Transfer Case torque specs

[Tim7750]

I'm getting ready to reseal my transfer case and was hoping someone could clue me in on the torque specs fpr the flange nuts? I've never been into a transfer case before, so any pointers would be welcomed.

[MSeriesRebuild]

I'm getting ready to reseal my transfer case and was hoping someone could clue me in on the torque specs fpr the flange nuts? I've never been into a transfer case before, so any pointers would be welcomed.

The torque spec for the flange nuts I believe is 110-120 ft. lbs. I can check at the shop tomorrow to see just how well my memory is serving me on that.

The main issue with leaks at the seals is this. The original seals were poor quality at best, so they are a leaking issue. A much more likely finding when you pull it down may be rust pits on the yoke seal mating surfaces. The felt pre-seal in the originals holds water like a magnet does steel, causing these rust pits. Installing new seals, no matter how good their quality will not stop oil leaking around a pitted surface. The pits must be repaired in addition to installing a quality seal to stop the leak. A simple redi-sleeve will fix the problem if it isn't too severe. We have turned down a few that were severely grooved to accept a repair sleeve, then brought the surface back to its original diameter. As long as all the issues are addressed during the procedure, you should turn out a good end product for a reasonable cost. The seals needed are National #410308, redi-sleeve #99212. The same pitting issue is likely on the shift shafts, it is not possible to use a ready sleeve in that application, thus replacements of the shafts are necessary if pitting is present. We use custom machined stainless steel shafts as replacements, this puts a stop to the pitting issue for good as stainless does not rust. Good luck.

[cuz]

Hello Tim,
The 8031-2 calls out 140 to 160 Ft Lbs for all the companion flange nuts on the transfer case.

[MSeriesRebuild]

I'm getting ready to reseal my transfer case and was hoping someone could clue me in on the torque specs fpr the flange nuts? I've never been into a transfer case before, so any pointers would be welcomed.

I checked my chart we have posted near our building bench today. We pull the companion flange nuts to 150 ft.lbs. The 3/8" bolts that hold the rear drive units in get 34 ft.lbs., the bolts that secure the e-brake drum to the flange get 38 Ft.lbs. We use grade 8 fasteners in these positions. The fill/check and drain plugs are pulled to 25 ft.lbs. All bolts and plugs in through holes get high-temp thread sealer applied or oil will weep around the threads over a few days. The inner surface of the flat washers under the flange nuts get a good bead of silicone applied, this will push in around the splined shaft eliminating oil from leaking down the splines. All this is common practice on all our rebuilt t/cases, we have found it works very well.

Oil recommendation is 50 weight synthetic transmission oil, these cases tend to run on the warm side, this type of oil will help that issue significantly. We use Synergen from www.synergenracing.com, Rowland Johnson is our contact person.

We are about to get a test underway using 40 weight Royal Purple oil in a NP200 case with an auxilary oil reservoir, an oil cooler, and a pump system, total oil capacity is 7.5 qts instead of the 2.5 qts as original. Have instrumentation in place to monitor the results, I'll likely do a detailed post on it after testing is completed.