Tremec 3550 or TKO?
 

I have replaced my AOD transmission with a t-5 already. Now The T-5 is giving me more problems than i care for. I've got a vortech S trim and edeelbrock aluminum heads, cobra intake, and tons of other stuff along with 4.10 gears. So i know it's probably a matter of time until i break the T-5. I have heard that the TKO has a 31 spline output shaft, and the 5th gear ratio is .83 compared to the 3550's .68 Is this true? What all would I have to replace besides the bellhousing to go 3550 or TKO? Which would you guys recommend. I'm thinking maybe TKO if the output shaft were 28 spline like the 3550 or T-5. Thanks for any help.

I just bought a Tremec 3550. I had the same questions you have. There is no difference between the tko and the 3550. The only diff is the input and output shafts everything else is the same. I called D & D performance and they told me I didn't need the tko. I have the same maybe more than you done to my car.
If you get the tko you will need a new clutch (GM type). and you have to change the yoke on your driveshaft, which comes with the tko.

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'93 LX 425rwhp/410rwtq

I'm faced with the same decision. I've busted two T-5s in the last 12 months. The 3550 costs less, but the TKO is a "once and for all" solution. Wife is nagging me for new kitchen cabinets, so it's likely to be the 3550 at this point.



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Russ L
'91 LX
Procharger, 3 row intercooler, extrude honed Cobra intake, Mac full Length Headers, 30# inj., 73mm C&L, 75mm tb, E303 cam, 289 rods, ported E7 heads, MSD, T-Rex w/255 lph Walbro, 5 lug conversion, Cobra R wheels, 3.27 gears and Moser Axles.

OK, as Forcedpower said, they are the same. Both the 3550 and TKO have .68 5th gears, and both have 28-spline output shafts. The 3550 is rated at 425 ft/lbs and the TKO is 525 ft/lbs. Other than the torque capability they are the same.

Thanks for the information guys. I pretty much knew if i went for the TKO i would need a different clutch. I had heard that the TKO had a .80 5th gear overdrive, but i wasn't sure i wanted that since i have 4.10 gears in mine and i drive it a lot. Maybe I am thinking of the D&D performance TKO plus. I think i might go for the TKO since I've replaced an aod and t-5 already. I'm getting tired of going through transmissions like they are chocolate chip cookies.