TH350 rebuild tech
(Minor clean up.) |
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==Variations of the T-350 family== | ==Variations of the T-350 family== | ||
| − | There was also a T-350C | + | There was also a T-350C and T-250C version that has a lockup torque converter (TCC). Look for the end of the input shaft to have a smooth polished end with O-ring on it. The case has a "C" cast into it, and there will be an electrical plug adjacent to the shifter shaft on the driver side of the tranny. |
Don't confuse the TH350C with a TH350 non-lockup tranny with a screwed-in electrical connector on the ''passenger'' side of the case. This is a pressure switch that was used ~1972-'73 for the Transmission Controlled Spark (TCS) system. This disabled the distributor vacuum advance in all gears except high gear, and is a single wire switch threaded into a pressure port near where the cooler lines are located. In the case of this switch, you can either leave it in place, unused- or remove it and plug the port. | Don't confuse the TH350C with a TH350 non-lockup tranny with a screwed-in electrical connector on the ''passenger'' side of the case. This is a pressure switch that was used ~1972-'73 for the Transmission Controlled Spark (TCS) system. This disabled the distributor vacuum advance in all gears except high gear, and is a single wire switch threaded into a pressure port near where the cooler lines are located. In the case of this switch, you can either leave it in place, unused- or remove it and plug the port. | ||
| − | Only the larger | + | Only the larger ransmission/converter companies build high stall torque converters for the T-350C because of the low demand for them. |
The T-250C has a band adjuster stud and locknut on the passenger side of the case near the cooler lines. It looks much like a T350 other than the adjuster (same physical size, same pan shape). | The T-250C has a band adjuster stud and locknut on the passenger side of the case near the cooler lines. It looks much like a T350 other than the adjuster (same physical size, same pan shape). | ||
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Photo shows accumulator cover, spring and piston (snap ring not shown). This is located on right side of trans case. Check the bore in the case for scratches or other damage if the spring was found broken. | Photo shows accumulator cover, spring and piston (snap ring not shown). This is located on right side of trans case. Check the bore in the case for scratches or other damage if the spring was found broken. | ||
| − | [[file:T-350_acumilator01.jpg|frame|none| | + | [[file:T-350_acumilator01.jpg|frame|none|Accumulator cover, spring and piston with sealing rings.]] |
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*Front port (blue) is third gear pressure. | *Front port (blue) is third gear pressure. | ||
| − | [[file:T-350_acumilator02.jpg|frame|none| | + | [[file:T-350_acumilator02.jpg|frame|none|Pressure ports circled.]] |
=Transmission reassembly= | =Transmission reassembly= | ||
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Then install the return spring and retainer using the tool pictured. | Then install the return spring and retainer using the tool pictured. | ||
| − | [[file:TH350lowspringtool.jpg|frame|none| Tool used to compress the springs | + | [[file:TH350lowspringtool.jpg|frame|none|Tool used to compress the springs and retainer to install the retaining snap ring.]] |
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To prevent excessive end play, a pump thrust washer can be installed on top of the input planet, then the regular thrust washer. Then install the small outside snap ring to hold it all in place. | To prevent excessive end play, a pump thrust washer can be installed on top of the input planet, then the regular thrust washer. Then install the small outside snap ring to hold it all in place. | ||
Check the output shaft for proper rotation, there will be some drag, especially in one direction. | Check the output shaft for proper rotation, there will be some drag, especially in one direction. | ||
| − | Check for excessive output end play. If end play is excessive, it can be tightened up by | + | Check for excessive output end play. If end play is excessive, it can be tightened up by disassembling and shimming up the output ring gear bearing from the case. |
Now you drop the input ring gear on, spinning into place. | Now you drop the input ring gear on, spinning into place. | ||
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Even firmer shifts can be accomplished with check ball removal and modifications to the accumulators. It is recommend to NOT modify the 1-2 accumulator. Retain the cushion spring and do not block the circuit. The 2-3 accumulator can be blocked by several methods. | Even firmer shifts can be accomplished with check ball removal and modifications to the accumulators. It is recommend to NOT modify the 1-2 accumulator. Retain the cushion spring and do not block the circuit. The 2-3 accumulator can be blocked by several methods. | ||
| − | Removing the 2-3 accumulator spring and using a spacer (nut, washers, cut down section of tubing) between the piston and the E-clip is the "shade tree | + | Removing the 2-3 accumulator spring and using a spacer (nut, washers, cut down section of tubing) between the piston and the E-clip is the "shade tree" method. You can also block the feed in the valve body to the 2-3 accumulator. |
Installing the direct piston will require some patience, a lip seal installed or 0.010" feeler gauge, and a trick to use is a section of plastic cut from a 3 liter soda bottle to use as an outside installer tool. Set it in the drum, and it will force the lip seal into the drum without using a tool around the entire circumference. You may however need to work the exposed part of the seal into the drum with the feeler gauge or seal tool. | Installing the direct piston will require some patience, a lip seal installed or 0.010" feeler gauge, and a trick to use is a section of plastic cut from a 3 liter soda bottle to use as an outside installer tool. Set it in the drum, and it will force the lip seal into the drum without using a tool around the entire circumference. You may however need to work the exposed part of the seal into the drum with the feeler gauge or seal tool. | ||
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