Guest Fast Frog Posted March 3, 2001 Share Posted March 3, 2001 While spec'g my engine upgrade (427, 440, or whatever), I've been researching the capabilities of the WC T-5 vs the T-56. I've discovered that most tranny experts, as we all know, say the T-5 is great if you're in the 300 to 350Tq range and you don't abuse it. If you're running 400Tq or more, then just mashing the petal to the metal, particularily in 3rd, may blow the tranny up-namely 3rd gear. What is it with the 3rd gear?? Too small and fragile! Or is the tranny as a whole just too small to take that much torque. I'd love to keep my T-5 (and save some $$ too) and just bolt it back on when my engine project is completed. I don't race the car but there's still some hondahs and mustangs out there that still need spanking.I'd love to do the duty, but if 3rd gear won't hold up even to brisk acceleration then it's T56 time. BTW, I'm anticipating 500+ ft lbs of Tq when my engine project is done. Is there anyway I can save $2000+ and keep the T-5?? Rick Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted March 3, 2001 Share Posted March 3, 2001 Rick, IMHO....You're spending a Boat Load of cash to build a Rock Solid BigSBC; why would you consider skimping on the transmission? You're gonna want that 6th gear when you get on the Hwy. Besides; the fact ramains-you are not gonna drive that car easy once its in the car & that snotty nosed Honda goes Ziiiingy by you with all his Sears Robuck Body Attachments. How humilitating would it be when you attempt to catch the Honda guy just to hear a loud pop/grinding noise as your weaker 5spd imploads? There's no way anyone can spend the money you're gonna spend for that Huge Pavement Poinding, Asphalt Rip/Snortin Monster you're building and keep your foot out of it; AINT NO WAY! You got it & you're gonna use it! Another factor to think about; what if you use the weaker trans & when the trans goes out on ya from normal upshifting; what possible damage will that do to your engine if it causes you to excessively over-rev it; better incorporate a rev-limiter of some sort also. IMO: If I had the cash to build a BigSBC like you're building; I would want a rock solid transmission to go along w/it & I'ld do/spend every bit as much on it as I would on the engine; proportionately speaking of course. I know it costs more up front-but in the long run it will save. And, shifting into 6th gear & watching the RPM's fall is gonna mean less wear-n-tear on your engine at hwy cruising to boot! Stop a minute; think about all the "THOUSANDS" of additional rpms your engine will be rev'g if you chose to go w/a 5spd instead of the 6spd. As you're thinking about those additional "THOUSANDS" of rpms; remember how much you're spending on building that BigSBC. How much sooner would you like to have to build another one simply because you wore the first one out too quickly from choosing a 5spd instead of a 6spd? Okay; you brought up torque. Think about this. Figure the Driveshaft Torque w/trans in third gear. (Multiply 3rd Gear Ratio x Torque). 3rd gear is somewhere around the 1.35:1 area. With the 427 on a Dyno you're around 530ft.lbs peak torque depending on camshaft that's somewhere around 4500/5000rpm's in 3rd gear you're putting out around 675ft.lbs of torque....that's a lot of torque! All I can say is "POP" time to buy another trans! This is my theory on the 3rd gear problem in a 5spd. Rick, Say you're racing (At the 1/4 mile track) & you run your RPM's upto the 5500 range; when you shift into the next gear, say 3rd....you're RPM's will drop to about 4500 (THAT'S YOUR AREA OF PEAK TORQUE-530ft.lbs for your 427SBC) so when the Camaro's & Stangs shift into the next gear at peak torque; They're are shifting into PEAK TORQUE & Snapping the Driveline; you better have a trans that will keep up w/you! Especially if you're running a BigSBC! Just some things I'ld be thinking about if I had the cash/optioins & sorry if I rambled-but it's raining here again (no garage) & Rick had a good question; couldn't wait to jump on it! Kevin (Still an Inliner) [This message has been edited by Kevin Shasteen (edited March 03, 2001).] Quote Link to comment Share on other sites More sharing options...
DavyZ Posted March 3, 2001 Share Posted March 3, 2001 Since no one has yet posted a scientific reason behind the 3rd gear mystery/misery, I want to theorize: In first and second gears the engine vs. weight and gearing is up to great acceleration. In third, you start pushing major air. The combo of friction, weight, gearing, and torque is probably enough to tear up third gear, with the air resistance pushing it all over the edge. How's that for a theory? Now let's hope someone with facts chimes in! David Quote Link to comment Share on other sites More sharing options...
