T56 Magnum / TKO 600 / 18 spline A833 Passon OD 4 speed

Finally decided to put a stick shift OD in my ‘67 Barracuda that’s a 383/727/4.11/3000# car that I use primary as a daily driver. Been kicking it around for a while & the cost just makes it un-appealing but I just went ahead & sold my ‘72 SWB to fund the swap.

Back around ‘01 I swapped a 833 for a Keisler TKO 500 5 speed in my ‘70 Barracuda & it worked out great but there are lots more choices these days & it was a stock 360. I really am shooting for a set-up to handle the drag strip & shooting for low 12’s/high 11’s.

I’m really wanting to run a mechanical clutch instead of hyd. for simplicity but the T56 Magnum is only available with the hyd. set-up.

What’s the experience you guys have had with banging gears in the newer transmissions vs the rebuilt A833.

Any advice/tips/stuff to watch out for?

My only experience with any of the newer overdrives has been with the tko600. I say that if you are going to put slicks or even drag radials on at the track, stay away from the tko. I know there have been many others who have been/are successfully racing them in their cars, but i broke 3rd gear 3 times. 1st timw with drag radials. 2nd and 3rd times with slicks. And the 3rd time was after having Liberty faceplate the gears. Broke on the first run after that. However, i am much heavier at 3,900 lbs.

I do use the tranny for street/hwy driving and absolutely love it. It is perfect for that. If you absolutely have to run that, i would think about getting an adjustable slipper clutch that you can dial in some slip to lessen the shock load on the tranny. These clutches are not really optimal for a true street car that gets driven heavily. This is just my experience for what it’s worth and in no way am i bashing the tko. I do believe it is a stout tranny and has its place. Just not on the track in my car anymore.

By the way, the breakage was done with my old motor that ran 11:40s. Not my current motor

I’ve been researching all the options for od as well for my satellite. I’ve decided on the T-56 magnum. It can handle 700 ft lbs of torque. Yes there is fabrication involved but my car is a 318 car and I can’t keep waiting for a passon 5 speed. With your 411’s and the double OD of the T-56, I feel that’s a perfect combo.

I'm old school. I put a Doug Nash 5 speed in my car 30 years ago so I was probably one of the first guys to have a 5 speed in a Mopar. The Doug Nash whines and shifts like a tractor but it has held together all of this time. I like having the extra gear and I have no intention of ever going back to a four speed but I would prefer a more modern transmission. My next move will most likely be to a T56. I don't really need the double OD but I think the T56 is the best option on the market these days for a manual trans that will handle a lot of power.

The other possible option is to look at some of the aftermarket five speeds. There are some folks who are building semi-custom boxes that have serious torque ratings.

I just finished drag week with a T56 Magnum behind a 392 Hemi in my 31 Plymouth Coupe. This is my first experience with the T56 Magnum. I was holding off on reporting my opinion because I have not as of yet thoroughly evaluated it. But since the topic came up I will let you know my findings so far. With the clutch out idling in neutral and the car stopped, the transmission makes a lot of noise. The noise doesn't bother me, but it makes me wonder if something is wrong. I've heard from others on the web that they are known for being noisy under these circumstances. On the street the transmission is awesome! It shifts nice. The gear spreads are great.
But if you're going to use 6th gear, you better have deep gears or a Torquey engine! I have 4.57 gears in the rear end, 30 inch tires, and at 70 miles per hour in 6th Gear the engine is turning 2200 RPM. This engine has a huge cam, and barely runs at 2000 RPM, so I never used 6th unless I was going 75 mph+.
I also had trouble trying to power shift at 7000, it would hang up. If I lifted off the gas, it shifted reliably, and reasonably quick. But this could be clutch related. My soft lock clutch has an iron disc, which is heavier than an organic or Kevlar disc. Plus counter weight on the levers which can hinder high RPM release. So before I can really make a call on the power shift ability, I need to work on the clutch more.
I hope this info helps.

years ago I used to race a 70 340 dart 4-speed, and loved it. The main issue with most of the newer units is that they use a pin and rail system to shift the forks. Manual transmissions have a interlock system so you can not engage two gears at once, because severe damage can occur. The pin and rail system makes it hard to speed shift the gears. They used to modify the pins and rails to make it easier, but I could never shift them as fast as the old mopar A-833 Put a Tremec 5 speed in a while back and paid extra money to have it modified for better shifting and could not tell much difference.

T56 so long as you are ok with cutting the floor pan and torsion bar crossmember. Significant sugary is required. Doesn't bother me but some guys don't want to touch an unmolested floor.

Based on the 3 options, no doubt I'd go t56. It is the most work also though as mentioned, takes some cutting. I wouldn't mind having one of Passons 5 speeds for my belvedere, but I lack the patience to wait for one.

I have a viper t56 in my B.B. duster for 7-8 years. It’s great. I really like having overdrive. Between that swap and when I put the 700r4 in my Jeep wagoner I found I was driving them much more.
I didn’t buy a kit, a guy or 2 did the t56 on bigblockdart forum. I wanted overdrive, at the time a used t56 and QuickTime bell seemed like the cheapest possible overdrive option.
The 2 overdrives seems useless to me. Maybe it works good in a modern oem efi vehicle but it doesn’t seem to be necessary with an old B.B. I’m running 3.73 with a 25.5” tire. I can go with more gear but it seems like 1st gear would be useless then. Maybe it’s me or where I live but I’m not really cruising faster than 75mph.

I saw that g force modified mustang trans in one of the magazines recently, 5 speed with a 1,000hp rating that seems really interesting. Looks smaller too. I would consider that next time. Mph and speed are close to hemijoel, I have to be doing 70 to use 6th. My engine will still pull at 1500rpm but you can just feel it wants to be at 2,000 under that kind of load.
If the gforce will fit with minimal floor mods it seems like a winner. I just haven’t seen anyone running one in a Mopar.

