bad experience. 3.55s, 3.73, , 3.90, 4.10 will all make noise if installed wrong.
01-04-2012, 11:36 AM
#6
4th Gear Member
Join Date: Sep 2009
Location: NC
Posts: 1,481
I am running MOTIVE 3.90(actually 3.91's) in my car and have no issues.
The quality of MOTIVE gears are just fine, so don't shy away from 3.90 because of that. In fact, I had to go with 3.90 since 4.10 would turn too many rpm in the 1/4, and 3.73 just didn't come out of the hole like the steeper gears.
I wouldn't let mpg sway me from 4.10 to 3.90, but with a manual trans the 4.10 just runs thru gears so quickly in town (leaving traffic lights, etc). IMHO, 3.90 are a real good compromise ratio for a DD car that gets some passes at the track.
GOOD LUCK!
The quality of MOTIVE gears are just fine, so don't shy away from 3.90 because of that. In fact, I had to go with 3.90 since 4.10 would turn too many rpm in the 1/4, and 3.73 just didn't come out of the hole like the steeper gears.
I wouldn't let mpg sway me from 4.10 to 3.90, but with a manual trans the 4.10 just runs thru gears so quickly in town (leaving traffic lights, etc). IMHO, 3.90 are a real good compromise ratio for a DD car that gets some passes at the track.
GOOD LUCK!
01-04-2012, 04:26 PM
#7
3rd Gear Member
Join Date: Mar 2009
Location: NOLA
Posts: 665
I am running MOTIVE 3.90(actually 3.91's) in my car and have no issues.
The quality of MOTIVE gears are just fine, so don't shy away from 3.90 because of that. In fact, I had to go with 3.90 since 4.10 would turn too many rpm in the 1/4, and 3.73 just didn't come out of the hole like the steeper gears.
I wouldn't let mpg sway me from 4.10 to 3.90, but with a manual trans the 4.10 just runs thru gears so quickly in town (leaving traffic lights, etc). IMHO, 3.90 are a real good compromise ratio for a DD car that gets some passes at the track.
GOOD LUCK!
The quality of MOTIVE gears are just fine, so don't shy away from 3.90 because of that. In fact, I had to go with 3.90 since 4.10 would turn too many rpm in the 1/4, and 3.73 just didn't come out of the hole like the steeper gears.
I wouldn't let mpg sway me from 4.10 to 3.90, but with a manual trans the 4.10 just runs thru gears so quickly in town (leaving traffic lights, etc). IMHO, 3.90 are a real good compromise ratio for a DD car that gets some passes at the track.
GOOD LUCK!
01-04-2012, 05:51 PM
#8
4th Gear Member
Thread Starter
Join Date: Dec 2007
Location: Maryland
Posts: 1,503
01-04-2012, 06:21 PM
#9
4th Gear Member
Thread Starter
Join Date: Dec 2007
Location: Maryland
Posts: 1,503
Thx guys for the input. Wasn't trying to start a one gear vs. another thread. I'm using a gear calculator that's really helpful. With 4.10s, 3rd gear will only reach 99 mph at 5500 rpm, while the 3.90 will get me to 104, closer to 12 sec. mph after some added power. I figure with the 3.90 I'll be faster than with 3.73s but a little better than 4.10s if I need to hit the highway.