I think this is the best place to ask about a problem regarding my t56. It’s in an 86 cutlass with a 406. I was told the trans was from a 93 Camaro. When the trans was out I would spin the input shaft (while in any gear) it would spin easy then get to a point where it was difficult to spin, it would get past this point and get easy again. The hard point is for about 45 degrees of rotation. What could cause and is it a problem?

 

Most likely a bad bearing or a damaged shaft. It could even be a damaged gear itself.

FYI depending on which version of the 93 T56 you have it is either weak or really weak. You should think twice about putting it behind a torque monster like a 406.

93 F-body with (M28) 6 speed Torque rating 360 lbs-ft. Has 2.73's - GU2
1st: 3.36
2nd: 2.07
3rd: 1.35
4th: 1.00
5th: 0.80
6th: 0.62

93 F-body with (M29) 6 speed Torque rating 400 lbs-ft. Has 3.23's - GU5
1st: 2.97
2nd: 2.07
3rd: 1.43
4th: 1.00
5th: 0.80
6th: 0.62

 

wow, unaware of this till now. I previously had this trans installed and dragged it with 5k clutch dumps with 525 lbs of torque. What makes this trans weaker than other t56? Can this trans be built by prominent companies such as wick to hold more torque, or is there an inherent design flaw? I will take it easy until I get this built or replaced.

 

You can call a company like wich but I think the issue is the case itself, The higher the first gear ratio in them the more stress there is between the input shaft and the counter shafts. These two shafts try to pull a part, If they flex the case far enough the gears will work like a saw and cut each other up. Once GM went to the LS3 they had to use the heavier version of the T56.

FYI the 94-97 T56s are rated at 450 lbs-ft of torque. They have a shorter first gear, GM put 3:42s in the rear to make up for it.

Also keep in mind this are factory ratings that would need to make it out of warranty and the stress on the trans is not greater then the ability of the car to hook up. Meaning if you are running street tires on a stock type suspension your ok but if you are running slick with a 4 link suspension that is adjusted correctly she will have a much shorter life.

 

very concise response, thanks for this information. I use pretty tall M/t drag radials so I will weigh my options.