98Gs4001UZ

Hey guys just got my Gs300 rear and it ready to be installed in my gs400. I'm pretty excited I've been waiting for this for weeks. Is there anything I need to know about the install before I start? I hear it just bolts in but it's usually not that easy. I'll post updates as soon as I complete the install.

TLcoats

iTrader: (11)

Yeah it's a pretty difficult install if you don't have power tools. I had my mechanic due it because i had trouble getting the bolts un torqued. Just make sure to use some loctite just in case. But the 3.92 gears work perfect for this car. I love the new gear ratio!

98Gs4001UZ

Yeah I'm a dodge diesel tech I got plenty of power tools and access to lift so that should make things easier. Thanks for the info.

TLcoats

iTrader: (11)

Yeah your good to go then! Enjoy the new gears man, they make a great difference! Oh and you have to unbolt the middle section of the exhaust for the diff to drop down. It's pretty obvious but just wanted to let you know.

98Gs4001UZ

Awesome thanks. What about the where the axle shafts bolt to the diff are those the same? Or do I have to swap them for one diff to the other? Same with where the drive shaft bolts to the diff?

speedaddic

iTrader: (10)

Pretty straight forward install. I did it without power tools, just a big breaker bar.

TLcoats

iTrader: (11)

Everything is the same. Simply swap and play.

98Gs4001UZ

Awesome that's alot. That makes everything easy now. I should have it in by lunch time today.

benbuilt4u

iTrader: (5)

took me 45 minutes to do mine at work. just remember you need a 12mm allen wrench.

98Gs4001UZ

Ok the rear diff is finally installed after 1h and 18m!! It runs great! Such an inexpensive upgrade (well if you do it
Yourself) and the difference is very noticeable. Thank you guys again for the advice before I started this project.

TLcoats

iTrader: (11)

Wow! My mechanic charged me 3 hours... Enjoy the upgrade!!

100bajan

iTrader: (12)

I am a real novice and I am hopefully getting a GS this week, I want the 400 so my question is what advantage do I get from using a 300 rear differential?

TLcoats

iTrader: (11)

The stock GS400 gear ratio is 3.23. The stock GS300 gear ratio is 3.92. So basically you get a higher gear ratio so your rpm's are higher at any given speed increasing low end speed and torque. It also helps city driveability since your always in the torque curve. But you do lose some MPG's on the freeway since your revving at about 3k at 80MPH

98Gs4001UZ

Wow he made his money for sure :/ . Yeah I very much in enjoy it.

98Gs4001UZ

Yup was doing 80 and it was about 3k. Which really isn't that far off from what I was running before. 50 mph I was at 2k and now I'm at 2200 not that
Bad of a difference, but as for as torque and power you can definitely feel the difference