novaderrik

getting towards the tail end of gathering the parts to put a T5 in place of the 700r4 in my 86 Camaro.. i got a trans, bellhousing, flywheel, and clutch hydraulics from an 84 Z28, and the engine i have is a 355 with an unknown cam that seems to be a lot like the Edelbrock Performer RPM cam (measured around .490 and .510 lift on my dial indicator), which should put me in the area of 400 hp and 400tq once i get the vortecs on it... the trans itself had been sitting in the car in a junkyard since '96 if the license plate was to be believed, and the fluid was nice and red. there appears to be now weird play in the trans, and it shifts nicely on my floor..

the car has a 3.42 locker rear out of an '02 Z/28 convertible, so it will probably either hook up or fry both tires off the line..

so how long will it hold together: and if the 355 doesn't blow it up, how long will it last behind the 5.3 with LS6 heads and LS9 cam that i'm looking at putting in the car this winter? everyone says the NWC trans is junk, but one of my cousins just could not kill the one that he had in an 83 Z that he pounded the crap out of for the better part of a year... i don't dump the clutch at every stop sign, but i also like to row thru the gears fairly aggressively from time to time...

sofakingdom

iTrader: (1)

Transmissions always have "play" when de-installed. The drive shaft yoke is what support the rear of the mainshaft; without that, the whole thing just flops around aimlessly inside.

The way that transmission will fail, is by the case stretching across the front. This is the first in an irreversible cascade of events. It is caused by the force of holding the clutch gear and countergear meshing, which when under load, they try to spread apart from each other. Since there's simply not enough material in the case casting to prevent this, eventually the metal stretches. When this happens, 2 forms of death immediately begin to occur: (1) the gears are allowed to mis-align, which ches them up; and (2) the fluid leaks out around the front countergear bearing, since it has no seal. When the fluid leaks out, the transmission eats itself alive from running dry, especially the mis-aligned interface between the clutch gear & countergear.

Here's what a failed one looks like from outside, in the top pic. (bottom pic is a 2nd design T-5) Note the stain below the countergear bearing from the fluid that leaked out, showing that the case is stretched and the hole is no longer round; and in fact in this one, the bearing spun in the case, because the drive fit became so loose as a result. If memory serves, this one would leak just sitting still, and if I filled it up and hit the highway, within just acoupla hundred miles the back bumper would get covered with gear lube. You can see the witness mark on the bearing (looks like a "ring" about 3/8" wide all the way around) where it's been rubbing up against the back of the clutch gear bearing retainer.



To repair this syndrome requires an unstretched case, a new clutch gear and countergear, a "kit" (consisting of all the bearings, thrust washers, selective-fit snap rings, seals, and other misc small parts); and whatever else might have got chewed up by all the metal chips in the fluid, and whatever else was simply damaged from running dry. It can be pretty heinous inside a transmission that has died this way. IOW, you need A WHOLE OTHER undamaged transmission; at which point, what sense does it even make to "repair" the trashed one. Might as well spare yourself the trouble of tearing down 2, assembling one, and THEN throwing away a bunch of wasted stuff; instead, just throw away the trashed one and install the less-failed one. Then of course the same thing will happen to it. Lather, rinse, repeat as necessary, as it WILL be.

Best advice I can give you, is to avoid any form of abuse to the transmission as much as possible. It will last indefinitely if you drive it like granny coming home from church. (which of course that's why we build up our cars, right? is so that our reward is that we must then drive like grandma? ) It will fail RAPIDLY if you abuse it, and even more rapidly if you run ATF (red) in it, no matter what you think the "spec" for the fluid happens to be. Clutch dumps and/or speed-shifting, which create shock loads, are the hardest on it, but just applying high torque overloads the case metal. If your car hooks up, it may turn to shrapnel the very first run. Sticky tires must be avoided.

I also recommend starting your hunt for a LT1 T-56 and all the parts & pieces to swap it RIGHT NOW, so that your car isn't down for so long when that "egg" fails.

midias

Could be 5k miles or 50k there a lot of guys here running T5s behind 350s with no issue and others that kill them with a stock 305.

Don't miss 3rd, use street tires and you will probably have no issues for a long time. A decent shifter also helps.

novaderrik

T56 is not an option: too heavy, to bulky, too expensive. i'd buy a brand new Super T10 and live without overdrive before going that route. i'd love a full road race Jericho, but money is a thing that i don't have enough of for that..

i'm just curious how long this thing will hold together. i've beat the ever loving crap out of other "weak" transmissions without a failure in the past: a Saginaw 4 speed behind a healthy 355 in my cousin's Monza took 3 years of abuse without dying, but i blew a very similar Saginaw literally to pieces by simply letting the clutch out nicely in my 76 Monte Carlo behind an extremely tame 350... never played with a T5, tho, so this is new ground for me..

midias

A lot depends on the condition of the case but stay away from sticky tires and get a decent shifter and it should be good to go.

novaderrik

i'm going to make the stock shifter into a short throw shifter (move the pivot point up an inch or so, and make a 1" or so spacer to raise the mounting base up... working as a machinist has it's benefits) and make some positive stops to limit travel just like the good aftermarket shifters, except everything is free and it will look stock when it's finally in the car..

superccs

Mine has survived so far for 6 years behind my 350 with the occasional drift mode being engaged. Keep to all seasons and try not to dump the clutch and you should be ok.