Rear noises in the 2000 Trans Am, replaced gear oil, axle shafts, wheel bearings and parking brake shoes

After getting the suspension sorted with the new Borla exhaust system, I went on a quick drive and found the rear axle was noisy, like marbles rolling inside a tin and the rear axle was wining louder the faster I drove.

When I put the car back up on stands and started testing things, I noticed a lot of noise on the drivers rear side of the axle. It really sounded like bearing noise, so I decided to replace the axle shafts and bearings to be on the safe side. The previous owner replaced the pinion bearing about 3 years before I owned it and there were no leaks. I assumed there should not be any other issues with the diff. Once I had the cover off, the oil was pretty much trash, though I didn’t find any major chucks or anything just typical gear wear and the gears looked evenly worn. I went ahead and replaced the axle shafts and bearings and added new seals, in the process I found the drivers side parking brake shoe was loose, you could easily grab it and shake it around. The lightbulb went off at this point, that the issue may not have been with the diff but with the parking brake. I got new shoes and brackets to hold them in and this time the new shoes were snugly installed. I refilled the diff with heavier oil and also added GM posi additive, even though some folks say not to add it for this style of rear axle, a Torsen, there was a service bulletin from GM in the 2000’s that recommended adding the posi fluid to fix noise issues, so I did it. I figure it cannot hurt.

2000 Trans Am rear diff, cover soon to come off
2000 Trans Am rear diff inspection
2000 Trans Am rear diff inspection
Old bearings and axle seal on 2000 Trans Am


Driving the car with new diff fluid made an improvement, the wine at higher speeds was gone completely, but a new rattle like sound in the driveline is now apparent, a completely new sound, though quieter than the previous one. This sounds like a metal ring bucking back and forth or spinning around a shaft. I have not addressed it yet but further research it may be that the Torsen just makes this noise. It is only present when deaccelerating or letting off the gas at low speeds. It definitely has something to do with the thrust against the rear diff. My plan in the fall is to take the drive shaft out and take it to get new U joints to see if that solves the latest noise issue. If it doesn’t, I will wait until spring, change the diff oil again and reverify there is nothing bad going on inside. From what I read the Torsen diff’s are just noisy, and the 4th gen forums as well as ls1tech recommend replacing the rear axle with an aftermarket 9″ as the solution. I may just have to do that in 1-3 years if this noise doesn’t sort itself out.

The only other complaint is the car stance is slightly off, the rear feels a bit too low. Some weekend I will jack of the car and add a 1/2″ spacer to the spring upper rubber pads to lift the back a touch. A half inch will go a long way I think.

Next post will cover the Apple Carplay/Android Auto system with rear backup camera installed in this 2000 Trans Am, as well as back to projects for the 1981 Trans Am which includes a RetroSound Daytona M2 radio and New Vintage USA gauges. Stay tuned!

Strano Springs and Koni Shocks, new brakes, bump stops, an adjustable panhard bar, and rear lower control arms in 2000 Trans Am

This spring I replaced the shocks and springs in my 2000 Trans Am with Koni STR.T shocks and Strano SP141 springs. installation was fairly straightforward, though while I had the front suspension apart I replaced one of the wheel bearings which promptly failed within a few miles leading me to replace it again! I also replaced the rear bump stops, all 4 brake rotors and pads, replaced the rubber hoses, and bleed the brakes. First, the results are excellent. While I had the car apart I replaced the sway-bar bushings as well as the rear lower control arms, panhard bar with an adjustable panhard bar, and installed new bump stops in the rear as the originals were completely destroyed after 20 years of use.

2000 Trans Am with Koni STR.T shocks and Strano SP141 springs

It does appear the rear is about 1/2″ lower than the front, but I have measured the bottom of the car and it’s the same height off the ground all around, it is just the lines of the car give the appearance that the rear is lower than the front. Ride wise, the handling is rough but not as rough as it was previously. If you look at the previous suspension, you can see that the previous owner upgraded the lowering springs but kept the original orange shocks, which may explain why the shocks were all but dead and ride was beyond harsh with the rear bottoming out on nearly every bump.

