So last week I did the swap, and put in a 2008 z51 transmission and differential into my car, and the following is a few pics of in progress and things you need to take note of if you do the swap. All in all, I'd highly recommend anyone that is even slightly mechanically inclined to take the job on. I did in in 12 hours on jackstands, and this includes rerouting brake lines, shifter removal and reinstall, suspension components, and the like. The benefit I was looking for in this swap was the added strength of the tr6060 over the t56, as I am adding power, and the I also got the added unexpected benefit of a much nicer shift feeling. Gears just telepathically guide themselves into the next gate. It's great. Anyway, onto the description of the job.

The first thing to do is get the car up in the air, and I can say confidently that higher is absolutely better. I'd hate to do the job on a lift, but the rear bumper should be around 16 inches off the ground if possible - get pretty close to maxing out those garbage $12 dollar jackstands you haven't touched since the Obama presidency, as if the car is too low you WILL NOT BE ABLE TO GET THE TRANSMISSION OUT. You also may run into clearance issues with your shocks if the car isn't high enough when you slide the cradle out. In addition to the 4 jackstands holding up the car, I'd advise 1 more to help you position the transmission and torque tube when you're installing the new transmission.

Once the car is off the ground, disconnect all the rear suspension components from the body of the car. This is actually just your upper control arms and shocks. You'll also want to disconnect your brake lines and ebrake likes(you can't get the bracket out without loosening the axle nut - thanks GM) because all the added slack is needed when you're lowering the cradle.




Once the suspension components are disconnected, you'll want to disconnect every cable to the wiring harness you see as well. There's a large orange cable on the passenger side that connects in the rear wheel well, as well as a small black ground wire on the driver side wheel well that (I assume) grounds the leads for the fuel system. IF YOU FORGET THE SMALL BLACK WIRE YOUR CAR WILL NOT START. REMEMBER THE SMALL BLACK WIRE. There's also a sensor on top of the differential(speed sensor) and a few cables that connect to the transmission. There's the skip shift cable, the reverse light switch cable, and then one more cable I think. Disconnect them all. Be careful because they're 20 year old plastic. You can break them.

Next, you'll go after 8 and a half 13 millimeter bolts that connect the transmission to the torque tube. There's 7 regular bolts, and one bolt/stud combo that then has another nut stacked on top of it, bringing the total to 8.5 fasteners to remove. The wacky stud nut combo is at the 1 o'clock position looking from the back of the car towards the front. You will need a universal joint, and at least one extension to get to it. The harness is in the way and it generally sucks to get to.


You can see here where a few of the bolts are. Transmission on the right, torque tube on the left.

Zoom in and you can see the 8 holes on the torque tube that you'll be unbolting stuff from.

Once the torque tube is unbolted from the transmission, you're going to put 2 jacks in place. One is going under the front of the transmission, right before the torque tube, and the other is going to be sticking out the rear of the car, supporting the rest of the cradle and rear end. You NEED TWO JACKS, or at least a floor transmission jack(harbor freight didn't have it in stock so I used 2 jacks). It wasn't difficult, but I can't say how much easier using a trans jack would be. You need two because the differential has to be kind of massaged out (lift trans, lower cradle, slide 2 inches, lower trans a little, lift cradle, slide 2 more inches, and so on) from under the car, you can't pull it straight back because of the trunk compartment. Thanks GM. There are 4 nuts that hold the cradle in place. Support the cradle and transmission, then remove the nuts. I think they're 22 millimeter nuts. Apparently if you use an impact gun on them you risk breaking the fastener on the other side of the nut, and then you're really fucked. I loosened them by hand and then zapped them out.

Once the cradle and transmission are fully disconnected from the car and are only held in on your 2 jacks, you will lower the cradle slowly, until you clear the bolts and alignment pins that go from the cradle to the car. This is about 2 inches. Once it's clear, take the biggest prybar you have and get the transmission off of the torque tube. This is not easy. It took me almost 45 minutes to completely work the trans off of the torque tube. You'll have to adjust the two jacks to give you more clearance to roll backwards and pull it off the torque tube as well. Take your time, you really, really, really do not want to mess up the torque tube when you do this.
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Once the trans is free of the torque tube, you'll remove it from the car. The trans stays at the same height it was when it was connected, but the cradle is lowered all the way down, then you can begin to slide it out. It's useless walking you through it now because you have to see it to understand how the jacks must be adjusted to get it out. Simple but time consuming.

Once the trans is out, it'll look like this.


​​​Installation of the new trans and cradle commences. IMPORTANT: DO NOT FORGOT THAT THE SHIFTERS ARE DIFFERENT LENGTHS C5 TO C6. YOU WILL ASSEMBLE THE WHOLE CAR AND THEN YOU WILL HAVE TO UNDO IT AGAIN. DO NOT FORGET.


