Need advice: C5Z ring and pinion
Thread Starter
Le Mans Master
Joined: Jul 2000
Posts: 7,638
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From: Greenville SC
Need advice: C5Z ring and pinion
I had the fluid changed in my diff today on my 02 C5Z, 60K miles. It was the first time I had this done, not sure it was ever done before.
Unfortunately there was grit and small chucks on the drain plug, and glitter in fluid. I think this was done by previous owner, as I am easy on the car, and it also needed a clutch when I got it, even though it had an aftermarket one in it. Car has a Procharger, cam, headers, and made 607whp/480TQ when tuned.
I don't do hard launches, drag racing or track, just some spirited back road driving, etc.
Mechanic recommends a hardened pinion.
I did a little research and it seems nothing is available as an easy replacement upgrade, and you have to change to a C6Z rear end. From an old thread:
"All after market ring and pinions for the C5/C6 are made by Motive in Italy. The other companies Yukon, Nitro, ECT are all reboxed motive gears. The corvette uses a very unique gear set that is very different than a standard RWD differential. "
A new stock set would probably be fine for me, but I always like to upgrade when something fails if there is a better item, and worth the price.l
What do you recommend?
Also, anything else "while I'm in there" upgrades, maintenance items?
Would a trans brace, ECS Torque Tamer, trans mount, etc. be worth it for me and help reduce breaking gears? I don't want the car to ride any harsher, I have DRM Bilstein shocks on now and lowered.
Unfortunately there was grit and small chucks on the drain plug, and glitter in fluid. I think this was done by previous owner, as I am easy on the car, and it also needed a clutch when I got it, even though it had an aftermarket one in it. Car has a Procharger, cam, headers, and made 607whp/480TQ when tuned.
I don't do hard launches, drag racing or track, just some spirited back road driving, etc.
Mechanic recommends a hardened pinion.
I did a little research and it seems nothing is available as an easy replacement upgrade, and you have to change to a C6Z rear end. From an old thread:
"All after market ring and pinions for the C5/C6 are made by Motive in Italy. The other companies Yukon, Nitro, ECT are all reboxed motive gears. The corvette uses a very unique gear set that is very different than a standard RWD differential. "
A new stock set would probably be fine for me, but I always like to upgrade when something fails if there is a better item, and worth the price.l
What do you recommend?
Also, anything else "while I'm in there" upgrades, maintenance items?
Would a trans brace, ECS Torque Tamer, trans mount, etc. be worth it for me and help reduce breaking gears? I don't want the car to ride any harsher, I have DRM Bilstein shocks on now and lowered.
.
Joined: Apr 2013
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St. Jude Donor '14-'15-'16-'17-'18-'19-'20-'21-'22-'23
Melting Slicks
Joined: Dec 2018
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From: Orange County, CA
I wouldn't immediately jump to major conclusions on the fluid contents. The LSD belleville springs are a known weak point, which can break into pieces that may show up on the magnet. And when that happens, the clutch packs will experience more wear that results in extra glittery fluid. You can check LSD condition pretty easily: 1) jack up just one rear corner, other on the ground; 2) trans in neutral; 3) spin the elevated wheel, if the wheel spins by hand or with less than ~30-50 ft-lbs of torque applied then the belleville springs / clutch packs are toast.
For reference my ~70k mile LSD was completely done for: https://www.corvetteforum.com/forums...post1601593264
For reference my ~70k mile LSD was completely done for: https://www.corvetteforum.com/forums...post1601593264
Thread Starter
Le Mans Master
Joined: Jul 2000
Posts: 7,638
Likes: 326
From: Greenville SC
Metalman2- OK thanks, that is what I have found too after researching more. I watched a video where they upgraded the springs to a C6Z spring, which are larger and stronger. I'm going to look into that more, but it seemed like it was just a straight forward replacement. The mechanic told me when I was there he would just like to have the car for a week and go through the diff to find the issue, and then go from there, which I agree is the only way to know for sure. I'm just trying to plan for everything now, and would like to upgrade things in that area to prevent future issues and repetitive repairs. I'm hoping it's just the springs and maybe clutch packs, and I can leave the rest in. Another video said since the bearings are large, they tend to hold up well, and seldom need to be replaced.