2000 Trans Am with original orange shocks and aftermarket lowering springs
2000 Trans Am with original orange shocks and aftermarket lowering springs

The rear bump stops were completely chewed away leaving the axle to literally bottom out against the bottom of the car metal to metal.

2000 Trans Am with aftermarket lowering springs with bump stops completely worn away

While I had the brakes apart I went ahead and painted them with a Por-19 brake caliper paint that I brushed on. It holds up nicely but if I did it again i would use a rattle can paint as these calipers have smooth sections which lead brush strokes being visible when up close. From 5+ feet though the calipers look pretty good, which is fine for me. I also upgraded the rotors to Centric brand that have a special coating to prevent rust. I figure since I will be keeping the car for many years with minimal driven miles, if I can keep the rotors from flash rusting that would be a bonus.

2000 Trans Am with new Strano springs and Koni shocks, coated Centric calipers and Hawk pads
2000 Trans Am with new Strano springs and Koni shocks, coated Centric calipers and Hawk pads
2000 Trans Am with original orange shocks and aftermarket lowering springs
2000 Trans Am with original orange shocks and aftermarket lowering springs

I also converted the bump tops from the factory rubber to Suspension Techniques polyurethane versions. They worked out great with a 1/2″ aluminum spacer. Will cover this in a separate post.

Other details include a new rear stabilizer bar as the one I removed had rust at the bushing locations, the rear drivers caliper replaced with a reman unit due to the bleeder screw hole being stripped and other things like fresh brake fluid. In a future post I will write about the rear axle noise I had after I installed a new Borla exhaust system with a cutout, which lead me to replace the rear axle shafts and new bearings as well as new rear parking brake shoes only to find the sound is still there and more than likely an artifact of the 2000-2002 rear diffs being a Torsen style rather than an Auburn style rear diff. Following that I will post the installation of a Sony XAV-AX150 in dash Android Auto/Apple CarPlay receiver with a 7″ display. Stay tuned for those updates!

New Tires, Borla Exhaust and Electric Cutout at Y pipe on 2000 Trans Am

The exhaust system in the 2000 Trans Am was modified by the previous owner with a Y pipe-back LoudMouth system, and boy is it loud. Last year I took the car to MadHatters in Columbus and they replaced the LM muffler with a Magnaflow. They gave me the previous muffler, which was noting more than a bulge in an otherwise hollow pipe to provide the appearance of a muffler, most likely to pass an inspection. The System had a lot of drone, specifically around the 1,500 to 2,200 RPM range which led me to shifting early or late to avoid the drone, which is absolutely no fun. The Magnaflow solved the drone issue but it still didn’t sound all that great, just loud.

Borla 14780 3″ Adjustable Cat-Back Exhaust System

This spring I purchased the Borla 14780 3″ Adjustable Cat-Back Exhaust System. I wanted dual rear tips and the ability to adjust the loudness with the various plates provided in the kit attracted me to it, and Borla makes a very good quality sounding exhaust system. The bolt pattern is 3 bolts similar to what header collectors and electric cutouts use, which got me thinking that an electric cutout could be bolted in. After a quick search, not only can it be done, folks have been doing it since the 90’s! After doing some research I purchased an electric cutout from DMH.

Borla 14780 3″ Adjustable Cat-Back Exhaust System with dual exhaust tips on a 2000 Trans Am

As pictured, the dual tips on the Borla system are just awesome. Sound wise, the car sounds perfect inside, no drone at all. When the windows are closed it does not matter if the cutout is open or not, you get about the same loudness inside the car. The biggest advantage to closing the cutout though is at the drive thru line. I see no benefit of having the system partially open, either it’s closed because I am trying to talk to someone or its open. Best part is the sound inside the car is now normal, maybe too normal as I then started to pickup sounds from the rear diff which leads me to the next post covering the work I did to rear axle.

The previous LoudMouth system also had dual tips and looked good, but these Borla tips are something else. I would love to know if the tips also help with the quality sound from the Borla system or if they are simply for show.

