I have an 87 split transfer case on my H55f tranny. It will not stay locked in low. I have to use a strap to hold it over. Is this a big or small problem? Thanks.

P.S. I tried a search but did not find any threads.

If it is due to the shift linkage or a bad motor mount allowing the engine and tranny to rotate during acceleration and hit the linkage against the bady, then it is a minor problem to fix.
If it is due to excess wear on the dog clutch splines and their corresponding teeth on the hi/lo gears, then this is major to fix.

Motor and tranny mounts are new and should not be a problem. Linkage--maybe, I'll check it out.