Differential Warning signs (1 Viewer)

[Jbone]

Hey All,

In the past year I have been in a few situations that required me to do minor/non-aggressive recoveries in reverse. I know this is extremely hard on diffs and I was wondering if anyone could give me a heads up as to what to look out for aside from the standard whining/growling. I have never been inside one so they are still just an intimidating and expensive magic pumpkin to me...
There have been no bad signs/sounds/feels so far, so maybe I am still lucky? Just trying to stay proactive!

Cheers

 

[Pin_Head]

Differentials are slightly weaker when operating in reverse, but if you broke a few teeth, you would know it. The cruiser 9.5 inch ring and pinion are tough, so you aren't likely to ever break one.

 

[Corbet]

You should be able to perform the described "minor non aggressive" recoveries all day long without worry.

 

[Jbone]

Thanks for input guys! Encouraging. There are just enough (reverse) diff explosion stories out there to have me thinking they can't handle anything in reverse. Guess I forgot to take into account the land cruiser factor!

 

[Pin_Head]

Not with Landcruisers. Don't forget that the front differentials on FJ40s and FJ60s are the same as the rear and the front one drives on the "reverse" side of the gear teeth and you never hear of them failing.

 

[Jbone]

Do the 40's and 60's have a high pinion as well? Does this contribute at all to the reverse "weakness" in any way?

 

[Pin_Head]

No, the front diff on 40s and 60s is the same as the rear with a 9.5 inch ring gear. When driving forward, it is the weak direction.

The front high pinion on 80s is also "reverse cut" which means that the normal forward operation is in the strong direction for the teeth. The reverse direction on 80s is the weak direction and you hear of the front failing on 80s. The ring gear is only 8 inches on the front, which contributes to the overall weakness.

 

[maxamillion2345]

What you're describing is shock loading, you can't know until it happens.

 

[Jbone]

Interesting! Learning....
Seems to me like they should have carried the big ring legacy over to the 80! So despite forward drive in a 40/60 being on the reverse cut side of the gear, an 80 series is still week and prone while in reverse...

What you're describing is shock loading, you can't know until it happens.

I am assuming you are referring to the actual failure happening?

 

[maxamillion2345]

Yes, theres not really any warning, it's a sudden failure caused by shock loading of the teeth.

 

[1973Guppie]

it should be mentioned though that you should avoid reversing the truck and cranking the wheel right or left. This is a sure way to break a birf, especially if you are butted up against a rock......