Featured Differential Overhaul and Winter Projects

[Jr. Corvette]

Hey Guys.

Well another winter’s underway and I have some more projects in the works. I decided to start a post showing the work I’ll be doing. This includes a differential rebuild, new custom rear upper strut install that a racer from BC made for me, A/C install, custom rear corner 6x9 speaker boxes for some new polk speakers, and a front one piece super spoiler.

The differential is the first stage of my winter build and I’m getting a later start on it because I was busy rebuilding a T56 Magnum for a guy to put in his 68 Camaro.

I’ll be rebuilding the diff with Tom’s 30 spline side axles, 30 spline spider gears, and new clutches and 400lb springs. I wanted to get the assembled unit from Tom’s but unfortunately they don’t have as much as they use too so that’s why I’ll be rebuilding my original posi. Although I have heard that the strongest cases were from 72-79 as they are thicker. I’ll be polishing the case to prevent cracks. I’m also going to swap out my 3.55 gears for Richmond 3.90’s as it’ll give me better acceleration and a useable 6th gear for cruising. My front differential mount also needed to be modified as the T56 caused the driveline angle to be thrown off and I don’t have enough adjustment on the mount to get it within specs. So that was just finished today and I’ll be picking it up tonight.

I have all of my parts on order so I’ll be starting the rebuild soon.

 

[RockyPM]

Going to love watching your progress Cody. Amazing what you are doing and the car is going to be fantastic! What do you think your mileage will be with the rebuild and different gearing?

 

[teamo]

Great work, looking forward to following along.

 

[YFCvii]

There are people who do the work and those that just take the credit.
Cruising with you is icing on the cake of watching your projects like this.
You had me waiting anxiously for every follow-up update to
last year's project on FB @Jr. Corvette .
Absolutely entertaining for someone who can only dream of doing this.
Thank you for posting this one on CCF as I know it takes a special person
to post messages while tasks are in progress of getting 'er dun.

 

[Jr. Corvette]

Going to love watching your progress Cody. Amazing what you are doing and the car is going to be fantastic! What do you think your mileage will be with the rebuild and different gearing?

I hope to get 11L per 100km highway after the swap. Last year on our cruise I was using 5th for the majority of our trip because 6th put me at 1600rpm going 120kmph. However I still managed to get 12.4L per 100kms and that was on my still new engine. Just after the cruise I passed 3000 miles on the engine and was able to swap over to synthetic.

@RockyPM @teamo @SN-III

Thanks guys! I really appreciate all of the support.

 

[turbozig]

Another fantasic project professor Cody. Looking forward again to watch your project progress through the stages, all the best!

 

[Jr. Corvette]

Merry Christmas everyone!

Got my part back from the welding shop. Unfortunately I think that’ll be that last time I go there. This is the second part they have screwed up. The first part I got welded there was a bung in my transmission for a sprayer and it had a pin hole in it which caused an annoying leak. This time when they were modifying the front diff mount they drilled the holes in the wrong place. Thankfully I noticed when I picked it up and they were able to fix it within an hour. However, they warped the part so badly it took me 4 hours with a sledge hammer, vice, and grinder, to correct the warp.

Anyway, here are some pictures of the mount cleaned up and ready to be sent off for powder coating. The first picture of it in the vise shows how warped this part was. Between a 1/4”-1/2”.

I have all the parts from Tom’s Differentials I’m just waiting on the richmond gear and pinion which should be arriving on the 15th. Then I will start on the rebuild. In the meantime I’m working on some corner speaker boxes that are going on top of the wheel wells in the corners of the rear interior.

 

[turbozig]

Merry Christmas everyone!

Got my part back from the welding shop. Unfortunately I think that’ll be that last time I go there. This is the second part they have screwed up. The first part I got welded there was a bung in my transmission for a sprayer and it had a pin hole in it which caused an annoying leak. This time when they were modifying the front diff mount they drilled the holes in the wrong place. Thankfully I noticed when I picked it up and they were able to fix it within an hour. However, they warped the part so badly it took me 4 hours with a sledge hammer, vice, and grinder, to correct the warp.

Anyway, here are some pictures of the mount cleaned up and ready to be sent off for powder coating. The first picture of it in the vise shows how warped this part was. Between a 1/4”-1/2”.

I have all the parts from Tom’s Differentials I’m just waiting on the richmond gear and pinion which should be arriving on the 15th. Then I will start on the rebuild. In the meantime I’m working on some corner speaker boxes that are going on top of the wheel wells in the corners of the rear interior.

