darrensls1formula

I have been part of many A4 vs M6 debates between the three F-body sites I am a member of and one of the biggest arguments I always got from M6 guys was how much fun they are and how strong they are (compared to the 4l60e).

I myself have decided to put a lot of money in my car. I'm getting LT headers, 224/224 114 lsa cam, ported heads, suspension upgrades and a 125 dry shot of N20. I figure around 400 rwhp NA and 500 rwhp on the spray. So now I decided to do a tranny swap first. I was debating between going with a T56 manual or a TH400 so I used the search button and researched.

WOW! I saw a bunch of guys stating that they are dumping the T56 for a th400. This is a popular drag racing setup with big stall torque converters so that did not surprise me. What did surprise me was how most of them were under 500 rwhp and claimed to have gone through 3 or more T56's before coming to the decision to swap for a TH400. I thought the T56 could handle 600 rwhp easily? Should I do the T56 swap or would I be better off going straight to a TH400?

Any input is greatly appreciated

blue2000Z28

Alright, the T-56 can hold some power. The TH400 can hold more. More people are ditching 6-speeds because autos have constant ET's and a 6-speed really doesnt. The 600rwhp question. I dont think so. I am no expert, but i think that 500 with no minor upgrades is ok. But with MINOR upgrades you can get about 550?? I dont know that much but im sure there will be more experets in here is a little while

BigBronco

iTrader: (2)

most of the guys that have swapped out to Th400's from T56s spend ALOT of time on the track, and usually have other daily driver cars. If that is the case, then it makes sense to just swap out to the automatic and call it a day.

I'm still running a stock T56 in my car and it is holding up fine on a 400+ rwhp cam car with a 175 dry shot.

-xaon

darrensls1formula

That's awesome because I want to go with the T56 but all the posts on multiple rebuilds and ditching it for a TH400 was making me hesitate.

NHRATA01

iTrader: (10)

I think alot of the guys who go through T56's on a regular basis are the ones out there racing about once a week, powershifting and beating the heck out of it and have the car pretty much a dedicated track car. If you're like me and go to the strip about 5 times a year, you'll probably be alright with it for awhile. The T56 is a pretty tough trans (though not without some defective units) but the bottom line is things like the synchros are wear items, and powershifting 10 times a week wears them pretty darn fast.

In 3.5 years, 35k miles and probably 100+ passes, my T56 hasn't had a burp yet.

EDIT: BTW if you think T56's are weak, talk to the 5.0 guys and ask them about the "Rent a T5 program". People lunch those regularly with 250whp.

67Firebird455

iTrader: (27)

Yeah, those trannies are TRASH. I was gonna go with a T-56 in my 67 firebird, but dynoing at 676 hp @ 6200 rpm, and over 600lbs torque above 4500 rpm on 91 octane, running slicks, calvert racing mono leafs, caltracs, and the ability to pull the front wheels like nothing made me rethink that... I didn't want to trash an expensive transmission or continually throw driveshafts/u-joints/rear yokes. I ended up buying a "bulletproof" TH400 with reverse manual valve body, no trans brake, I leave off an idle, 3800 continental stall and haven't had any problems yet!. Race weight is 2955 + my 220lb ***. Both transmissions are awesome, but it has a lot to do with how you drive it or beat on it...

Slart

if you want to make a t-56 strong, just remove the gearset and give g-force a call. They've got some wicked setups.

I'm thinking about it now for my 800rwhp mustang (just trashed a tremec tko), but including the transmission and conversion parts it'd be over $4000. I'm drooling, but dont have that kinda money to spend.

2000WhiteTA

6 speed's are good transmissions but they still have some problems. There are many people on this site that are running 9's with 6 speed transmissions. You just have to know you are going to break stuff sometimes and there is nothing you can do about it. Taner on this site runs 9.44 @146 with a 6 speed so they will hold some serious power.

Camaroholic

iTrader: (1)

They can hold the power, but I recommend you learn how to rebuild / refresh them yourself. That's saved me a bunch of time and money. Yeah, little things can go wrong with them too... but I like bangin' the gears at the track.

jmd

iTrader: (4)

Regularly, the synchros have problems. The gears hardly ever have problems on the T56. I'm happy g-force has found their niche as a successful business, I just don't see the need, or the unbridled enthusiasm to replace what ain't broke.

They tout the T5 buildup as some wonderful thing. Yet, just like the M22 gearset, the real problem was in the case (of the M21,) just as it is in the T5.

Straight cut gears all you want, when the case moves around, you'll have problems.

Slart

Good point.

The reason my paradigm is different is I just broke a gear in a tremec tko, so my thoughts are focused on finding a tranny that wont do that again.

You know, g-force sells a triple cone synchro conversion too

jmd

iTrader: (4)

Yes, but what happened to the gear? Did the synchro teeth get hurt, did a gear tooth get chipped, did a gear tooth get broken off, etc.? You're vague. Vagueness is bad.

Slart

In my case I broke a tooth off th3 3rd driven gear (not the cluster).

NBM2001z28

iTrader: (43)

I think a lot of the failing is driving error, i say that because i basically have a headers car and have no third gear at all right now. I missed 3rd 3 times under a power shift and the gear is **** now. i havent taken it out and looked at it but ever since i missed that last time its definately been a hit or miss if the car would go into gear even with just regular street driving. I'd say with 350rwhp i ruined it for sure. I doubt it was the trans too. I was only on a 245 nitto hitting 12.02's and its been done for this year for like 2 months now.

Slowhawk

iTrader: (12)

I've had very good luck with all of my T56's.Got 200+ passes out of the TA and been powershifting my Vette without problems. The biggest problem I see with people trashing T56's is the clutch.It has to fully disengage when shifting to save the syncro's.