I have recently purchased a 2001 C5 base model and wondering what transmission it’s born with, are they any good maintenance procedures to undertake, or should I send it in to a transmission shop and get the fluid flushed out, it has 70,000 miles on it

 

Just drop the pan, drain the fluid, change the filter, re-fill. Don't flush. I did my '99 at the dealer before I sold it, big improvement after, cost was about $350.

 

If your car is an auto it was born with a 4L60-E

 

Unless you are having issues with the transmission, just follow the recommended maintenance schedule outlined in the owner’s manual.

However, if you are uncertain how the car has been maintained, it won’t hurt to go ahead and change the fluid just to have a baseline going forward.

 

Toys for Life C5 just posted a pretty good video on the procedure. It might help you decide between DIY and going to a shop.
https://www.corvetteforum.com/forums...fluid-vid.html

 

I had a mechanic tell me NOT to change it. It has 99K on it and the manual says change at 100K. What do you think?

 

Change your fluid. If you can’t change it yourself safely, any mechanic shop can do a drain and fill, or drop the pan and change filter. C5’s have been out for almost 30 years, it’s not rocket science anymore. Midas muffler worked on my c5 for years. My Dad ran the shop, and his good mechanics worked on the car, sometimes after hours, so all I had to do was buy parts and give the guys some cash. I have a Quickjack now and have been wrenching myself. I haven’t tackled the trans yet.

 

I'd change it. There's a thought that by changing it your loosening the gunk which will cause problems. Manual even says to do it at 100K, Were it mine it would be changed.

 

This advice is based on *usually* much higher mileage transmissions that have never been serviced. The idea is the friction material worn off of the clutches is suspended in the old fluid and if you drain that fluid out and put fresh fluid in then your clutches may slip as they are worn out and the fluid is no longer helping them grip. I have yet to actually experience this in real life despite being told about it by many people and I am the type to at minimum drain and fill on any auto transmission I own.

I don't know that I would trust much advice from a mechanic recommending against a service on a sub-100k mile transmission.

 

If a mechanic told you not to change your engine oil, would you listen to them ? It's a fluid that gets contaminated with moisture, particles from the friction discs and breaks down from heat.
Think of it not only as a lubricant but a preservative. I change it at least as often as the GM recommendation, sooner if you have a heavy foot. Cheap insurance against having to buy a new one or rebuild the current one.

 

Manufacturers recommendations for service are BS, especially when it comes to trans services. They say 100K, so it will be out of warranty and then when it starts to fail, they can sell you a new car. I serviced my 2024 10R80 at 5K miles which included a 2000 mile road trip last summer. I added a deep sump pan at the same time, to get rid of that STUPID plastic oil pan a lot of makers are going to. I will service it again at 30K and every 30K after. After a week of drag racing the truck daily and driving it now for a year with 17K miles on it, shifts like butter with no weird habits. With the vette, mine had 56K miles on it when I bought it, it got a fresh trans service right after I got it home.

The example on oil changes is a good one, look at what GM is finding out, not only are the service intervals too long in between, but the viscosity they originally recommended seems to be an accomplice in the issue with the 6.2's and it bearing design.

Like others have said, if a mechanic tells you servicing is a waste, find a new mechanic. It is not a hard job to do, just takes some time and the ability to lift the car.

I watched this video this weekend regarding manufacturers recommendations for servicing and the issues with a lot of trans missions and their designs. This guy was a factory tech and then went off on his own to fix problems the big makers just don't care about. It's a little long, but it was a great discussion.
About half way through they discuss valve bodies and the issues with the current designs since the early 2000's. Pretty good stuff IMO. They talk about more than just the 10 speeds.