Author Topic: Tremac T-56 conversion  (Read 8618 times)

Offline 79SilveradoK30

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Tremac T-56 conversion
« on: September 22, 2002, 04:46:00 PM »
Well, I've run into a problem. My stock Turbo 400 doesn't have enough gear for good gas mileage in my '79 1-ton. I considered a Dual Range Turbo 400, one with 3 standard gears and 3 overdrive gears, but the cost is about $2000 or more. So, I've considered installing a Tremac T-56 6-speed manual in my truck. The drivetrain is a small-block Chevy (a 400 currently), with a NP 203 full-time 4WD transfer case, and Dana axles front and rear. Can you think of any problems I may have?


Offline RSBAD454

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Re: Tremac T-56 conversion
« Reply #1 on: September 24, 2002, 09:43:00 AM »
hello you have a big ole dually, you will never get gas mileage no matter what tranny you have. for one it has a carb, two it weighs a ton.maybe your engine is wore out, buy a new 502 replacement crate motor for like 3000 there is your problem solved with torque. you dont want all those gears for towing heavy loads and i doubt that tranny can handle it. you need to see the money you will blow on no improvement or buy an new crate 502 truck replacement motor and be much happier.

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Offline 79SilveradoK30

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Re: Tremac T-56 conversion
« Reply #2 on: September 24, 2002, 03:46:00 PM »
1. It's not a dually, it's a fleetside, long-box, regular cab 1-ton.
2. Even when the engine was new, it only got about 11 mpg.

The transmission simply doesn't have enough gear, even with the single 0.70:1 overdrive gear.


Offline 79SilveradoK30

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Re: Tremac T-56 conversion
« Reply #3 on: September 24, 2002, 04:00:00 PM »
And another thing, if 6-speeds are no good for towing, why does the new Silverado 2500HD and 3500 come with an optional ZF 6-speed manual transmission?


Offline RSBAD454

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Re: Tremac T-56 conversion
« Reply #4 on: September 24, 2002, 05:07:00 PM »
uuuuummm probably cause its a whole different tranny? you cant put a car tranny in a truck and expect it to last, plus its geared wrong. im telling you that youd be much happier getting the 502 for more torque along with the stout TH400 tanny. too much work to drop a manual tranny as well as money.  

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Offline 79SilveradoK30

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Re: Tremac T-56 conversion
« Reply #5 on: September 24, 2002, 09:28:00 PM »
1. It's cheaper to find a T-56 out of an F-car in a junkyard than to buy a dual range TH-400, besides, I know a place that seels parts cheap.

2. As I recall, the Turbo Hydramatic was designed for cars, was it not? So all of our Turbo 350s, Turbo 400s, Turbo 700s, and so on, are all really beefed-up car transmissions. Why can't I beef-up a T-56 6-speed?

3. Tremac T-56s live behind the brutal Dodge Viper (yes, I had to talk about a Dodge, I'm sorry), those make 450 bhp and 500 lb-ft for a '96 and up GTS.

4. Geared wrong, how? These are the gear ratio specs for a TH-400 and a Tremac/Borg Warner T-56:

GM TH-400
1st - 2.48
2nd - 1.48
3rd - 1.00

Tremac/Borg Warner T-56
1st - 2.66-3.36
2nd - 1.78-2.07
3rd - 1.30-1.35
4th - 1.00
5th - 0.74-0.84
6th - 0.50-0.62

Not only does the T-56 have better gearing, but the advantage of three extra gears, two of them overdrive gears, reducing the overall rpm at cruising speed, which increases gas mileage.

One last thing for now: Big-blocks are good, but big-blocks aren't everything.

Now, if you're not gonna help me with the installation of a Tremac T-56 into my truck, just stop talking, OK?


Offline RSBAD454

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Re: Tremac T-56 conversion
« Reply #6 on: September 25, 2002, 09:32:00 AM »
well whatever man, your old 79 with a 454 will not get an improvement in gas mileage. if it was fuel injected and computer controlled then maybe. your 454 wasnt designed for a truck either, look back and see that it came out in a chevelle and corvette, to be honest big blocks are hot rod motors. the motor does the pulling not the tranny homie, the tranny transmits the power. true the 6 speed has lower gears' but they are designed for speed. your not wanting to listen to reason so go get your 6 speed manual and spend the money where you dont need it. and yes the big block is everything, that 502 with your setup now will run circles around your low torque 454.

