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When my FSJ was stock and there was no vacuum to the Tcase, I had to circle around to synchronize and engage the Tcase. Now, I am installing a 2001 Magnum power train into my 1989 GW. Will my 231D w/o vacuum have the same synchro issues going into 4wd? Or is there a fix for the 321D Tcase?

Papa George wrote: ↑Thu Jan 14, 2021 10:20 am When my FSJ was stock and there was no vacuum to the Tcase, I had to circle around to synchronize and engage the Tcase. Now, I am installing a 2001 Magnum power train into my 1989 GW. Will my 231D w/o vacuum have the same synchro issues going into 4wd? Or is there a fix for the 321D Tcase?

I moved this thread to Modified FSJ Tech, as its not a build thread.

As for your question, typically going into 4wd high does not require driving in a circle, or going forwards or backwards. You can shift in 4wd high while driving down the road without any issues.

Shifting into 4wd LOW however is best done with the vehicle rolling slowly and shifting the transmission into neutral. Then it should go in and out ok. Sometimes rolling in reverse works better.

An NP231 will act is a very similar manner to an NP229 from a shifting perspective. Although the 231 does not have a full-time 4wd mode like the 229 does. Also, it is possible your 229 had some sort of issue with it caused by wear that made it hard to shift.