Pontiac G8 Forum banner

3.45 gears installed..pics to come...

23K views 52 replies 22 participants last post by  TexasXD1  
#1 · (Edited)
hey guys,

Just wanted to share my install experience and my thoughts about the 3.45's installed a couple days ago. I had recently purchased a comlete diff assembly locally out of a wrecked 2013 SS camaro.

The install went very well, no hiccups whatsoever. This was truly a 100% bolt in installation. took about 2 hours doing it by myself on the garage floor. I should say i am a mechanic by trade, but have never performed this swap before.

My first initial reaction to the first test drive was, "wow, the car feels about 800 lbs lighter" first gear and second gear pull pretty hard and i was able to get a 3rd gear chirp in the morning. haha. It feels like these are the gears that should of come with the car in the first place.

My upgrades already include: vararam intake, shorty headers, full exhaust, dyno tune. Stock torque converter. My tires are a 275/30r20 all the way around.

My cruising rpms with the 2.92 gears were roughly 2000 rpms at about 80 mph. That has increased to roughly 2340 rpm at 80 mph. Used my GPS to get the "after" speedo reading.

I will be getting the TCM tweaked tomorrow morning and will update you guys and have some pics too.

Have a great day.
 
#2 ·
Dang, I want this swap!

Glad to hear the good results!
 
#4 ·
i found mine locally for $400. It looks like people are asking online for around $500-$600. Don't know if there selling for that much. My advice would be to check out your local craigslists for totalled/wrecked camaros and/or if you have a local company that specializes in selling used parts. Our company here in vegas is LKQ. A professional outfit that sells used/new parts to the public/dealerships/etc.
 
#5 ·
just got back from the tuner and had the TCM tweaked and speedo corrected. Going to the track tonight to test them out. Heres some pics from the install.

Image


Image


Image


Image
 
#8 ·
hey guys, sorry for keeping you waiting. Track day was hot and humid. 98 degrees and raining in the surrounding areas. what i can confidentally tell you is my overall ET's dropped .2-.3 seconds. Last year, i was consistently in the 14.1-14.2 area. My best run the other night was 13.88 @ 101 mph with a 2.12 second 60 foot time. I was running my street tires. 275/30r20 continentl contitrac. Overall im very happy with it and the car definately has that "feel it in your seat" feel off the line.
 
#10 ·
They were very easy to remove. Remove the axle nut, disconnect a couple of the lower control/trailing arms, disconnect the wheel speed sensor connectors. I used my hammer and a drift to then drive the half shafts out of the splined hole of the knuckle and then removed the shafts from the knuckle by pulling and folding the knuckle out of the way. Then removed the shafts from the diff center section. These came out surprising easy. I simply used a 12" pry bar, wedged it between the half shaft and the housing and popped it out. Most halfshafts I removed can be temperamental because of the c-clip retainer, but these slid right out.
 
#11 ·
Did you put new bushings in the diff before reinstalling.
 
#12 ·
I did not for a couple reasons. First the diff bushings were in excellent shape since the unit I installed was extremely low mileage. Second, I wasnt sure if I was going to be happy with the gears. I didn't want to invest more money into something if I wasn't sure about it :)
 
#14 ·
I personally think 3.90 would be to much gear. My rpms are already around 2450 at 80 mph and 70-80 is were I do most of my driving.
 
#15 ·
The 3.45s made my car really fun off the line and decent on the freeway. My city mileage had stayed pretty much the same when u gad the 2.91s, however my freeway mileage dropped 1.5-2 mpg. Took it to prescott az recently and I averaged 21 mpg.
 
#20 ·
Any 5th gen SS manual will have 3.45's with an LSD in it. The auto SS's and manual v6's have 3.27's with an LSD in them. The only one to avoids are the auto V6's and the ZL1 diff.

http://www.car-part.com/ is a good place to hunt for one along with the suggestions fleetman made.
 
#17 ·
2010-2015 should be all the same differential assembly. Any one of those should bolt into the g8 :)
 
#19 ·
i started reading this, then i saw you lived in vegas. then i realized i know who you are. i still haven't put in my 3.27's since i decided to do a lot more stuff when it cools off :gr_devil:
 
#29 ·
oh dang, lol. whats up thomas?! i havent been on here for almost a month. still loving my 3.45's let me know when your ready to install your 3.27's. ill be more than happy to give you a hand.
 
#22 ·
Just preference if my car was n/a close to stock power I would have 3.45 or more. My car is procharged once the gears are in the car should be low 800 rwhp I believe the 3.27 will help me get a more consistent 60'. The 2.92 always felt like it made it so hard to get out to 60'. My best 60 was a 1.82.
 
#28 ·
Stiffer poly bushings and the incorrect gear oil or lack of limited slip modifier can also cause noise.
 
#30 ·
It's at the bottom of my parts pile lol. Soon when it's less that 129493992 degrees outside it's among all the stuff getting finished up on my car
 
#31 ·
When you did the rear diff swap, did you reuse the (3) driveshaft coupling to diff flange bolts? Or did you replace them? Also, what fluids did you end up using and how much each? I plan to do this swap this weekend. Thanks.
 
#32 ·
When I changed mine, I reused the driveshaft bolts. Before I did the replacement, I searched around on here and other forums and did not see anyone metion replacing them. I made the assumption they were OK to reuse. If you take off the axle nuts (which I did not do when I swapped my differential) GM recommends that they be replaced and torqued properly. I know alot of people who take them off during the swap re-use them with no issues.

I used a quart of 75W-90 Royal Purple max gear oil. It does not require the addition of friction modifier. I went this route because I found alot of conflicting information about the proper fluids, and friction modifier as well as quantities. I went with RP so I didn't have to worry about adding anything.

Also note TSB PI0137C specifies updated axle seals that are less prone to leaking with the updated synthetic gear oil. The seals are GM P/N 22798805. They are easy to replace and IMO it is worth replacing to ensure you have the proper seals to avoid having to tear it apart because of a leak down the road