So I finally cooked my nwc t5 and now I'm looking for a replacement for my 86. I have a 357 with400 hp. So I found what I think to be a good deal on a 3550 tremec, it has 25,000 on her wince the rebuild and is now rated for 425 torque, but I've heard of these handling 500+ stock so I'm not worried about that. I just want to hear if anyone has put one of these in their car and how they liked it. I have 3.42's in my rear and the ratios on the tranny are 1st 3.27
2nd 1.98
3rd 1.34
4th 1
5th 0.68
rev 3
I don't really know if these are good ratios or not. Any help would be great. And btw I know a few people are just going to say to get a tko 600, but this trans is only going to cost me 700 versus 2300.

 

I have the TKO500, which is essentially a stronger version of the 3550. The gear ratios are a bit far apart between 1st/2nd, so its a bit like the 700-R4 in that regard. The shifts arent quite as smooth as a T5, so it has a somewhat ratchety feel. But otherwise, its like any other manual and works fine.

You will need some kit to install it:
-Different bellhousing or adapter plate to allow the trans to bolt up.
-Retrofit pilot bearing (http://www.summitracing.com/parts/LAK-15975/)
-Relocated torque-arm mount and retrofit xmember, or new torque arm/xmember (ie spohn unit)
-Retrofit yoke or new driveshaft with C4 trans style yoke
-Mechancal speedo adapter
-Possibly a different shifter as the trans sits straight up, rather than at an angle like the T5

Fortes, 5speedtransmissions, or other sites can hook you up with what you need to get it in.

The only real issue I had was that the trans is larger than the T5, and needs to be lowered to clear the floor pan (the aftermarket spohn xmember will locate it where it needs to be). The net result is that there is roughly a 7-10 degree difference between the driveshaft CL and trans CL since the rear of the trans is lower than the T5. It seems to cause some minor vibration issues at high speeds on the highway.

 

Additionally, you may want to also invest in a dial gauge and some other equipment to check the centricity and parallelism to be sure theyre within spec. The aftermarket bellhousings are not as precise as the stock unit. The trans allows for a maximum deflection of ~.015" at the tip of the input shaft, which gives a tolerance of .005" for the location of the centerline and .005" out of parallel for plane of the trans with respect to the flywheel. If the bellhousing does not locate the trans within those specs, then you can have issues with poor shifting, clutch disengagement, or premature failure of the input shaft bearings.

Tremec has a users manual for the TKO that goes over a lot of this in detail. Many web sites also go over how to perform these procedures.

 

Yeah I bought the relocating bracket and mechanical speedo a while back at a swap meet so luckily I have that and I was planning on running my t-5 bellhousing with the adapter so hopefully I won't have the centricity problem (I'll double check with a gauge anyways) but I definitely don't want vibrations at high speeds. Would you recommend changing my driveshaft or just the yoke? Will either one fix the vibrations? And high speeds as in 100-120 or 120-160? Lol

 

If you use the adapter from McLeod, make sure you double check the fit. On mine, I had to clearance out the area on the adapter plate around the bolts for the front bearing retainer so it would clear. If you dont do this, the trans will be all kinds of misaligned when you bolt it up. The adapter plate also has .003" of clearance at each point where the trans and bellhousing bolt up, so you may need to reposition it a few times until its centered. As long as you torque the bolts to spec, itll stay put. You can double-check everything by bolting up the trans without the clutch. The input shaft should easily slide into the pilot bearing with no binding once the BH is engaged with the dowel pins on the back of the engine.

The vibrations are mainly an issue when going above 90+ MPH, but are not too severe. Its more of a nuisance. There is some leeway in the driveshaft angles, so you can probably get it close by shimming the trans mount and adjusting the rear if you have an adjustable torque arm. I had no trouble with the pinion angle, but at the trans, I ran out of room and could only get it to within 10 degrees or so.

 

As for the DS, I think the yoke is still available, but it may be better to just get a new TKO-retrofit DS from Spohn or someone else. The Spohn unit comes with bigger u-joints and yoke, and also is a larger diameter so its stronger than the stock one. I have one (actually the first unit they made, if I recall), and its held up well. But, when I got it, I had to use the stock C4 yoke from spicer as the larger aftermarket yoke was not in production yet. It also requires a special u-joint that is hard to find if my memory serves me correctly.