I had so much fun with my SL55 this summer, possibly too much fun. I did pretty hard pulls from 0-60 mph few days ago, had lots of fun again, parked it. Few days later, I slowly drive out of the neighborhood and then give it 75% throttle on main road and all of a sudden, seems like I am not in a gear. I look at the door dash, and I am in a gear. I realize my tranny is slipping. I couldn't really get it up to speed as anything more than 20% throttle would just raise the rpm's and would not gain more speed. If I did it slowly, it would not shift to the next gear, and once I reached 5k or little more of rmp's and speed, i would release the throttle and while slowing down, I could hear some slight winning noise
I limped to the closest parking and I check engine light lit up. I attempted to drive again, but it would slip right away, meaning I would be in "D" but car would just spin the rpm's with no power to wheels. While I was waiting for a tow truck, the transmission cooled down and it would go again to gear and drive, I even got it once to the second gear, but I was back again with same situation I was when I got out of neighborhood half hour ago. After half hour or so, the tranny cooled down and I could at least drive up on the tow truck with no issues. I took it to a local imports shop tonight. We will see how it goes. I don't know what the codes are yet, I will post more info tomorrow. I was told by the pervious owner that the car is tuned with some custom pulleys and suppose to be at 600hp or so. I never had it dyno'd so I am not sure, but maybe too much power to the stock transmission?

What you guys think? If tranny is bad, should I buy an used tranny on ebay or have the shop rebuilt it?
How about getting the manual swap? Maybe ahead of Tavarish's 3 year project, lol?

Thanks

PS, how you guys like the WB kits?

 

The shop would likely have a transmission shop do the actual rebuild. The NAG1 is a fairly common transmission and a good shop will have suggestions for upgrades based on your power levels. If you had an SL500, I would say get a salvage yard unit. There are low mileage transmissions available for a few hundred dollars. However, a tuned SL55 is a different animal and I think you will want to do some upgrades.

 

Transmission is bullet proof, only way for it to go bad is lack of maintence or "gremlins" under the hood. Either one is bad...

 

Just a quick follow up. I ended up getting a low miles user tranny from a fellow forum member. Shop swapped it for around $1600, which I though was reasonable. Works like a charm, putting those horses down again
In the mean time, when I get some time, I will see about building the one that failed for more HP
Thank you all!