Comparing Borla dual exhaust tips to Loud Mouth exhaust tips

Electric Cutout for the Borla 14780 System

I ordered a cutout from DMH based on recommendations on the various 4th gen forums. I was going to get a cutout from Quick Time Performance QTP QTEC30B / QTEC30 but after talking with the guy from DMH, I decided it was worth buying locally (from Ohio) and a nice guy on the phone. When it arrived however, I was expecting the rectangular switch from the pictures on his website and description, instead I got the round 3/4″ momentary switch, exactly like what is in the QTP cutout. Lesson learned but the same day I ordered the DMH I ordered a plate on eBay to mount the rectangle switch in my ashtray based on measurements from DMH’s website. I called DMH and he said he would ship me the rectangle switch described on the website. After waiting 3 weeks, I decided to order another plate from ebay for the ashtray this time with the 3/4″ hole instead of the rectangular cutout. The seller on eBay rocks, he got the plate to me in 2 days both times! The correct switch from DMH never came. Truth be told, I prefer the round switch as it is a bit lower profile and has a clean look in the center console.

I think the DMH cutout is good quality, but my experience with not exactly getting what was pictured rubbed me the wrong way at the time, and never getting that replacement switch was irritating. I will likely get a Quick Time Performance cutout if it ever needed one again, or if I order from
DMH I will have 20 questions ready to make sure I am getting what I think I am getting.

Installing the Borla 14780 System

I can’t say I am an exhaust installation expert, but I have replaced a dozen exhaust systems over the years with various degrees of success as well as a failure or two. The Borla 14780 3″ Adjustable Cat-Back Exhaust System was the most straight forward and easiest I have ever installed, and this is a system with multiple pipes and hangers. I’ve had harder times installing just a muffler! I was able to loosely bolt the system together then slowly move connections here and there to get it to fit perfectly. When I say perfectly, I mean perfect, perfect clearance over the axle and through the special angle built into the car between the pan-hard bar and the pan-hard bar structure. They took good care on clearances, every pipe slid on snugly, I only had to massage the pipe that transitions to the factory Y pipe slightly to get it to slide on, but that should be expected since the previous system used a traditional U clamp.

Wiring for the electric cutout and switch in ashtray

Wiring for the electric cutout was rather straight forward. While I had the car apart I took the opportunity to also run backup camera wiring along with the cutout wiring. I added a very small hole in the rear spare tire well on the inside and fed the wires through and added my own mid-point weather pack connector to make it easy to connect/disconnect at the spare tire. If I need to switch out the cutout, I can switch to another brand and simply re-splice the wires to a weather pack connection under the car and plug it right in.

Wiring is straight forward, you need a power source to the switch, then the switch has its own wires that run to the back of the car where the cutout is positioned. I used the accessory ignition tap connection from the fuse box and ran the wire under the ash to the center console. It is a tight fit, I had to cut a little bit of the top GM tap wire to get it to fit the Velcro fuse box cover.

I located the switch in the ashtray. I do not smoke, converting the ashtray to something useful was a no brainer. The plate simply lays in the ashtray. I did not glue it or do anything permanent, someday if/when I want the car all original I can pull the switch and wiring and put the ashtray back in. Honestly though I think the next owner will also prefer the cutout switch over an ashtray.

Electric cutout switch for Borla exhaust on Trans Am in center console ashtray

The switch on the left is yet to be wired, but I am planning on adding something in the future that I will turn on/off. More on that next year.

Michelin Super Sport 245/40R18 tires

The previous owner, I believe in 2008 upgraded the wheels and tires on the Trans Am. The 18″ wheels are actually pretty cool, Halo HE834 18×8. I did some research and found they weigh 22lbs, which is comparable to anything I would buy today to replace them. Since they are in nearly perfect condition, I decided to keep the wheels and get new tires. After shopping around I decided on Michelin Pilot Super Sport 245/40R18 tires from Costco. These are summer tires only, which is fine as I do not plan on driving this car in weather when it’s below 40 degrees and never ever in snow. What a difference the tires made! I purchased the tires first before I started the suspension, brakes and exhaust work. Of the modifications made, this had the most dramatic improvement. The previous tires were on year 12 according to the date stamped on the rubber. Even though they had plenty of tread, they just didn’t feel right and now that I have new rubber on the car I know why. These Michelin tires stick to the road like no ones business. Maybe too sticky! With the previous tires I could do burnouts and side the rear easily, maybe too easily at times. These Michelins provide nothing but grip, now I have to really put some effort to get the wheels to chirp. If your tires easily slide and slip and its really easy to to burnouts, its time for new tires!

