Tremec 3550 question

hoopty5.0

mechanicus terribilis
15 Year Member
Dec 14, 2010
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SW Houston
Hi,

So Im going to buy the following for $1400 this weekend - its used, from a local forum:

Tremec 3550 w/ 26 spline input
Bell housing
Centerforce dual friction clutch, press. plate and flywheel
Tri-ax shifter
Aluminum driveshaft.

I drove the car it was in today before I bought it to make sure it was all in good order and seemed to be fine.

With the 26 spline input shaft, what will this trans hold? Stock rating is 425 lb ft, but I couldn't find anything else to gauge what it will hold.

Since Im expecting 475-500 lb ft from my 408, should I upgrade the tailshaft too so it would be like a TKO?

Thanks,
Collin
 
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it should be a 26 spline input and 31 spline output already. you have an original "tko" there.

rated for 425 tq with those options. a tr3550 is a 10 spline input shaft and 28 output. rated 375 torque. when you get into the tko500/600, there is more internal modifications making it stronger.

it is not just the input/output shafts that are different. you can give tremec a call with the dog tag number. the number will start tr3550 space.. then a number.

that number there will tell tremec what you have. that number you have should be a lower digit. the "tko" i almost bought which was advertised and looked like a tko600, was not. ie; the input output shaft count. people try to pull that **** all the time and they are original tko's.

tremec rep told me a true tko500+ number starts at like 6 or 7 after the tr3550. goes up to 12 for all the models.
 
transc.jpg

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Yep, its a tko: PN 2600708. I got the tko, tri-ax and new ram clutch for $950. Not a bad day...
 

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good deal. just be happy you didn't buy a "tko600".

i educated myself real well after having, not 1, not 2, not 5, but 6 people try and sell me that trans as a tko600. finally found a real one on number 7. :mad:
 
Just make sure you use the right lubricant (GM Syncromesh Black) and don't let it run low on lubricant. If you do that and don't do dumb things like shifting without the clutch, the transmission is nearly bulletproof. It will take lots of full throttle shifting and never complain.

My Tremec 3550 has been one of the best Mustang investments so far. It is on the second Mustang after the first one got totaled by a hit and run driver. Shifts smooth and fast, no problems.
 
Just make sure you use the right lubricant (GM Syncromesh Black) and don't let it run low on lubricant. If you do that and don't do dumb things like shifting without the clutch, the transmission is nearly bulletproof. It will take lots of full throttle shifting and never complain.

My Tremec 3550 has been one of the best Mustang investments so far. It is on the second Mustang after the first one got totaled by a hit and run driver. Shifts smooth and fast, no problems.

Thanks for the info! Ill go get the GM Syncromesh to put in it.

Im also picking up a SFI bell housing for a $100 today. Almost there!
 
just a heads up, i was told the pennzoil syncromesh is the same stuff for those trans. it's like half the price and you don't have to go to the gm dealer for it.

i pay around $7/quart for it at oriellys.
 
I broke my 3550 3 times from powershifting.

Every case is different: power levels when you shift, driving styles and manufacturing tolerances inside the transmission have a lot to do with durability. My mostly stock 5.0 engine may not match the power level of whatever it is that you have. Hence the reason why mine has been unbreakable so far.
 
MANY companies make Syncromesh tranny fluid now. When I put my TKO500 in this car I think I will use Amsoil brand.

Just make sure you use the right lubricant (GM Syncromesh Black) and don't let it run low on lubricant. If you do that and don't do dumb things like shifting without the clutch, the transmission is nearly bulletproof. It will take lots of full throttle shifting and never complain.

My Tremec 3550 has been one of the best Mustang investments so far. It is on the second Mustang after the first one got totaled by a hit and run driver. Shifts smooth and fast, no problems.

Yes the T5 is weak. The Tremec transmissions are "notchy" to shift but they shift so much better, especially at high throttle. I usually don't use a clutch when I shift on gentle acceleration, but a couple years of driving semi's taught me to do that, you can't even feel the shift. Pull it out at 2200rpm and put it in the next gear at 1650. I would never do it at heavy throttle! That's where powershifting comes into play! As of right now, both of my vehicles are automatics.... the AOD sucks monkey balls, the 4L65E on the other hand is the only auto I have ever liked.
 
Well, I've put 762rwhp through mine a few times and it seems to be holding together just fine. Although, I think I need some new synchros or something, because it's becoming a bitch to shift. When I get done building the rear-end, I'm going to see if I can break somewhere around 1000rwhp at full boost. I'll keep ya posted.
 
What's on it for tires though? If its not catching any traction its hard to break drivetrain parts. Mine was 275/60 dr and 28x10s when it would break. Had street tires at first and had no issues.