Merry Christmas Cody. Sorry to hear about your crappy welding shop, I so feel your pain. Nothing worse when you bring something so easy and straight forward to a shop and they screw up, and destroy you part in the process. It is so hard to find someone that takes pride in their work nowdays. I am glad you got it straightened out in the long run. Best of luck with the rear rebuild!

 

[Rruuff Day]

Merry Christmas everyone!

Got my part back from the welding shop. Unfortunately I think that’ll be that last time I go there. This is the second part they have screwed up. The first part I got welded there was a bung in my transmission for a sprayer and it had a pin hole in it which caused an annoying leak. This time when they were modifying the front diff mount they drilled the holes in the wrong place. Thankfully I noticed when I picked it up and they were able to fix it within an hour. However, they warped the part so badly it took me 4 hours with a sledge hammer, vice, and grinder, to correct the warp.

Anyway, here are some pictures of the mount cleaned up and ready to be sent off for powder coating. The first picture of it in the vise shows how warped this part was. Between a 1/4”-1/2”.

I have all the parts from Tom’s Differentials I’m just waiting on the richmond gear and pinion which should be arriving on the 15th. Then I will start on the rebuild. In the meantime I’m working on some corner speaker boxes that are going on top of the wheel wells in the corners of the rear interior.

Merry Christmas back atcha Cody.

 

[Jr. Corvette]

Hey guys.

Been a little while since I posted so I thought I would do a little update. Unfortunately I haven’t made huge progress because I got the flu before Christmas and then a cold after the New Years so I haven’t gotten much done.

I’ve completely disassembled the differential and have cleaned all of the parts, even though I won’t be reusing anything other than the case and carrier. Right now I’m polishing the carrier to prevent cracking. Then I’ll be taking it to get machined to fit the new, bigger axles. Then I can start rebuilding it.

I took the new axles to a local Calgary company and got them coated in Cadmium so they won’t rust. I really like the finish. A very light silver that I think will go well with the powder coated silver drivetrain. The new axles use flanges instead of U-bolts so I had them powder coated then I took them and the half shafts to the drivetrain shop to get the U joints pressed in. I’m still waiting for the differential mount to be powder coated but hopefully I’ll have it and the half shafts back this Friday.

More updates to come soon.

 

[Rruuff Day]

Hey guys.

Been a little while since I posted so I thought I would do a little update. Unfortunately I haven’t made huge progress because I got the flu before Christmas and then a cold after the New Years so I haven’t gotten much done.

I’ve completely disassembled the differential and have cleaned all of the parts, even though I won’t be reusing anything other than the case and carrier. Right now I’m polishing the carrier to prevent cracking. Then I’ll be taking it to get machined to fit the new, bigger axles. Then I can start rebuilding it.

I took the new axles to a local Calgary company and got them coated in Cadmium so they won’t rust. I really like the finish. A very light silver that I think will go well with the powder coated silver drivetrain. The new axles use flanges instead of U-bolts so I had them powder coated then I took them and the half shafts to the drivetrain shop to get the U joints pressed in. I’m still waiting for the differential mount to be powder coated but hopefully I’ll have it and the half shafts back this Friday.

More updates to come soon.

That looks really good Cody. And thanks for posting. Nice to hear something besides repetitive C8 news for a change. lol....

 

[RockyPM]

Looking good Cody. C3 owners as well as the rest of us are watching your progress and cheering you on.

 

[YFCvii]

I am glued to and continue to watch because I know the “Actor” and he has the ranking of “Millennial Awesomeness” by taking on so much on his own

 

[Jr. Corvette]

Hey guys,

More updates on the differential. I got the differential mount back from being powder coated and I'm very happy with how it turned out. I also got the flanges and half shafts back from the driveline shop but I don't have pictures of it yet.

I got the carrier back from a machinist that lives just a few doors down from me. He took it to his work and machined the case axle openings slightly bigger for the bigger 30 spline Tom's axles. I finished polishing and radiusing the carrier then started the rebuilding it, adding better solid steel clutches and the new 30 spline gears and spiders. I got the clutches shimmed then added the factory 200lb springs. I had the option to leave the springs out, go with 200's or 400's, so I chose the happy medium. Next I installed the new 3.90 ring gear with ARP bolts, then installed the bearings.

On the differential housing I had to drill out the gear side bear cap holes and re-tap them for bigger 1/2 bolts for a stronger steel cap. Once that was done I installed the pinion races and then began the long process of shimming the pinion. I decided to go with a solid spacer over the crush spacer as it has a few benefits. Once I got the pinion setup for 22inlbs of rotational force I had to check and shim to achieve the right pinion depth. Got that all done so it's time to install the new carrier. I installed it using the factory case shims and it was spot on. I could run between 0.007"-0.009" of backlash and I had 0.008". Checked the pattern and I'm very happy with it. It's fairly centered and slightly favors the heel of the gear, but as more power is applied it actually will crawl up towards the toe, so favoring the heel is desired.

