Z/28 Parts List

[X25]

Looks like Z/28 differential assembly is #23172756. I found it for as low as $1050, which doesn't sound too bad, actually.

[Firefighter]

Originally Posted by X25

Looks like Z/28 differential assembly is #23172756. I found it for as low as $1050, which doesn't sound too bad, actually.

Is that the entire pumpkin? Gears/Diff/Housing/Cooler?

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[JusticePete]

Originally Posted by Firefighter

Is that the entire pumpkin? Gears/Diff/Housing/Cooler?

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There are supporting parts required - shafts and hubs.

[Firefighter]

Originally Posted by JusticePete

There are supporting parts required - shafts and hubs.

I figured as much. Better off throwing a Trutrac in my stock 1LE rear. Throw some billet caps and a cover with a fabbed up diff cooler if I ever go far enough to need it.

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[X25]

Originally Posted by JusticePete

There are supporting parts required - shafts and hubs.

Do we need shafts/hubs for 1LE, too? It would be nice to see if you know the list of what is exactly needed : )

From the pics of diagrams, it looks like the entire assembly (which has the cooler as well?) comes with it, but even if it has the cooler unit, I presume it won't have the lines to run it to the transmission.

[JusticePete]

I don't have the GM parts list in front of me but I can tell you that the part numbers listed by GM are different for the rear hubs and shafts even on the 1LE.

[kfiruta]

I have a 2015 1le and just got the z28 front splitter. Are there any mounting instructions available anywhere? Also do I need so type of mounting kit to install? I find it hard to believe it just bolts the the front bumper. Any help is much appreciated.

[JusticePete]

There is a 1LE owner I have been speaking with that may end up doing the complete aero package, heads, cam and differential. If this come together we'll do a very detailed write up.

[PYROLYSIS]

Originally Posted by JusticePete

There is a 1LE owner I have been speaking with that may end up doing the complete aero package, heads, cam and differential. If this come together we'll do a very detailed write up.

Awesome. Looking forward to it.

[JusticePete]

Originally Posted by PYROLYSIS

Awesome. Looking forward to it.

IF it comes together...

[kfiruta]

Great thank you!

[td195f]

Originally Posted by X25

Looks like Z/28 differential assembly is #23172756. I found it for as low as $1050, which doesn't sound too bad, actually.

Check your part number. I have the Z/28 Rear Diff Assembly Part number as 23172755 and I thought I got a pretty good deal at $2062.50. The number I have listed above is the number in the current Chevy Performance Catalog on pg 31.

The Z/28 Design Engineer I spoke with at PRI in Indy last December said that the 1LE half shafts would be compatible with the Z/28 Diff.

I'll definitely know for sure in less than a week when I install the new diff assembly.

In RadRace19's post in this thread #343 he says

"23172755 DIFFERENTIAL ASM is the whole case as a drop in unit.
23172756 DIFFERENTIAL ASM - is just the Torsen differential to be used with your Stock SS case and gears.
-Greg"

That would explain the price difference. If you want the whole assembly to bolt in, order 23172755.
You will also need the cooling lines to hook up the cooler. I bought the kit so I now have a spare cover with the cooler. I figure eventually I'll put a Detroit TruTrac in my 1LE housing and install the cover with the cooler and have a spare diff.

[X25]

Originally Posted by td195f

Check your part number. I have the Z/28 Rear Diff Assembly Part number as 23172755 and I thought I got a pretty good deal at $2062.50. The number I have listed above is the number in the current Chevy Performance Catalog on pg 31.

The Z/28 Design Engineer I spoke with at PRI in Indy last December said that the 1LE half shafts would be compatible with the Z/28 Diff.

I'll definitely know for sure in less than a week when I install the new diff assembly.

In RadRace19's post in this thread #343 he says

"23172755 DIFFERENTIAL ASM is the whole case as a drop in unit.
23172756 DIFFERENTIAL ASM - is just the Torsen differential to be used with your Stock SS case and gears.
-Greg"

That would explain the price difference. If you want the whole assembly to bolt in, order 23172755.
You will also need the cooling lines to hook up the cooler. I bought the kit so I now have a spare cover with the cooler. I figure eventually I'll put a Detroit TruTrac in my 1LE housing and install the cover with the cooler and have a spare diff.

Good info, thanks. I saw both numbers on parts store, but their description was misleading:

23172755 DIFRNTAL ASSY
W/ZL1, Z28, Z28, W/O LIMITED SLIP $2,732.97 $2,180.25
23172756 DIFRNTAL ASSY
W/ZL1, Z28, Z28, W/LIMITED SLIP $1,705.67 $1,127.79

Since it stated "without limited slip", I thought it would be the wrong part.

So, to recap, if we get 23172755, all we need is to add two lines and we are done? Do you know the line part numbers?

Alternatively, what is the best diff for our cars? For instance, I know that for Miatas, the best one is Quaiffe. Is there such a diff available (is it TrueTrac? )

[td195f]

Originally Posted by X25

Good info, thanks. I saw both numbers on parts store, but their description was misleading:


Since it stated "without limited slip", I thought it would be the wrong part.

So, to recap, if we get 23172755, all we need is to add two lines and we are done? Do you know the line part numbers?

Alternatively, what is the best diff for our cars? For instance, I know that for Miatas, the best one is Quaiffe. Is there such a diff available (is it TrueTrac? )

Ahhhhh.... If it was only that easy.I have the cooler kit and it lists all the part numbers. PM me with an e-mail address and I can send a copy of the parts list when I go back into work on Thursday. There's more than two lines that are replaced. The kit has about 8 different pieces of tubing to get from the radiator back to the diff and back into the transmission. The only lines you reuse are the line from the trans to the radiator and the two short lines into and out of the radiator with the rubber hoses. Getting the lines that run up and back from the radiator out of the car to replace one of them with a new line is a bitch!!!!! You have to work them around the AC and steering rack. I found opening the mounting brackets and taking the lines out one at a time was the only way they would come out. Typical GM instructions say "Remove the lines" with a note that says you may have to remove them one at a time, with no other info. The kit also includes all the required hardware such as hangers for the lines, mounting brackets, new bolts for the driveshaft and rear calipers, etc.

Yes, 23172755 is the complete unit. I have one in the box in my shop that I will be installing this weekend. I highly recommend the seal protector tool(special tool, outrageously priced) for removing and installing the half shafts without damaging the seals in the diff housing. I think the tool number is also listed in the cooler install instructions.

Eaton is now making a Detroit TruTrac Carrier for the 5th Gen Camaro Diff. It looks to me just like the Torsen in the Z28. All gears for the limited slip, no clutch packs.
The Z/28 Design Engineer that I talked to said one of the best upgrades I could make to my 1LE for track performance was the Torsen Rear Diff. He felt you would find a significant difference in performance from turn in to apex and during power application from the apex out.