Flat towing a 4x4

[landy]

I want to tow my '72 Blazer with a tow bar for 200 miles or so. It's got a manual trans, NP 205, and locking hubs. Ok to do with hubs unlocked, trans and transfer case in neutral, or should I remove rear driveshaft, too?

Thanks!

[Bigdav160]

I've heard it recommend to lock the hubs while flat towing. This will rotate the gearset in the NP205 to keep it lubricated.

Unfortunately rotating just the rear output shaft does not do this.

[landy]

Hmm, doing a Google search gives conflicting info. Some say the NP205 can't be flat towed and others say no problem. Guess I should just disconnect the rear driveshaft to be safe.

[Yukon Jack]

I can't think of any reason why you would have a problem leaving the vehicle in neutral. Sure the rear driveshaft will spin but that isn't going to create problems with the NP205. I wouldn't lock the front hubs either. If you're really worried, throw the tranny and the transfer case both in neutral. If this was an automatic transmission vehicle, you'd have different concerns.

[Bigdav160]

Modern transfer cases have a lubrication pump connected to the output shaft. The internals get lubricated anytime the rear driveshaft is turning.

The NP205 gets it's lubrication by the gear splashing in oil. (orange)

Flat towing in neutral will be turning the items (pink) that are completely out of the oil.

Locking the hubs will turn the front output shaft which should provide some splash lubrication. (blue)

You could pull the driveshaft to be safe.

[landy]

Great visual aide! I'll disconnect the rear driveshaft and tie it up just to be safe.

[Yukon Jack]

That explains it really well - this site continually educates me.

[Redcap]

Pull the driveshaft.

[argonaut]

Agreed. Unlock front hubs. Pull rear driveshaft. Should only take about 15 minutes with a wrench.

[swamp rat]

Bookmarked!