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Can I use a shim under the center support instead of at the case to tighten up endplay?

The reason I ask is I currently have a TH350 pump bearing and a .010 shim and my endplay is at .021.

I also have a .030 shim that fits under the center support thrust race and with this shim installed my endplay is .005 is it ok to shim it here?
 

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NO. That is not even playing a role in determining the rear end play. Next time you setup the rear end play , leave the reaction carrier on the bench and you will understand.


Hutch
 

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It would be nice if some how this stuff could be hostd so the fotos could be used.I have tried unsuccessfully.Can anyone tackle it?Someone offered to do so if I sent jpeg but can not figure out how. Anyway here it is without fotos / schematics.



There are two clearances that need to be checked and adjusted when assembling the rear section of the TH400 transmission. There is rear section end play and reaction carrier (666) end play.
Rear section end play is the operating clearance of the rotating parts between the center support (654) rear thrust surface “A” and the transmission case rear thrust surface.
Reaction carrier end play is the floating clearance of the reaction carrier between the thrust washer (656), installed in the center support (654) rear thrust surface “B” and the thrust washer (674), installed in the output carrier (675) front thrust surface. Because the reaction carrier floats between the rear of the center support and the front of the output carrier), it does not affect the rear section end play. Because the output carrier is attached to the outside diameter of the output shaft flange (692), it does not affect the rear section end play. When checking and adjusting rear section end play, we will assemble and install the rear section of the transmission into the transmission case WITHOUT the output or reaction carriers. Reaction carrier end play will be checked and adjusted following the checking and adjusting of the rear section.
During the preparation of the transmission case, the case bushing (33) was replaced. The bushing was installed to a specific depth to act as a register for an upgraded one piece thrust bearing assembly and selective shims to replace the output shaft to case thrust washer (695) and the output shaft to case selective thrust washer (696). Install the one piece thrust bearing assembly into the case and over the register, seating it against the rear thrust surface of the transmission case. See Figure.




We will now assemble and install the necessary components into the transmission case to get our initial rear end play numbers. Before continuing I would like to mention something that may get your attention when you start to understand the rear section end play components. Although we are installing the main shaft (681), and sun gear shaft (664), THEY DO NOT AFFECT REAR END PLAY. They are only being installed at this time keep the thrust bearing assemblies in position during end play checks.
Identify the chamfered end of the sun gear (665). Install the sun gear (665) down over the main shaft, chamfered edge down. See Figure. Install the sun gear shaft (664) down over the main shaft and into engagement with the sun gear. See Figure.


Install the thrust bearing to sun gear race (662), flat side down, over the sun gear shaft and against the front face of the gear. Install the needle thrust bearing (661) on top of the race. See Figure.
Install the assembly into the transmission case. See Figure.


Install the center support to case anti fretting ring (657) into the case. Align the ring end gap with the intermediate band anchor pin in the case. See Figure.
Install the thrust bearing to center support race (660), flat side up, into the recess in the rear of the center support (654). See Figure. See Figure.


Install the center support into the transmission case.

Install the center support to case beveled retaining ring (645) into the case groove, with the beveled side facing up. Align the ring end gap with the intermediate band anchor pin in the case. See Figure


The rotating components of the rear section, from the front face of the sun gear to the rear face of the output shaft, operate between the 3 piece thrust bearing on the rear thrust surface of the stationary center support and the one piece thrust bearing on the inside thrust surface of transmission case. The distance between the center support and transmission case thrust surface remains constant, except for thermal expansion and transmission case flexing. Therefore rear section endplay is the operating clearance between the rotating components and the 2 thrust surfaces. See cut away view in Figure.



In general each bearing assembly can run with close .002” clearance. This allows for the oil film on the bearing surfaces as well as for thermal expansion. Because there is a total of 4 thrust bearing assemblies used in the rear section, operational end play should be between .008” to .012”. Install feeler gages between the output shaft rear thrust surface and the output shaft to case thrust bearing assembly to obtain your rear section end play value. See Figure. Remember, the transmission case has been sectioned for the reader to better understand the procedure. It is not as easy to insert the feeler gages when the transmission case has not been sectioned. There is a window in the case right above the governor tube holes in the case. This is where you will install the feeler gages. See Figure



Adjusting clearance value is accomplished thru installation of selective shims behind the case thrust surface and the thrust bearing assembly. Available thicknesses of the shims are .010, .015, .020, and .025.
 
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