I'm waiting on the buzz from the field on the GForce remade 3650 5 speed, and with its size, and $4650? down stroke.

Last issue of Hot Rod had the write up.

I did a 394Ci G3 Hemi for a guy who has a Gforce 3650 trans in a 98 Dakota, he's hurt the 9 inch rear twice but the Gforce3650 is going strong. truck has run as fast as 10.10 @ Island and Maple grove went 9.90a truck weighs in @ 3700 race weight. the 3650 can take some punishment with the GForce set up also Pro-Force out of Lawrenceville Ga builds a respectable 3650 trans.

that being said, I think the T-56 /6060 is you best bet.

I run the TKO 600 behind a warm 496 in a Challenger. It runs on the street and some road track (HSAX). I love it on the street. Driven hard on the track the 2-3 shift is a little tender.

I went with the .81 OD which is a top speed gear with my setup (3.23 rear, ~25" tires, 243@.050" 108 LSA cam). The engine could eaisly carry more overdrive when cruising... double overdrive would be handy in my setup.

On last freshen my engine made 687 ft lb on the dyno so I am pushing the TKO pretty hard.

If I upgrade it will be a T56.

For what it's worth, I have no noticeable noise at idle, but I do get a decent rattle under heavy load, which is amplified by the long pistol grip handle.

I've done plenty of 6000rpm no-lift-shifts [ECU cuts spark/fuel] with no issues.

6th gear use depends on the gear set, I have the close ratio T56 with the 0.63 6th [not the 0.50] and 6th is very functional for me.

There's a thread with lots of pics on FABO by a guy who just did it. "Some cutting" is an understatement
It came out great in the end, but he also included a price list. Cost about $6000 AND he did a huge amount of surgery.

Meanwhile, although it may take a long time to get one, the Passon A855 is $5500 and bolts right in

I have a Richmond 5-speed I built for racing and I currently run an 833 street HEMI 4-speed for just street driving. I have built a few overdrive 18 spline boxes with Jamie Passon's overdrive gear sets and they turned out good. I think you are smart to want mechanical or external clutch operation. I would HATE to have a hydraulic release bearing fail because you need to disassemble everything to replace it.

I have been inside a few Viper T56 transmissions they seem plenty strong enough but they are not known for their power shifting.

I like the Richmond for the 3.27 low gear and 1-1 final drive that way you can run a 3.23 gear in the diff for good road manners at 70 MPH.

Just make sure you spend some time with your fabrication the first time and make sure your driveline angles are correct.

Gus

Meanwhile I built my car in the amount of time some people have been on the waiting list for a Passion, and I can guarantee service parts will be around, if I ever need them.

I haven’t really been driving my duster much, just took it on a 4 hour ride and refreshed some things I probably forgot. At 80mph I’m at 1900rpm. 6th works fine with my combo down to about 15-1600. It will still pull a good hill too. I’m running a mild 400bb with a first gen ez efi, 8.8 with 3.73s and approx 25.5” tires. Mine is a stick viper trans, i won’t say it’s silent but I can’t complain. I still think a 5 speed with a .75 is would be nice. The more radical the engine I think the less useable the double of will be. An old school engine with a big giant cam and isn’t going to work as well as a modern engine with factory efi.

Were you trying to say you DID build your car, or will have built it... actually I don't care. I'll be driving mine with the A833 anyway

...did.

I never said it takes a little cutting I already have all the parts to do the same swap into my cuda and I'm no where near 6k, maybe half that. I went with a low mileage viper t56, new quicktime bell, mcleod twin disc, billet flywheel, etc... not junk parts. My belvedere was a 4 door converted to a 2 door, last thing that would bother me is cutting out the tunnel.

I'm not waiting 5 years for a transmission.... that whole thing is a mess on those 5 speeds. If you could pick up the phone, order one and have it in a week, that would change everything, but 5500 is far more than I get put a t56 in a car for.

That $6k did include a $3k T56 Magnum and a few other parts like a bellhousing, driveshaft, clutch disc with the proper splines... see the price list on the thread which lists absolutely everything he bought

I'm impressed that you can get all that stuff for a total of $3k though.

https://www.forabodiesonly.com/mopar/threads/t56-magnum-conversion.416558/

I agree that the waiting list has been ridiculous. Jamie Passon could sell a lot more transmissions if he can actually produce them in reasonable numbers.

I just parted with an '02 TransAm that was set up as a street/strip car. The car had a 9" with a 4.33 gear. With just a cammed LS1 it ran consistent 12.0s at 116mph with a T56 Magnum and a Spec clutch. I will tell you that to get the best shifts out of these, the investment in a Tick hydraulic cylinder kit is the only way to go. Prior to having one, trying to shift hard full throttle above 6200rpm or so was impossible. The clutch would either hang up or you would be locked out of gear. After the Tick MC upgrade, the clutch would disengage cleanly as high as i cared to rev it (usually around 6700 or so.)
As far as comparable shifting, I previously owned a 1970 Mach 1 with a Toploader, and have driven a Challenger with a 833. The toploader was the easiest to shift hard with the 833 being just slightly a bit more notchy. That being sad, BOTH are still easier than any T56 I've driven and I've been in 5 different cars with them in it.
As far as gearing with the extra overdrive, I ran 28" tires with a 4.33 gear. If given a chance to do it over again, I would've run AT LEAST a 4.56 to fine tune the trap rpm a bit better and still wouldve been putting along on the highway in 6th.

If you're going to drive the car alot, the T56 Mag is a great tranny but it's huge and expensive and needs a little work to make a crisp shifting machine.