Kaboom! Blown Front Diff (1 Viewer)

[akarilo]

Yes, more carnage since going to 37's. First it was a birf, then a rear axle twist, now the front R&P. Got Long's after the blown birf, so that in turn transferred the fuse to the ring and pinion I guess.

Scenario: Attempting to back up a fairly steep incline and apparently got a little bound up. Did not apply too much throttle, but... Boom! Moral of my experiences; be very careful in reverse in these 6000lb rigs!

Here it is.

 

[kidglove13]

That is one of the weaknesses of high pinion reverse cut thirds
They are strong a hell going forward but can be weak in reverse

And as you know the 5:29 gears are going to be a little weaker and thinner than the stock 4:10's

Maybe Cryo the next set

 

[plutonius]

Ouch!!! How did you limp home? Did you pull the DS and axles on the spot?

 

[jcardona1]

Whoa! What R&P, stock? Aftermarket?

 

[kidglove13]

Ouch!!! How did you limp home? Did you pull the DS and axles on the spot?

Lock center diff, pull drive shaft and drive flanges and away you go

 

[akarilo]

Ouch!!! How did you limp home? Did you pull the DS and axles on the spot?

Limped it into camp and pulled the drive shaft and axles out then reassembled. That way I can still tool around with an empty axle housing while getting the diff repaired.

 

[allan man]

Damn! How hard do you wheel? I had plans on doing 37s from the 315s in the future......Thanks for sharing your experience.
something definetly to consider on the budget to improve the weak links.

 

[Delancy]

Maybe Cryo the next set

Cryo'd the 5.29s at the recommendation of powderpig, but recall him stating that it was an effort to combat wear, more so than a strength gain.

I'm no metallurgist, so can't definitively say.

So we need spare thirds now, akirilo?

We're gonna need a trailer to haul the spare parts.

How hard do you wheel?

Kia's have a hard time keeping up.

 

[Tapage]

Scenario: Attempting to back up a fairly steep incline and apparently got a little bound up. Did not apply too much throttle, but... Boom! Moral of my experiences; be very careful in reverse in these 6000lb rigs!

locked .. ? over a rock ( hi traction ground ) .?

 

[VCCruzr]

Scenario: Attempting to back up a fairly steep incline and apparently got a little bound up. Did not apply too much throttle, but... Boom! Moral of my experiences; be very careful in reverse in these 6000lb rigs!

Backing up a steep incline is how I blew my birf after going to 37s. After hearing this, I think I will stick with my stock axles and have them be the weak link as they are cheaper to replace than gears.

 

[scottryana]

Yep same way I did mine. Backing up a steep bank while turning around on a tight trail. Rear end was probably 5-6' up in the air lots of weight on the front end, but it was not abusive.

 

[TheBigBoy]

The 5.29's arent a little weaker than 4.1's. They are alot. In reverse all the weight and load was on the front diff. So its not the reverse factory (coast side), its more the load factor. Where you running a solid pinion/colar and good gear pattern?

 

[pittsburgh phil]

i just posted stuff on an axle swap. my 37s really hurt my truck. i wish i would have stayed with the 35s. and also i did not know about the weakness of the diffs in reverse. my rig is parked in a parking lot on a mean slope on a dead end street, the only way i can get it out of where its parked is backing up the steep hill every day. it cant b good for my diffs and my back one is about shot now. i have a 91 and am replacing with a 95 with disk brakes

 

[akarilo]

The 5.29's arent a little weaker than 4.1's. They are alot. In reverse all the weight and load was on the front diff. So its not the reverse factory (coast side), its more the load factor. Where you running a solid pinion/colar and good gear pattern?

Good pattern, very experienced installer, crush collar. If I'm not mistaken, even Zuk advised that a solid spacer was not necessary for this application.

 

[TheBigBoy]

A solid colar is always nessesary. It means 1 thing. Under heavy load it will not crush. You could have easily crushed the colapsable colar under load = the pinion is now too shallow and riding on the edge of the teeth. Weakening your diff even further.

 

[Wrench]

I've broken 4:56's on 37's so any strength gain with higher gear ratios is very minimal. Now I run 5:29's with 40's no breakage yet.

 

[scottryana]

Oh yes sorry I was on 4.88's so it's not any particular ratio

 

[Wrench]

After going longs the r&p is now the weak link. There must be a way to get around this. I hate to swap in non toyota axles to correct the problem. Have we just reached the limit on what the stock axles can handle?

 

[scottryana]

Next step would be cryo after that not much you can do

Slee tried a 9.5" center section but its running on the coast side which is no good. They broke 2 in a day.

This problem and its solution depends on the depth of your pockets.

 

[Wrench]

Delancy in post #8 said cryo was more for wear than strength. Has anyone blown a cryo'd r&p?