lsxs13

My car is currently at a shop having the transmission replaced and a 3.90 gear installed. I have a 2006 base 6MT non Z51 car. The transmission was replaced with a rebuilt exact model trans but from an 07. The shop has ordered multiple gears from Summit which were Yukon brands and recently ordered a Nitro brand gear. None, however, will work with my car. It all sounds strange that nothing fits correctly. The shop will reinstall the factory 3.42 tomorrow and send me on my way if nothing can be figured out by tomorrow. I would say maybe the shop doesn't know what they're doing but they have worked on tons of GM cars and never seen this issue before.

The car did come with a built RPM transmission that was making a ton of whining noise. Maybe since it was upgraded the differential might have been swapped with something else. From what I researched the z06 has a different differential but easy to spot due to the diff cooler. Could the cooler be removed and just look like a base model diff from the exterior? I'm not sure if the stock z51 diff has a cooler or not, I just remember reading that the trans or diff is geared differently than a base c6.

The car had no other mods besides the RPM transmission that I knew about. I was told it was bone stock when purchased.

jim2092

Contact RPM they may have records on the car and tell you what it has and also be interested in problems that it is having. Can't hurt.

lsxs13

There is an RPM sticker on the old trans but no ID numbers to reference and they can't go by VIN#'s.

jonjoy

06 and 07 trans are not the same, how do I know? my 06 had a pin break inside it, dealer did not want to rebuild it, so they got a new 07 from GM and I was told it was an upgrade over the 06, I believe they have different model #'s

playtoy

Yes. Mine looks just like a base rear end. When I blew apart my rear end, RPM built me a z06 and you can tell the difference. A least I can't.