Hi everyone,
I swapped my SC400 Diff because the ring gear cracked. The Diff I used was from a GS400. Now when i'm driving, I notice a difference in the MPH. When coasting around at about 10 MPH the cluster says i'm doing 20+. What can I do to fix this problem w/o changing the Diff again ? It drives fine, I just want to be sure of how many miles i'm going.

 

lol well no ****, you removed your 3.92 gear for a 3.26, which is a huge difference.

Look into something like the "speedohealer" on google.

Also how does it feel now with a tall *** gear? More sluggish or no? You will get better gas mileage though!

 

Yeah I only found out about the ratio's after the fact...
It was a last minute swap so I didn't have time to research it more. The driving experience isn't much different; it still feels stock-ish but it could be quicker.

 

planning on going with this diff as well, approx how much is labor to install?

 

I'm not sure how much it'll be in your area but they charged me $200.00

 

The gs400 diff is perfect for a 6 speed

 

i just installed 4.27 from a supra into my 98sc400, which was 3.266 stock
and my speedo is still on point per my in-dash navigation system... what year is your car? maybe lexus changed their speedometer to electronic for the later models... another guy installed diff gears and said his speedo is correct also per his navigation system

very interesting....

and yes i can't rem the name brand, but its a speedo correction device, motorcyles usually use them but they work on cars also..

call a performance shop and they can tell you exactly.. its 60-90 bucks...

 

Try the Dakota Digital SGI-5. It'S a speedometer signal correction module. It's about $79.95.

 

^^^^that's the ONE!

 

My SC400 is a 92...
Ill try that device you guys recommended & trouble shoot the problem with my mechanic.
Thanks for the help everyone.