Right now I'm considering at least adding the AMT diff mount, and maybe an ECS trans brace. The bushings looked really good when I was working on the rear recently, was surprised how new they looked, but they are still 23 years old, so may consider changing.
Smoken1- FYI the part I quoted was from an RPM post.
Right now I'm considering at least adding the AMT diff mount, and maybe an ECS trans brace. The bushings looked really good when I was working on the rear recently, was surprised how new they looked, but they are still 23 years old, so may consider changing.
Smoken1- FYI the part I quoted was from an RPM post.
Melting Slicks
Joined: Dec 2018
Posts: 2,654
Likes: 1,386
From: Orange County, CA
Yep! They drop right in. Will definitely need a press and an appropriate tool to get everything installed. Old LSD parts may just slip out without the tool if the old belleville springs are in rough shape like mine were.
Instructor
Joined: May 2017
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I did the upgrade to the C6 clutches when I rebuilt my diff. I have one thing to say, use Mobile One diff fluid. I used Redline, Valvoline and Royal purple fluids. They were ALL noisy, even after I added the AC Delco friction modifier. The diff got quiet and smooth immediately after putting Mobil One in it.
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Melting Slicks
Joined: Dec 2018
Posts: 2,654
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From: Orange County, CA
I did the upgrade to the C6 clutches when I rebuilt my diff. I have one thing to say, use Mobile One diff fluid. I used Redline, Valvoline and Royal purple fluids. They were ALL noisy, even after I added the AC Delco friction modifier. The diff got quiet and smooth immediately after putting Mobil One in it.
https://www.corvetteforum.com/forums...post1601336528
https://www.corvetteforum.com/forums...post1602249099
Drifting
Joined: Jan 2008
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From: Florida
St. Jude Donor '09
Metalman2- The mechanic told me when I was there he would just like to have the car for a week and go through the diff to find the issue, and then go from there, which I agree is the only way to know for sure. I'm just trying to plan for everything now, and would like to upgrade things in that area to prevent future issues and repetitive repairs. I'm hoping it's just the springs and maybe clutch packs, and I can leave the rest in. Another video said since the bearings are large, they tend to hold up well, and seldom need to be replaced.
Melting Slicks
Joined: Dec 2018
Posts: 2,654
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From: Orange County, CA
OP is aiming to leave bearings untouched, meaning no change to clearances. This is the approach I took when rebuilding my LSD and it worked out great.
Drifting
Joined: Jan 2008
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From: Florida
St. Jude Donor '09
Melting Slicks
Joined: Dec 2018
Posts: 2,654
Likes: 1,386
From: Orange County, CA
Great idea, I guess we will just ignore bearing wear and/or damage. He reported the following in his original post: "Unfortunately there was grit and small chucks on the drain plug, and glitter in fluid." With his modifications, age of the diff and bearings, and condition of the oil, I would change the frigging bearings.
In my own personal experience, small chunks on a magnet doesn't necessarily mean bearing damage/wear especially since there's a good chance it's from the belleville springs. Similar deal with the glitter; that could just be clutch pack wear material that won't necessarily abrade bearing surfaces.
I had similar 'stuff' in my diff when I serviced the LSD @ 70k miles. I'm now @ 84k (5 years later) with no apparent diff bearing noise or otherwise, and feeling glad I didn't touch the bearings.
Drifting
Joined: Jan 2008
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From: Florida
St. Jude Donor '09
I've said my piece, as have you. Up to OP to evaluate and decide on path forward.
In my own personal experience, small chunks on a magnet doesn't necessarily mean bearing damage/wear especially since there's a good chance it's from the belleville springs. Similar deal with the glitter; that could just be clutch pack wear material that won't necessarily abrade bearing surfaces.
I had similar 'stuff' in my diff when I serviced the LSD @ 70k miles. I'm now @ 84k (5 years later) with no apparent diff bearing noise or otherwise, and feeling glad I didn't touch the bearings.
In my own personal experience, small chunks on a magnet doesn't necessarily mean bearing damage/wear especially since there's a good chance it's from the belleville springs. Similar deal with the glitter; that could just be clutch pack wear material that won't necessarily abrade bearing surfaces.
I had similar 'stuff' in my diff when I serviced the LSD @ 70k miles. I'm now @ 84k (5 years later) with no apparent diff bearing noise or otherwise, and feeling glad I didn't touch the bearings.
