Thursday, April 26, 2012

After a long laps in time finishing up trade school and moving on to Penn State to further education (and to experience college life) we finally got time to focus on the quadra-trac transfercase. Nobody said it was going to be easy. With dwindling availability and lack of demand for this case it literally took 3 transfer cases to make 1 good one. Borg-Warner 1339 is the model number. They came with and without the low range reduction unit. Ours has the reduction unit as all CJ's came with them. It was an option on the full size Jeeps. The problem area is the differential unit, which includes spider gears and
cone clutches. The damage to these units occurs when automatic transmission fluid is used instead of the required quadra-trac fluid, which is a must if these are going to survive. The cone clutches will get destroyed along with the shaft that holds the spider gears. These cone clutches were never available separately from Jeep. The complete differential was, and had to be replaced as a unit. A torque bias test can be performed to determine if the clutches are ok. If the transfercase is out of the vehicle, and by making sure the emergency drive is not engaged, then hold the input yoke with a breaker bar and socket and a torque wrench with socket on the
output yoke and apply torque in a clockwise direction, the clutches should break loose between 80 and 170 foot-pounds. If it releases below 80 then the unit will likely need replacing, on the other hand if it requires more than 170 then improper lubrication might be the culprit. The other problem area is the chain. It will eventually stretch to the point that it will jump teeth on the differential and drive sprockets. Not good. Tension on these chains can be checked through a chain inspection plug. There is a chain tension tool (J-25162) for this purpose, but I have not been able to locate one, even by asking dealers. Guess they were thrown out long ago. So I fabricated my own using a male air hose quick disconnect fitting with a male pipe thread on the opposite end a 20 penny nail and a wing nut welded to the point end of the nail. These chains were originally made by Morse but have recently been manufactured by China for Crown. If you read the jeep forums, reviews on these chains are not favorable with failure occurring sooner than later, ending up breaking and then
damaging the case in the process. I was able to find 2 new Morse chains from 2 different suppliers, Northfield 4x4 in Lehhighton, Pa. 610-377-3992 of which I bought his last NOS one and the other from Walcks 4 Wheel Drive in Bowmanstown, Pa. 610-852-3110 of which they had several and said they could get more no problem that Morse might be remaking these chains. They also have the gasket kits and bearings or Quadratec part number 52208.01 or from 4 Wheel Drive Hardware part number J8125030. We started by disassembling the cases and finding all the good usable parts and luckily found a good usable differential with good clutches. Did a good cleaning and inspection of all the bearings and associated parts. The bearings for some reason rarely go bad, which is a good thing because they are not cheap. The differential unit we used checked out good with the clutches releasing at 145 foot pounds. I won't go into assembly procedures here, there are alot of good manuals and online info for that. JP Magazine also did a couple of articles on rebuilding one. We did spring for a new rear output bearing for the transmission, part number 6308nr from Bearings, Belts & Chains, Inc. for $37.47 This bearing has the snap ring groove. One thing you have to watch is different speedometer drive gears if you are building from different cases. Other cases use an offset housing that compensates for the different gear diameters, on these cases you have to match up the proper drive gear with the corresponding driven gear. We chose to mount the transmission and transfercase first then mount the engine. This way we could man handle each component and support the front of the tranny off the frame and hook up the driveshafts.


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