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After 3 broken stock axles and a long wait from dss I finally got a chance to make a pass at full power Saturday . I didn’t even make it to the 60’ until something let loose in the diff. What are our options on replacement /repair? Case isn’t cracked and the car still moves under it’s own power. But it’s obvious that something is broken in the rear .
I am working on building a 4 pinion rear diff setup with member JHEBERT. We will be the only ones with them. That couples with 300m stub shafts available from Jeremy at RPM Transmissions and the same DSS axles you have. The problem is we had to find a machinist that could do the carriers and he isn’t looking to do anymore.
So you have two options here:
1) find a machinist to custom drill your carrier, a second pin, and custom make a billet box, all while locating a second set of unicorn spider gears that are NLA from GM
or
2) replace the rear diff with a 2019 model which is reportedly stronger based on a new tooth profile as per Tadge. Though we’ve not seen what the guts of the 2019 look like, they are supposed to be stronger. The rear diff was redisigned for the ZR1 and to keep it simple they use that design on all 2019’s and forward C7’s.
I will update this soon, we are waiting on 2 series and 3 series carriers from Albert, who is having the blocks made and carriers machined on CNC. The blocks dimensions where supplied by Ed (div7racer) and we have all been off and running with it. You can do 4 c6 spiders (the zr1 units are best but list around 150.00ea.) or the best way is using 4 c7 zo6 spiders. Good luck obtaining those, and it’s for this reason we don’t push this more.
About 2 months ago, a member with a z51 that cuts 1.3x 60’s broke his diff, we fixed that one using 2 c6zr1 spiders with new c7 side gears and rpm 300 stub shafts. I used the smaller ZR1 pin and bushed the carrier instead of boring the hole in the gear bigger. Way stronger the way I did his, and he hasn’t broken it yet...I would have gotten the call before the car was on the trailer.
If you have the coin for it, rpm is ready to go now with wavetrac units.
John
Has anyone had bad reviews of the wavetrac units? Unfortunately I don’t have any friends in the machine business that would have the time to mess with such a project.
I suppose you have a third option - go with a WaveTrac diff. Let me know how that works out for you though at your power level
What is wrong with the wavetrac other than the cost. I have the wavetrac in my car works great also have the 300 m input axle with the E-FORCE axle also.. Robert
Last edited by robert miller; Jul 2, 2018 at 04:45 PM.
Nothing wrong with it, EXCEPT the cost...it’s not like you can call wavetrac and have it sent to your house for a grand like the other units. IF and when GM can get the spiders for us, this mod can be done to a non broken diff for less than 500.00 in parts, and a couple hundred in machining. Retains full elsd operation, and uses all GM parts with the exception on the billet support block.
What is wrong with the wavetrac other than the cost. I have the wavetrac in my car works great also have the 300 m input axle with the E-FORCE axle also.. Robert
Wavetrac for me. Strapped mine on a pallet and sent it to them. Was about three weeks total
with shipping. With hardened stub axles it was around $2,800.
Wavetrac for me. Strapped mine on a pallet and sent it to them. Was about three weeks total
with shipping. With hardened stub axles it was around $2,800.
What gear ratio did you go with in the car. I have a A6 trans & went with the 3:42 gears polished from RPM..
Broken diff. What are my options?
What is wrong with the wavetrac other than the cost. I have the wavetrac in my car works great also have the 300 m input axle with the E-FORCE axle also.. Robert
Lets not go to that point, But I am sure you will maybe getting some of my money. Robert
