Tko600 Warning!!!!

[Fordfan69]

Hi guys,

I have measured the gears both new ones now pre-assembled in box, and old failed ones. The measurements are as follows:

3rd gear driven gear width: .975"
3rd countershaft gear width: 1.010"

The difference being: .035" (insignificant, in my opinion)

Mis-alignment from 3rd gear to 3rd countershaft gear: .140"

This equates to 14.4% of the total width (SIGNIFICANT, in my opinion)

This means (as you surmised) 650 ft./lbs. - 14.4% = 556 ft./lbs. capacity.

This is a reduction in strength of just about 100 ft./lbs..

My 450 ft./lbs. at the wheels + heavy car + very soft street drag tires = probably over the capacity of the available 556 ft./lbs. of capacity at the tranny.

I really think this theory is correct. Has anyone had the opportunity to check their tko600 yet? I would bet many if not all with the single countershaft are the same.

Greg.

[eschaider]

The pictures fooled me. I measured the countershaft gear at 23.5mm wide (0.925")in the photo and the mainshaft gear at 28mm wide(1.10").

If we use your measurements and assume the wider gear was the correct design width then the .975" wide gear has only .835" of face width in contact with its mating gear. The transmission's torque capacity in third gear would then be (0.835/1.01)*600 or 496 lbs-ft.

I used 600 lbs-ft as the transmission torque capacity because that is what Tremec advertises on their website http://www.tremec.com/English/products/TKO.asp

If you have the tires hooked up and an engine with approximately that much torque and then add the rotating inertia of the engine-flywheel-clutch assembly at say a 6000 RPM shift point, it is not hard to see how you could induce a cascading third gear tooth failure that would get both the driving and driven gears.

I believe that even though you have good replacement parts you will desroy them yet again if you engage third gear under power with the tires hooked up. The gears need to mate up without misalignment and should be the same width. Look at all the other gear pairs, that is the way third should look.

This is minimally a manufacturing QA problem if the wrong parts got put together. If these are the right parts then we have a much bigger problem for all of us and also Tremec.

Ed

[hssss]

No tech and I have only plowed thru the first third of this thread but couldn't help but compare this thread and one that I recently saw over at c-c. http://forums.corner-carvers.com/showthread.php?t=31831

[keislerNick]

Originally Posted by Fordfan69

My 450 ft./lbs. at the wheels + heavy car + very soft street drag tires = probably over the capacity of the available 556 ft./lbs. of capacity at the tranny.

Greg.

If you decide to sell your transmission and go to something new. I would consider the transmission from the toyota supra. I have personally owned 2 of them and it will hold up to what you have easily bone stock. The getrag v160 transmission is a 6 speed and there are tons of supras still running this trans stock because no one has upgrades for them and you never hear about issues with them. I have seen alot of guys talk about the weight of your car and the torque. Ryans supra has a stock trans in it weighed 3550 on the scales and has run 8.62@171 in the quarter mile with 1350whp to the ground and has not broke the trans yet. This tranny is a good one if you are considering a stock unit that will more than do the job for your car.