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4L60E Transmission Rebuild Page 13 of 29

 
Figure 49
Figure 49

Figure 49. A major flub happend here when pressing the new shaft in. The inside hub support uner the bottom of the drum was not centered, and when the shaft bottomed out, it slipped and cracked the drum. There was no way to fix it, and a second drum had to be purchased. The support problem was remedied by purchasing two 3 inch round bars 3 inches long from McMaster-Carr to use as press blocks, and they were set under it for support while pressing the shaft in. Once the shaft is in, then the reinforcement sleeve can be installed in the drum and then it is ready for final assembly.

Figure 50
Figure 50

Figure 50. The forward sprag assembly was also heavily worn, just like the input drum. It is unusable and must be replaced.

Figure 51
Figure 51

Figure 51. Pictured is the new Heavy Duty Forward Sprag assembly. It can only be purchased as an assembled unit. It is pricey, but it comes with a new one way sprag bearing already in it.

Figure 52
Figure 52

This is the assembled and finished input drum assembly. This thing was a major headache. When it was rebuilt the first time, every part except the forward clutch housing was replaced. That was a mistake. When it was tested, one piston would not close, and the cause turned out to be the small check valve in the forward housing was stuck open. A new housing was acquired from Monster Transmission and the drum was built again. It worked that time.

Sadly, pictures of the drum assembly were not taken, but will be detailed in this page. The first part is to install on the inner shaft the o-ring. The next part to install is the 3-4 apply pistion. lube the bore, input drum inner shaft, and the seals on the apply piston and use a .010 feeler gauge to roll the seals in then push the piston in.

The 3-4 clutch apply plate with the 5 fingers goes in next, then the larger diameter spring cage. Install the forward clutch piston in the forward clutch housing, again using the .010 feeler gauge to roll the seal edges in without damaging them. Insall the forward clutch housing/piston in the input drum, again using the feeler gauge to carefully roll the seal edges in. Install the second spring cage and retaining snap ring. The bottom half of the input drum is now finished.


 
 
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