Michelin Pilot Super Sport 245/40R18 tires with Halo HE834 18×8 rims on 2000 Trans Am

Next post I will cover the suspension work I did, including replacing the brake pads, rotors and replaced the shocks, springs, and bushings.

RetroSound Daytona M2 installed in 1970-1981 Firebird Trans Am

Earlier this year I ordered a new RetroSound Daytona M2 radio for my Trans Am to go with the recently acquired 77 dashboard. For those who are not aware, the 70-77 dashboards and the 78-81 dashboards are identical except for the size of the radio opening. In 1978 GM changed the radio size to be narrower, about the height of the newer 1 DIN standard we have today. With the 77 dash I got, the radio opening is slightly higher and since this dash I got was not cut, I didn’t want to cut the better dash up to transfer the CD player over, instead I acquired a more period correct looking radio, the RetroSound Dayton M2 to be specific.

First, take a look at the Aiwa receiver I had in the Trans Am. I believe I purchased this radio in 2003-2004 for my car at the time because it had a high output amp (over 50W x 4), an aux input jack, and it could play mp3’s from CDs essentially expanding the songs I can have on a disc from 12-18 to 120-180. It’s still a great radio but today we have features like Bluetooth and USB ports with a limit of 100,000 songs.

Aiwa CD mp3 player with aux input jack in 1981 Trans Am

The 1977 dash I acquired is red and will soon to be changed to Laudau Black to match the rest of the interior. Other than a couple spots where there are little dents, the dash is in great shape compared to my current 81 dash with the sink hole found under the carpet cover I have on it.

I purchased a new 70-77 stereo bezel and test fit the new RetroSound Daytona M2 radio, it installed like a glove! The RetroSound kit includes a thick strap similar to a pipe strap which I used to attach the back of the stereo inline with the center screw used to hold the ashtray to the dash frame. It works perfectly, the radio is very stiff mounted with just that strap and the 2 radio knob threaded shaft points with the low profile nuts. The knobs cover the nuts and the threads without issue, just like the older radios did in the 60’s and 70’s.

I believe I ordered the kit with the chrome radio knobs, I then ordered a 2nd set of black knobs (4 pieces total) and used the chrome knobs for the back knobs and the black knobs for the front. It gives the radio a clean period correct look. The knobs are heavy steel, which at first felt too heavy but once installed they give you a very positive quality feel to them where-as the cheap plastic knobs commonly found during this time period feel cheap.

Over the winter I plan on installing the newer dash when I install a Vintage Air air conditioning kit. Until then, I decided to pickup a 78-81 radio bezel and for now I installed the RetroSound Daytona radio in my 81 dash. It looks great and only required moving the knobs outward about 1/4″ on each side.

1981 Pontiac Firebird Trans Am dashboard with RetroSound Daytona M2 radio installed

The RetroSound Daytona radio includes 2 aux input jacks as well as 1 USB jack that you can run to your glovebox or let them slide out under your dash. To provide a cleaner look, I purchased an USB and AUX flush mount dash extension panel at the rear of the center console. I picked the rear of the center console because it is not hard to find that back plastic panel found on the back of the 70-81 center consoles, and it is a location no one will notice the jack unless they are literally in the backseat and looking for it.

1970-1981 Center Console back panel with USB/Aux input jack installed for RetroSound Daytona radio

My interior lighting is white. It only took a few taps of the dial and I converted the radio to match the same white color.

1981 Pontiac Firebird Trans Am dashboard with RetroSound Daytona M2 radio with white backlit gauges

Even though the Daytona model is intended for 70-77 dashboards, I would not hesitate to recommend this model also for 78-81 Firebirds and Trans Ams as well.

The RetroSound’s sound quality is excellent. Even though the radio is slightly less powerful than the Awia (45W x 4) it replaced, the volume powers the speakers perfectly and now I have the perks of handsfree calling, Bluetooth, USB drive full of mp3’s, an Aux jack, and now the radio looks period correct too! Great job RetroSound!