Motive vs. Richmond vs. Yukon for 4.10's

[acammer]

Well, I'm in the market for some gears. I bought a used differential last summer with Richmond 4.10's in it. It came out of a stick turbo car, but I was told it had never seen the track or anything more than street tires. Who knows - the price was fair, and it was awesome in my bolt on LS3 car.

Fast forward almost exactly a year, and I now have a little more power, and a little more tire under the car, and the gears are toast - I've got a nasty bang/cluck/rough spot once a tire revolution under load, it's silent coasting - pretty sure that's a tooth on the ring gear gnarled up, and it's gonna eat itself in short order. I had actually swapped on my street tires for a few easy laps at Watkins Glen, and was driving home, stood on it hard in second, and it blew the tires off. Traction control caught it, snapped the power off, and then back on, and I'm pretty sure that's when it got hurt. Got progressively noisier on the next 50 miles driving home.

I'm definitely staying 4.10s - I'd go more gear if they had an option. The question is who's do I go with? I've read Richmond's thread about the 4.10 vs. revised 4.11, and I've read where people have still broken those. I don't think as many guys are running Motive or Yukon - but I've not read about anybody breaking them. I'd love to hear input on any experience you guys have had, especially on Yukon's or Motive's.

[Bo White]

Ive got 18k miles on my Motives

[Bo White]

I wish the 4.33s were still available.

[jdpeezy91]

Planning on going with the GM 3.91s asap in my bolt on M6 car how do you like the 4.10s? Still decent on the highway and top speed first still usable at all lol

[acammer]

Originally Posted by jdpeezy91

Planning on going with the GM 3.91s asap in my bolt on M6 car how do you like the 4.10s? Still decent on the highway and top speed first still usable at all lol

Yea, 4.10's are the right choice for an M6 car IMO, especially if you've got an aggressive cam. ~2000rpm in 6th at 70mph, which is just fine. First is definitely still use-able - pulls to 48mph @ 7200rpm with a 28" tire, which isn't really that aggressive IMO. Top speed would be 174mph@7200rpm in 5th, if you're brave enough.

[Bo White]

Mine is a daily and its th400 swap.

[jdpeezy91]

Originally Posted by acammer

Yea, 4.10's are the right choice for an M6 car IMO, especially if you've got an aggressive cam. ~2000rpm in 6th at 70mph, which is just fine. First is definitely still use-able - pulls to 48mph @ 7200rpm with a 28" tire, which isn't really that aggressive IMO. Top speed would be 174mph@7200rpm in 5th, if you're brave enough.

Seen 167 so far with stock gears was at about 5600 in 5th, just wondering what traction issues with 4.10s would be got a set of bias ply slicks for the track now but there's no launching on street tires as is just spins. Cams not to crazy tick "stage 2" 229/244 lift
.620/.611 separation could use lower gears for sure tho im hoping the 3.91 will be low enough to give me some more torque and still be good for highway cruising

[acammer]

Originally Posted by jdpeezy91

Seen 167 so far with stock gears was at about 5600 in 5th, just wondering what traction issues with 4.10s would be got a set of bias ply slicks for the track now but there's no launching on street tires as is just spins. Cams not to crazy tick "stage 2" 229/244 lift
.620/.611 separation could use lower gears for sure tho im hoping the 3.91 will be low enough to give me some more torque and still be good for highway cruising

3.91's are a nice improvement over 3.45's, but 4.10's are definitely better still. If you're a quarter mile guy then you would work backwards from trap speed. With my setup I expect to trap ~122mph. I make peak power at 6700rpm, so I'd like to be at or past that when I come through the traps. With a 28" tire and 4.10 I'm turning around 6050rpm through the traps - not totally optimal, but it's the best option I have. A 3.91 would trap at 5750, about 300rpm lower.

Going to a 26" tire would put me at 6475rpm which would be pretty nice, and a 4.56 with a 28" tire would be 6700 - perfect. Too bad they don't make that for our rear.

[jdpeezy91]

I do drag race the car been shooting for mid to low 11s which shouldnt be to hard being as i got 475 rwhp, most bolts ons besides intake TB or supercharger running on streets im usualy at 12.9s leaving at an idle and gradually getting after it basicly so i dont roll the tires off, my slicks are 26s atm and hook really well so far doing street testing can launch at 5k they make about one full turn and hook at 3k they dead hook havent had them to the track to make any passes yet so no times so far but i also want to get into doing some circuit tracks as there is a great one local and i love taking the car out for some "spirited" road trips out on the interstates so i really dont wanna loss to much driveability just to get a little lower quarter mile time im worried 4.11s would make my gears to short for the circuit track or playing out on the highway

[jdpeezy91]

Acammer after reading some of your posts im kinda thinking about the 4.11s now but with all the bad reputation they have ill probley end up pulling the trigger on the 3.91s