Guest zfan Posted March 4, 2001 Share Posted March 4, 2001 Rick, I myself have not had the t/5 in any of my cars but my father has and said it was a pos unless driving easy with light tork. He had roughly 425hp plus nitrous and he said no go with it especially third gear. He is not in town but I will see him next week and see if he can be more specific as he is a gear head from the word go. He was racing 57 chevy in 57, wow!!! he's an old fart. Mike Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted March 4, 2001 Share Posted March 4, 2001 I think they just have a weak link & the Mfg's know it. They are not going to do anything about it. Why should they when they can hit you up for a replacement trans or the dealers can hit you up for a rebuild? It was like GM in the early 80's w/their 440t4, 200's & 700's; remember those units-nothing but milk-toast. At lest GM finally got past those bad years & now they are pretty reliable trans. Only time will tell if the units well get stronger. Kevin (Sitll an Inliner) Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted March 4, 2001 Share Posted March 4, 2001 The normal T5 held up to my twin turbo 302 for over a year. 450HP and gobs of torque. One day I beat it hard, the next it blew 3rd upshifing in highway trafficrush hour. For a STOCK application they're fine until a kid pounds them. 3rd is vulnerable because it's a longer throw, there are no stops on the shifter, and in a fast upshift the shifter forks can bend. This is supposedly the beginning of the end but I'm sure it's not the only reason they die. It may have something to do with the number of gears on that shaft, bearings, who knows what else. I've seen plenty blown apart at my friend's shop - he tries to keep a couple around in good shape as people always seem to need them He's apparently gotten VERY good at rebuilding them using parts from others when needed and will buy a blown one if given the chance. As for the OEMs somehow knowing this and ignoring it so they can stick it to you for a new trans - uh uh. Ford went so far as to retard timing in the ECU when they could sense a shift was being done in order to kill torque to save the trans. This was in 94-95 Mustangs and the 93 Cobra ECU had whacky code in it too timing-wise. They also went to WC transmissions at some point in ALL of the cars and there were other upgrades along the line as well. Why? Warranty work! If you were a dealer you had a constant stream of tranny rebuilds and replacements coming through that you charged back to HQ - that's not cheap. Sure, when the warranty runs out the consumer is stuck and when they see the cost they're also pissed - at FORD. Neither of those is a win for Ford or GM on the Camaros either. Although I think Ford did more to beef up their T5s than GM FWIW. The transmissions are decent so long as you don't exceed their ratings or beat on them. We don't beat on our cars do we? Unlike the T56s where Borg WarnerTremec apparently learned their lesson and seemed to underate the trans, power figures for the T5s are apparently pretty close if not slightly optimistic. If you want I can ask my friend what's killing 3rd but I'll bet I know what he says - kids pounding shifts! (lol) Quote Link to comment Share on other sites More sharing options...
DavyZ Posted March 4, 2001 Share Posted March 4, 2001 Do I drive like a kid? Well, maybe...but I'm still going with a T5 'cause they are cheap relative to a T56. If I could only afford a T56 retro-fit tranny, AHHHHH!, that would be nice! Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted March 5, 2001 Share Posted March 5, 2001 Frog, From what I understand the reason why so many T5s fail is because, like Jim said, bent shift forks. The aftermarker shifters with positive stops should cure this problem. As for the third gear failure, if I remember correctly, it is because of the long main shaft in the T5 flexing under torque load. I have always been a Ford person and read a great of the Ford magazines. 5.0 Magazine had a great writeup over the summer by Bob Hanlon on rebuilding the T5 trannys. Chris Quote Link to comment Share on other sites More sharing options...
Z-Dreamer Posted March 5, 2001 Share Posted March 5, 2001 Fast Frog, I love the smooth shifts of the T5! Nothing comes close! So if you want to keep using a T5, checkout: The Gearzone at www.gearzone.net/ There is a ralley clutchless design that handles 450 FT torque. ------------------ " Now where did I set my beer? " [This message has been edited by Z-Dreamer (edited March 04, 2001).] Quote Link to comment Share on other sites More sharing options...
John Scott Posted March 5, 2001 Share Posted March 5, 2001 Frogman, What finally swayed me to go T56 was visiting our local trans shop and seeing the pile of T5 gears! I spent a lot of time discussing a WCT5 only to find that even with all the upgrades it still wouldn't handle drag strip duty. No I don't plan on really abusing my trans, but you get the adreneline up some day and really bang a couple...who wants to pull a transmission again. No matter how cheap they are. One more costly T56 is going to be cheaper than a few T5s. Your monster SBC deserves nothing less than a T56. Don't create a weak link! You'll sleep better knowing its in there. BTW my friend blew his new WCT5's third gear THE DAY it was put in. That was with a bone stock 305. JS [This message has been edited by John Scott (edited March 05, 2001).] Quote Link to comment Share on other sites More sharing options...
Guest Fast Frog Posted March 5, 2001 Share Posted March 5, 2001 Thanx Guys!! Great words of wisdom! I kinda knew the answer to this question before I posted it. But I wanted to see if someone had experience or knowledge of a way to use or beef up the trusty but light weight T-5. Well, I guess it's going to be T56 time pretty soon-hopefully later this summer. Thanx again! Quote Link to comment Share on other sites More sharing options...
Guest JAMIE T Posted March 6, 2001 Share Posted March 6, 2001 Ever seen a factory 350 Iroc with a 5 spd? NO?, thats because GM knew of the potental failures and only offered a stick in a 305 car. I had a WCT5 in my old stang and it has lasted for a long time. It is still in the car and has seen MANY pounds of BOOST. It always had a good clutch and a good aftermarket shifter. That monster of yours Frog, needs a T56 though, absulutaly the toughest trans for the money. Remember always, Drive it like you stole it! Jamie Quote Link to comment Share on other sites More sharing options...
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