See? Imagine doing the whole swap and then having to undo it(I was considering rolling my car down the hill I live on and then taking an insurance check). USE THE C5 SHIFTER LINKAGE. THE C6 LINKAGE IS TOO LONG. USE THE C5 LINKAGE. There's a little roll pin you punch out then you can swap them.

Assembly is almost the exact same as removal, just opposite. I can't add much here, as I didn't take install pics, but I can give a few helpful pointers. Take your time sliding the trans into the torque tube. Aligning it on the two jacks sucks. You will get frustrated. It will not slide in. It will take you a hour or two to get it in. Make sure the input shaft is aligned with the trans(spin the brake with it in gear). Once it is aligned, you can push the transmission into the torque tube. Again, it's going to suck and take a lot of time. Just work at it slowly, and eventually you'll be able to use bolts to draw it together. When/if you do this, MAKE SURE THE ALIGNMENT PINS ARE IN PLACE. YOU WILL BREAK A PIECE OFF THE TRANSMISSION IF YOU TRY TO SCREW IT IN AND THE PINS ARENT LINED UP.

Also something you'll notice: you cant tighten the trans to torque tube bolts all the way without the cradle locked in place. You have to leave about 3/4th of an inch of space in order to raise the cradle into place, then you can tighten them all the way down. The goofy stud/nut goes in at the upper right, then the harness ground wire goes over it, then a second nut goes on top of it and is tightened down. Not sure what happens if you forget that particular ground, but I'm sure it's not good. Most of the trans sensors go straight to the harness, so nothing crazy. You may have a check engine light p08 something, that's because the skip shift solenoid doesn't line up and so you won't be able to plug it in(or maybe I broke my harness....oh well). This light can be safely ignored. Reach out to your tuner to turn it off, or do some research into making the harness plug in and enjoy being locked out of 2nd and 3rd gear.

After all that, you'll have to reroute your brake hardlines. **** the little line that runs across the C6 cradle. Chop it off and throw it away. Just run your hardlines from the car and work them into somewhere by your soft lines. The pic below is how I ran mine. Some(a lot of) massaging of the line is definitely required. Don't kink the line or you're in for a headache.



​​​​​You will disconnect your e brake cables and brackets from your old C5 rear end. As I mentioned before this necessitates axle nut removal for clearance. Install the old C5 brackets in place of the new C6 brackets. I'm sure you could make the C6 brackets work somehow but screw that. The c5 brackets work fine.

​​​​​I used a z51 trans, which means I have a fluid pump. If you have a Z06/r1/51 trans you'll have to do the same. I sawzalled the torque tube to clear my trans fluid pump loop.

I'm not going to list all the separate tools you'll need, but I'll point out a few that aren't obvious below.

More than 4 jack stands
More than one floor jack OR one floor jack and a transmission jack
Large prybar
​​​​​​Maybe a few C clamps to draw the trans to the torque tube.
Universal swivel for your wrench(maybe you don't need it, but trust me $15 at harbor freight will save you probably hours and you'll be less frustrated)

No I do not know what parts you need, I just used an entire C6 pullout rear end, which included all the suspension components (upper and lower control arms, leafspring, and shocks). Apparently you can use some of the c5 components to mix and match, but I don't know which ones. You'll of course need the offset mounts for the differential.

Absolutely feel free to ask questions below. I'll do my best to answer them. Shout out to Rick at rkt for helping me through the swap, even though I didn't buy anything from him.

​​​​​​​Riley

 

Good explanation and overview.

 

Did you just plug the TR6060 into the c5 manual transmission harness? Going from auto to manual so I’m trying to figure out the wiring issue.

 

Are you halfway through the swap? It seems that none of the c5 harness really connects to the tr6060 and diff, other than the speed sensor for the differential. I also didn't really try that hard to make the connections work. The cables from the harness are for skip shift(leave that **** unplugged) and for the reverse lights, which seems to not plug in. Different connectors, I'm sure you can get them to plug in with an adapter or something but I don't really care about it so I didn't bother. No clue at all what the harness looks like for the auto. Unless you've already bought the parts for the swap, honestly I'd sell the auto car and buy a manual. Sounds like a pain in the *** to get the other **** like the master, slave, clutch assembly, torque tube, pedal, and wiring figured out. Plus the automatic torque tube and trans/diff assembly really aren't worth ****, so you won't get a lot of money back on the old parts. If you're dead set on it and need a C5 shifter though let me know, I have an extra one.