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Offline 79SilveradoK30

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Re: Tremac T-56 conversion
« Reply #7 on: September 25, 2002, 03:41:00 PM »
Umm...where did you hear my truck has a 454? I don't know where the heck you got that, since it's powered by an LF4 400 cid small-block Chevy.


Offline RSBAD454

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Re: Tremac T-56 conversion
« Reply #8 on: September 26, 2002, 08:48:00 AM »
oh well excuse me, didnt know 1 tons in 79 offered a 400 small block? i have never seen one with out a 454. well anyways theres your problem! 400's definitely arent pullers. well do what yah want i was just offering some advise and suggestions.

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chevymark

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« Reply #9 on: September 27, 2002, 06:03:00 PM »
You say your .7 overdrive isn't enough, th400 do not have an OD, a th700r4 does.  First thing I would do is a least get a np205 or 208 transfer case, the full time 203 will kill gas milage.  If you want a tranny, a NV4500 would be best, but you still have to convert to a manual, which isn't hard as long as you have the parts from another truck.  A t-56 is plenty strong(rated at 450ft-lb torque), but the gearing is performance oriented, plus the shifter will sit too far back and expect to pay at least $2000 when all is done(assuming you use a good used tranny).  You also need to make mods to make it fit a truck which means more $$$, and good luck finding one without paying some money.  A built 700r4 will take anything you would through at it, plus it is an auto so it is naturally a torque multiplier(torque converter).  Just get a lockup converter if you get one.

RSBAD454, the 400 sb has plenty of torque, it will put a 350 to shame.  The 400 is the best puller there is if you want gas milage.


Offline 79SilveradoK30

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Re: Tremac T-56 conversion
« Reply #10 on: September 30, 2002, 01:37:00 PM »
I know TH-400s don't come with overdrive, but the first owner of the truck had it added in along with the Dana axles front and rear.


Eric 85k10

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400
« Reply #11 on: September 30, 2002, 04:24:00 PM »
I agree with chevymark
RSBAD454 not to be rude but I dont think you are paying attention to what you are talking about.
502 big block isn't the answer to all power problems and the 400 is a torquey engine.. stock with 180 hp and 380hp, and with some good small block upgrades it will be alot more.

If you want to keep an auto, get a th700r4, its a good auto for trucks. And you should definetly get an np205, that should be first on your list, the fulltime 203 should really be bad on your mileage, especialy if you do alot towing and driving around. Also is your K30 running 4.10 gears?


Offline RSBAD454

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say what?
« Reply #12 on: October 02, 2002, 09:52:00 AM »
first off the 502 will pull that 400 backwards......hhmmmmm lest see 515 lbs ft of torque compared to 300 something? yeah i think i am paying attention to what im talking about, whatever that comment meant? 700R4 trannies arent meant for pulling heavy loads, yeah they are great for highway cruising to lower the engine RPM and maybe some street rod action but thats about it. i was just saying that for more grunt the 502 would be the cheapest route. sorry if there is no agreement but thats what forums are for to express opinions right? im just giving suggestions that i think would be benificial for certain applications. peace out..............

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Offline ChevyGuy

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my opinion
« Reply #13 on: October 04, 2002, 12:17:00 AM »
Look in a Jegs book or a Summit and they sell the newer th400's that the overdrive. These trannies came in the 90 model pickups and they were electric but the company i think Jet made them to work without it and they only cost probally like $1200 i think. As for more gas milage do motor upgrades like a MSD box and little things to improve gas milage and horsepower that 400 has the torque and power to pull anything. It has a longer stroke and bigger bore if i remember right. And if you go to a bigger motor you might as well bought a new truck or dug yourself a hole for all the money you are goin to spend on gas. I got my 76 1/2 to get better gas milage by putting a automatic which i choosed the th400 and i have a 350 thats .060 that i did little improvments and got the gas milage up to 12 or 13 with 3.40 gears. with 2.73 i got like 16mpg. Also gearing plays a factor with gas milage. Its your truck no one can tell you what to do to it. Just do what you think is right on right information that you recieve and not lame hot rodding information. Not everyone wants to be a hot rodder and poor.


Offline RSBAD454

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opinion
« Reply #14 on: October 04, 2002, 08:08:00 AM »
which tranny the 4L80E? i believe this is the tranny offered for the Th400 OD. if that is the tranny i think they are like $2,200.

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