Desert Trip V: Canyonlands Maze District

[modernbeat]

...Curious if anybody has ran into this problem on 14 bolts before. I am sure open to some ideas

Larry, while I have not seen it on a 14 bolt (because they are rarely in roadracing cars) I have seen similar puking from a lot of axles, particularly the 8.8 installed in recent Mustangs with the Traction-Lok LSD.

What I've seen is that clutch-style limited slips or lockers add a LOT more heat into the rear diff fluid than Torsen style LSDs or selective style like the ARB. The extra heat first blows the fluid out of the vent, then starts taking out bearings and seals and eventually can even affect the brakes in a racing application. In most cases when I can change it out to a Torsen, the heat is reduced tremendously.

But, this heat really on shows up when racing, and working the differential action, and the locking, much more than what the designers thought the car would see. If you aren't experiencing a lot of wheelslip, or cornering hard, I'd look and see if something else was causing the differential locker to work when it shouldn't be working. Something like one of the rear tires being taller than the other.

 

[y5mgisi]

Is it possible that is why they added more fins on the later 14 bolts? To aid in cooling?

 

[y5mgisi]

What if you moved the vent to a different location on the axle?

 

[Larry]

Larry, while I have not seen it on a 14 bolt (because they are rarely in roadracing cars) I have seen similar puking from a lot of axles, particularly the 8.8 installed in recent Mustangs with the Traction-Lok LSD.

What I've seen is that clutch-style limited slips or lockers add a LOT more heat into the rear diff fluid than Torsen style LSDs or selective style like the ARB. The extra heat first blows the fluid out of the vent, then starts taking out bearings and seals and eventually can even affect the brakes in a racing application. In most cases when I can change it out to a Torsen, the heat is reduced tremendously.

But, this heat really on shows up when racing, and working the differential action, and the locking, much more than what the designers thought the car would see. If you aren't experiencing a lot of wheelslip, or cornering hard, I'd look and see if something else was causing the differential locker to work when it shouldn't be working. Something like one of the rear tires being taller than the other.

Thanks Modernbeat,

That is great info but I am not running a clutch type limited slip or locker. I’ve been running a Detroit in this thing for close to 10 years.

The axle having premature ejaculation started last March on the Death Valley trip. Then again in May when I ran down to Flagstaff. The summer prior to that I had converted the rear drums from the typical 70’s ¾ ton 10.5 axle 11” drums to 1 ton 13” drum but I also replaced the cheap and loud “Genuine” brand ring and pinion to a Yukon set sometime around then but I can’t remember exactly when the new ring and pinion went in. One of these projects brought on this new problem. Now I just have to figure out which is the culprit.

Is it possible that is why they added more fins on the later 14 bolts? To aid in cooling?

Could be but I doubt it is the entire reason. Millions of these axles have been used from 1973 up until they fin'd version came out in the 90's. I doubt the fin's alone would prevent this and at this point there is no evidence the oil is overheating anyway.

What if you moved the vent to a different location on the axle?

Nah, I suppose I could drill a new hole some place for a new vent but I shouldn’t have to plus if it is building pressure the oil will get pushed out regardless where the vent is at. I need to figure out the problem rather than reinvent the wheel.

The only thing I noticed that surprised me is the vent hole is right above where the carrier adjuster collar is on the left side. The adjustor collar actually covers the vent but there is still plenty of room for air to get by. Although with using thick gears I wonder if there is splash coming off of the left carrier side bearing and getting slung up into the vent hole. That still would not answer as to why it keeps blowing axles seals and why it stalled on me in Death Valley. Friggen mystery!

 

[TREA18]

Larry,

I know you know way more than me about these trucks, but I thought I read on Ck5 about 2 years ago about someone having a similar issue and they changed how the vent line ran. Maybe a search could find it, but the vent line went down then up or something like that. I'm not sure, but it helped his problem . Hopefully someone might remember.

By the way I love your trip reports and the abilities you have with your truck to spend days in places few people will ever see is really cool. Thanks for all the pictures, as well..

 

[y5mgisi]

I think your on track with the gears splashing the oil over to the vent hole. I wonder if it's also possible that the thick gears, being more material, expand more with heat shoving the ring into the pinion causing the drag feeling your talking about.

 

[campfire]

By the way I love your trip reports and the abilities you have with your truck to spend days in places few people will ever see is really cool. Thanks for all the pictures, as well..

My thoughts exactly. I love seeing the trip pictures. Writeups like this one continue to expand my bucket list.



(No, I don't have any new ideas for the axle issue.)