 

Yea I already have a c6 subframe with diff trans and torque tube. Tick has the clutch, master, and any other shifter I need,(I need all&#128553 but I figured I was gonna have to splice a c6 manual trans wire harness with a c5. I have an extra auto harness do you know how much different that is from the manual?

 

Do work son

 

I don't have any experience working with the auto harness so can't say at all how different it is from the manual.

 

Any pictures of what you claimed to cut for the loop to clear? I couldn't picture that.

Sensors / harness connections - just swap over and connect your C5 sensors or cap/remove/secure any not being used.

Trans / Cradle mounts... I didn't see mention of what you used here. I presume single set of bolt holes for the 08 cradle right?

The swap is really easy. The only part I have not gotten to yet is cutting / welding the exhaust to clear and fit but my build isn't done and I am still partly debating which exhaust to use.

 

Yeah tomorrow ill take a picture of the (admittedly mangled) torque tube part I cut to get the loop to fit. Imagine a notch to clear the fluid loop. For the trans cradle mounts: there are no trans mounts. AFAIK the trans will bolt directly to the torque tube no mods required. Use the existing bolts. What do you mean by the single set of bolt holes for the 08 cradle? The cradle mounts in the exact same position as the c5 cradle with the exact same nuts. There are 4 downward facing chassis mounted bolts and two alignment pins on the cradle to line em up. I used the hinson motorsports offset differential mounts to make the swap work, there are 4 nuts for each mount(two mounts) for a total of 8 nuts to connect the differential to the cradle.

 

My error. 3am. I had meant the offset mounts for the differential tabs by the trans mount comment.

Did you go delrin or the softer material they offer?

 

Hinson doesn't advertise two different options, as far as I'm aware. The listing just says "High quality urethane". Here's the link to the page where I bought them. https://hinsonmotorsports.com/produc...smission-mount

 

Then that is a change because within the last month they had a Delrin specific listing on the page which is what made me curious over the "high quality urethan" option which has been out of stock consistently since then and prompted me to ask Rick if I should be concerned about the delrin mounts which I inherited with my cradle from a one-off manufacturer online as being any harsher than another or not. The response was it should be ok and no discernable difference in ride.

 

great write-up, looking to do the same this winter.

the only thing i would add, since i had to replace the differential last year on my 02.

( you have already disconnected the upper control arms / shocks. the rear disc can move and pivot freely on their lower mounts.)

use a large flat-blade screwdriver, place it be tween the side of the differential and each half shaft. apply gentle pressure and they will come free of the differential- use a jack/transmission jack to support transmission/ differential/ remove the rear cradle and set aside.

this will then allow you lower the the trans/diff with jack / transmission in one movement.
the while drivetrain pivots on the engine mounts. allowing the differential to come free avoiding the hump on the c5 and then the transmission if you want to take them apart in stages.

Do Not Lower beyond the recommended angle. c5 tunnel and shop manual have diagrams.


rear cradle removed. 3.90 from rpm in place ready for fin assembly

tran lowered, diff off. free from car

diff off and removed from car free of any body parts.

 

Wouldn’t be easier to put an M12 C5 Z06 trans on it?

 

Less expensive? Probably. Easier? No. The only thing you have to do differently for a tr6060 and C6 diff is install the offset differential mounts, the job takes the same amount of time regardless of what transmission you use. I got a screaming deal on my setup, $1600 for trans, diff, subframe, and suspension, so the M12 didn't make sense for me.

 

So I put in a manual harness and ended sticking with the auto harness do to not wanting to swap it again. Either will work, less bells and whistles will go off with the manual harness since the ECU isn’t looking for the 4l60. You still have to get the ECU flashed so you can utilize the clutch pedal switch from the neutral safety switch. Still haven’t figured out the cruise control and I’m not pulling my dash to swap that harness.😓

 

did u get it to work I’m wondering the same thing

 

There's nothing to actually plug in other than the reverse lockout solenoid, which I replaced with a manual spring loaded one for about $25 (sometimes the lockout fails and it's very difficult to get into reverse), the differential speed sensor for your speedometer, which plugs right in, and the reverse light harness - but you'll have to remove the t56 reverse switch and put it into your 6060 transmission. Then everything will work.

 

Yes and no,

Passenger sided I cut off and spliced in a manual temp gauge, driver side I de pinned and spliced in the yellow and purple wire for the clutch safety switch. You still have to get the PCM flashed over to manual for the clutch switch to work. If you don’t the only way to turn on the car would be to turn the key to run and bypass (hot wire) VATS solenoid in the passenger footwell. I still haven’t figured out the reverse lights or cruise control yet.

The wires are numbered and the schematic says which one to use. There are either two yellow or purple so check first.

 

Sorry, I thought he was going from a t56 to a tr6060. Auto to manual I have no clue, thanks for adding those schematics.