Just have to install the side bearings and seals. Then I'll just be waiting for the new pinion flange to get back from being powder coated as my old flange had a crack in it. Then I can put the differential back in and start to install the custom upper struts!

I got a new phone so these are all of the pictures I can get to upload. I will add more soon.

 

[RockyPM]

Amazing work Cody and great how you explain it so clearly i think i could do it. NOT!! Can't wait to see the car in the spring!

 

[turbozig]

Absolutely fantastic work! I foresee much much more HP in your future with the new rear and transmission mods. Supercharger or twin turbos next year?

 

[Jr. Corvette]

Absolutely fantastic work! I foresee much much more HP in your future with the new rear and transmission mods. Supercharger or twin turbos next year?

Thanks Ziggy. Hopefully a vortech supercharger next year!

 

[Jr. Corvette]

Here are the rest of the pictures. Had to compress the photos to make them load.

 

[Tango]

If you don't have yellow marker to check the gear pattern I put anti-seize.

 

[Jr. Corvette]

Hey everyone,

Hope you all are doing well and staying healthy.

I just realized the other night that I hadn't updated this thread in a while.

I finished up the posi and installed the new 30 spline axles that I had cadmium coated. I installed the bracket that bolts onto the diff for the new upper struts. Then I installed the differential back into place and bolted on the altered front diff mount. I made a custom spacer for it using a new polyurethane bushing, an old bushing that I cut in half, and some washers. I was able to get the operating angle to 0.12 degrees. A huge improvement to what it was before. I had to drill and install some mounts for the upper struts that go on top of my trailings arms. Once that was all done I finished bolting everything together. I took a couple videos of the movement in the rear end of my car before and after the upper strut install (their on my Facebook/instagram page if you'd like to check it out). You can really see the difference. Before when I pressed on the rotor the entire side moved in and out about 1/8" to 1/4". Now there isn't any movement and the camber curve has dramatically improved. I can't imagine how much better it is going to feel, going down the road without the rear wheels moving that much. Link to the video ()

I also got a new front spoiler and got some matte vinyl wrap. It took me about 7 hours to wrap the spoiler but I'm really happy with the result. I got it bolted on and I like how it looks. I feel it gives it a little bit more of an aggressive look without ruining the flowing body lines. I also feel that it makes the car look lower than before. Hopefully it will also add some downforce on the highway and reduce the drag coefficient.

My fan shroud had a clearance issue reducing the amount of camber I could have on the front end. I clearenced the fan shroud and adjusted the front camber. It went from around 0 camber on the right side and plus 2 degrees on the left side, to negative 1.2 degrees on both sides. I'm also going to adjust the rear so that I have negative 1.0. That should give me some better handling without causing excessive tire wear.

I also got all of the parts to rebuild my factory A/C system. I ordered a new and better compressor, condenser, evaporator, drier, and all the fixings.

I had to replace my slave cylinder that had only 800miles on it. It was a LUK cylinder, and from what I found they are known for leaking. I replaced it with a new Centric slave cylinder. Interestingly enough, the LUK had a composite housing like OEM but this new Centric is aluminum. I hoping that is an improvement but I guess only time will tell. I'm sure happy when I swapped in that T56 that I kept the 95-97 Camaro style pull clutch. If I had converted to the new push style clutch I would have had to pull the entire transmission to swap the slave. With this design I have limited options but I had the slave replaced and bled within 30 minutes.

I ran into an issue with the new Ridetech front shocks that I ordered. I went on Ridetech's website to find the OEM specs for the shocks. With my car being lowered I knew I needed to order some slightly shorter shocks so that I didn't bottom them out. So I ordered some identical shocks that were shorter. Come to find out when I went to install them that the T-bar that bolts to the lower control arm was too short. I went back to Ridetech's website and realized that they had a mistake on the specs they listed. I contacted Ridetech and JB power who I bought the shocks from. In addition to an email to Ridetech I decided to call them and had a terrible chat with a sales rep who didn't want to help in any way. Fortunately I heard back from JB power who agreed to return them and added the proper shocks to the website so I could order them. I never heard from Ridetech regarding the mistake on their website but a few weeks later I noticed they fixed the mistake. I like Ridetech shocks and they look really well designed. However, if your going to buy Ridetech, avoid buying it directly as their customer service sucks.

Anyway, I will try to keep you guys updated more frequently on the progress I'm making so I don't have big long posts that are a bit choppy like this in the future. I guess it's something to read while we're all in isolation . Thanks to everyone who's following along for the positive comments and support.