MASTER REBUILD KIT ON SPICER 18 TRANSFER CASE

With all of the t-case disassembled it needs to be thoroughly cleaned and all parts need to be inspected for excessive wear or damage. The case needs to be checked for any cracks (they may be hairline so it helps to use a magnifying glass if one is available) , should the case be cracked it is best to replace instead of trying to repair it. Inspect all of the components to determine any that may be in need of replacement. As visible in our pictures here we had excessive wear to our Output Shaft Gear as well as our Output Shaft Sliding Gear so we will be calling on the guys at Novak to get us the gears we will need to make sure this Spicer goes back together with not only replacement gears, but the best we can get our hands on from a trusted company. 

Before cleaning the case and the rear bearing cap we had a couple of races and seals to remove that we will be replacing with new as well.

With all of the parts cleaned and separated we set them off to the side, separated the parts that we needed to get replacements for including the Speedometer Gear Drive and got the replacement parts ordered and on the way so we could get this Spicer put back together and back in our old Willys.  

With the arrival of the new parts it’s time to get the Spicer back together so we can get ready for the trip coming up in just a few short weeks. The reassembly is pretty much the reverse of the disassembly. You will want to pay close attention to the recommendations of the supplier of your rebuild kit (Novak has some great advice included in their instruction sheets on what to expect and what to look out for). The front output cap gasket thickness is a factor in the end-play adjustment of the rear output shaft. The front cap must be reassembled and installed on the case along with both shift shafts and forks. If the shift fork retaining screws were drilled for safety wire, be sure to rewire.

We placed the front bearing cup into the case knowing it will be adjusted when we put the rest of the gears and both front and rear output caps on and set the end play. Next we put the gears on the output shaft, put them through the case slid on the output thrust washer (tangs go in slots on output shaft). The snap ring will go on next as well as the front bearing; you will have to work the snap ring up the output shaft gradually as you go. Once the snap ring is locked in place I put some lithium grease on the bearings so they will have some lube for any movement during the reassembly process, next I put the rear bearing cap in place and temporarily put the rear bearing cap on to hold the bearing in place while I installed the front bearing cap.

Before I could put the front bearing cap back into place I needed to essentially rebuild it with the new parts supplied by Novak including the oil seals as well as the new bearings for the Output clutch Shaft. The Pilot bushing took a little bit of effort and a little cursing to get out (thankfully we didn’t have to throw any tools or tantrums to finally get it out). We pressed off the old bearing, pressed on the new, swapped the seals and began the install of the front bearing cap (don’t forget the gasket that goes between the case and the front cap).

When you put the front cap on it has to go over the shift shafts, in doing so you want to be very careful not to tear the seals. If you take a very thin feeler gauge you can assist the shafts as they go through the seals to help prevent any damage. Also; don’t forget the bullet shaped interlock pin that floats between the shift rods. Install the front cap in place and tighten.

Hold the rear output cap on the rear bearing and measure the gap between the cap and the case with a feeler gauge. Add .010 to the gap thickness to obtain the thickness of the shim pack for the initial setting.  

With a dial indicator attached to the case and the contact tip against the rear of the output shaft you need to pull and push the output shaft to get the reading of the end play. (Factory spec for end play is .004 to .008 but a better job results if you maintain .002 to .006) This is EXTREMELY IMPORTANT and must be measured with a dial indicator and not by feel or by eyeballing. It took us a couple of times mixing and matching the shims to get a reading of .003 so we felt comfortable with that. Once the proper thickness for the shim pack has been established, remove the rear cap and shims and apply a thin coat of RTV silicone sealer to each shim in the pack. Reassemble; torque the bolts to 30 ft. lbs. and recheck the endplay, which should still be in the recommended range of .002 to .006.

Next we were ready to put the Poppet Balls and springs back in the case (Novak supplies new springs with their master kit). With that finished we installed the new, felt out put shaft seals and reinstalled the front and rear yokes, also using new cotter pins in our castle nuts.

Next to go back together is the intermediate shaft, if you use a little bit of grease on the thrust washers they will stay in position inside the case while you are putting the intermediate gears, shaft, cage bearings into place. (Remember, the intermediate shaft is slightly tapered so it must be installed from the rear of the case as to not damage the case or the shaft).  

With the thrust washers in place the intermediate shaft and gear can go into place (Don’t forget the o-rings on the intermediate shaft). It is best to lube or grease the cage bearings before you put the assembly together, use a light coating of gear oil and insert the cage bearings into the intermediate gear and hold in place in the t-case as you slide the intermediate shaft through the gear and into place. Lock the intermediate shaft down with the bolt and retainer plate.

Once that is back together you want to make sure the Spicer works in all ranges so it should be put into all positions of the case and check to make sure it all works properly. If so go ahead and put the new gasket on and tighten down so it will be ready to reinstall on the vehicle.

If you want to paint it now is a good time to do so. The reinstall is reverse of the removal shown earlier in this project.

Special Thanks: NOVAK Conversions for their donations to this project and for their help along the way!! Glade Meredith for his assistance as well and the use of time and space for a big part of this project!