Thread Starter
Le Mans Master
Joined: Jul 2000
Posts: 7,638
Likes: 326
From: Greenville SC
I did the upgrade to the C6 clutches when I rebuilt my diff. I have one thing to say, use Mobile One diff fluid. I used Redline, Valvoline and Royal purple fluids. They were ALL noisy, even after I added the AC Delco friction modifier. The diff got quiet and smooth immediately after putting Mobil One in it.
So I'm going to go with the Amsoil again. The new trans fluid definitely helped the shifting, it had become very difficult to go in reverse.
I did select the Mobil 1 gear lube with additive for my 95 with the ZF6 diff.
Thread Starter
Le Mans Master
Joined: Jul 2000
Posts: 7,638
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From: Greenville SC
Metalman2 and ipuig, I appreciate the suggestions and info. I am "hoping" it is just the springs, but they are going to remove and inspect, so it may need other parts.
I'm going to plan for at least the C6 Z06 springs/clutch packs. I'll ask them about the Kent Moore tool.
I usually do my own work, but this is way more than I want to get into on jack stands, and I don't know enough about diffs to work on them anyway.
I have only used the shop a couple times, but they have been very good, and knowledgeable. I discussed with the overall manager a good bit, and he was knowledgeable, and has R&R'd several of these himself and described the process, and the shop manager is the one who works on my cars, and he is the one that pointed out the sludge. He just got a C4 and is doing a auto to ZF6 swap and building a 383. They are also ASE certified.
They are quoting $1600 to remove and inspect the diff etc., and then whatever the parts cost. I'm also going to get them to fix a leak in the front, I hope it is just the lower oil pan gasket, not the upper. I watched a video on removing the upper, and I could not believe how much had to be disassembled to get to it, and they rivet the gasket on, which also requires an alignment tool to install.
$200 for lower, $800 for upper.
I'm going to plan for at least the C6 Z06 springs/clutch packs. I'll ask them about the Kent Moore tool.
I usually do my own work, but this is way more than I want to get into on jack stands, and I don't know enough about diffs to work on them anyway.
I have only used the shop a couple times, but they have been very good, and knowledgeable. I discussed with the overall manager a good bit, and he was knowledgeable, and has R&R'd several of these himself and described the process, and the shop manager is the one who works on my cars, and he is the one that pointed out the sludge. He just got a C4 and is doing a auto to ZF6 swap and building a 383. They are also ASE certified.
They are quoting $1600 to remove and inspect the diff etc., and then whatever the parts cost. I'm also going to get them to fix a leak in the front, I hope it is just the lower oil pan gasket, not the upper. I watched a video on removing the upper, and I could not believe how much had to be disassembled to get to it, and they rivet the gasket on, which also requires an alignment tool to install.
$200 for lower, $800 for upper.
Drifting
Joined: Jan 2008
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From: Florida
St. Jude Donor '09
Safety Car
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From: Ex DPRK, now just N of Medford, OR
I wouldn't be in a giant rush to replace to R&P just for finding crap on the magnet...
Yes, check the LSD function. If it's failed, then take it apart and look.
If not, put fresh fluid in it. Does it make noise? No? Good to go.
Yes?
Well crap, I gambled $30 worth of fluid against the cost of a new diff.
As for needing all of the GM special tools to properly set up the R&P... No. But take it to a shop that specializes in diffs!
Most shops won't touch one, and send them out anyway. It's a specialty, and unless you do them often, it's a great way to lose money.
A 4x4 shop is a good place to start. They swap gears regularly, and if they don't build them, at least they'll know who does.
Yes, check the LSD function. If it's failed, then take it apart and look.
If not, put fresh fluid in it. Does it make noise? No? Good to go.
Yes?
Well crap, I gambled $30 worth of fluid against the cost of a new diff.
As for needing all of the GM special tools to properly set up the R&P... No. But take it to a shop that specializes in diffs!
Most shops won't touch one, and send them out anyway. It's a specialty, and unless you do them often, it's a great way to lose money.
A 4x4 shop is a good place to start. They swap gears regularly, and if they don't build them, at least they'll know who does.
Drifting
Joined: Jan 2008
Posts: 1,722
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From: Florida
St. Jude Donor '09
