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BOILED GEAR FLUID IN 14BFF

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by KRAZIE87K5, Feb 26, 2002.

  1. KRAZIE87K5

    KRAZIE87K5 1/2 ton status

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    Ever been so pissed at yourself to run yourself over in your truck?

    Anyhow, I installed a perfectly good set of gears into the 14BFF today... in the snow... alone... and then test drove it. Got about 2 miles from the house, and came to a stop at a light. But the truck seemed to be breaking by itself. So I pulled into the station on the corner there to take a look. Soon as I hop out, I smell HOT gear oil. [​IMG] And then I look at the front... nuthin... rear... SMOKE. DOE! [​IMG] Bent down to touch the cover, and almost burned my fingers.

    Tried to think what to do... had no cell... had no one to bring tools... I had to limp her home. To leave a standstill, I had to gas her some, and then it would lurch forward like I was towing something. [​IMG] (little did i know it was the 14BFF axle under the back of my truck)

    Got it home doing about 10 miles per hour. Had a hell of a time forcing the rear axle to turn the tires in reverse up the driveway. Decided to pull the diff cover after I couldn't get to coloradok5.com (site was down)... [​IMG] the oil was literally boiling in there! [​IMG] Pulled the cover, draining the oil into a plastic drain pan.... the oil went RIGHT THRU it in about 30 seconds. [​IMG] I was able to remove the retaining clips, loosen the main cap bolts... and then tried to back off the collars on the left and right... NOTHING. [​IMG]

    Lemme guess now... ZERO PRELOAD, right? It would figure. I prolly overtightened the collars, BUT NOT VERY MUCH. Would that really cause the rear to heat like it did? I might have had 5ft.lbs. on them TOPS.

    Did I just fry my diff? I can see a little bit of the bearings, and they don't look really bad at all... but I can't see very much. I'm guessing from the way I had to push the rear diff up the drive (in reverse) with the front diff that, I probably fused the bearings to the races. Someone PLEASE tell me that I can reverse what I have just done - or I may have just F$^#@& my chance at getting to Disney... [​IMG]

    <font color=red>GOT MUD???</font color=red>
    <a target="_blank" href=http://home.attbi.com/~netwrite>Midwest Caravan</a>
    454/TH400/NP205 - 14BFF/D60/w/ 4.10s - 36" TSLs
     
  2. thebigdaddyof2

    thebigdaddyof2 1/2 ton status

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    Dan, Dan, Dan...what the hell happened? Did you install the entire pinion assy with the shim like I shipped? Did you mark the position of the bearing caps before disassembling and reinstall them correctly? And most importantly, did you check the pattern??? PM me.

    thebigdaddyof2
     
  3. KRAZIE87K5

    KRAZIE87K5 1/2 ton status

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    The motion sensing lights kicked on by the truck, so I ran outside to check on who was around the truck! [​IMG] It's the flippin' fire dept. They told me someone reported a gas leak... I told them to "sniff" under the truck... they guy comes out from under it saying, "yup, that smells just like natural gas!" They waved their little "gas sniffer tool thingy" near it to see if it was combustible, and it wasn't (thank god). The neighbors called when they smelled the smoke from my diff blowing with the wind down the block. DOE!

    It really does stink... I'm so bummed.

    <font color=red>GOT MUD???</font color=red>
    <a target="_blank" href=http://home.attbi.com/~netwrite>Midwest Caravan</a>
    454/TH400/NP205 - 14BFF/D60/w/ 4.10s - 36" TSLs
     
  4. KRAZIE87K5

    KRAZIE87K5 1/2 ton status

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    ANYONE?

    2 things:

    1.Torque spec on the main caps
    2.How tight to make the collars?

    Thanks...
    -Dan

    <font color=red>GOT MUD???</font color=red>
    <a target="_blank" href=http://home.attbi.com/~netwrite>Midwest Caravan</a>
    454/TH400/NP205 - 14BFF/D60/w/ 4.10s - 36" TSLs
     
  5. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Dan, the side adjusters are set previous to the bearing caps being torqued. It's been a year or so since i had mine apart but the adjusters aren't supposed to be tightened against the carrier with any real torque.

    Here'es a link to an article on Off-Road .com that shows the disassembly of a 14 bolt and the installation of a Detroit. It should help some. I can't recall the main cap spec's off hand but it's over 100 lb/ft.

    <a target="_blank" href=http://www.off-road.com/chevy/tech/detroit/> 14 bolt write up</a>

    Rene

    <font color=green>Dyslexics of the world...UNTIE!</font color=green>
    <a target="_blank" href=http://coloradok5.com/gallery/project_T2> tRusty pics...</a>
     
  6. KRAZIE87K5

    KRAZIE87K5 1/2 ton status

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    I torqued the caps to 100ftlbs so that wasn't the prob... the pattern looked fine to me... so it must have been the collars. I was a dumb @ss and didn't scribe the collars prior to releasing them, so that is likely where I screwed myself.

    I placed a call to a local machine shop today to get price to have them replace the bearings and seals in the diff, and return it to me complete... I haven't gotten the call back yet... but I will guess it will be around $300! The wife is going to kill me...

    -Dan

    <font color=red>GOT MUD???</font color=red>
    <a target="_blank" href=http://home.attbi.com/~netwrite>Midwest Caravan</a>
    454/TH400/NP205 - 14BFF/D60/w/ 4.10s - 36" TSLs
     
  7. HarryH3

    HarryH3 1 ton status Author

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    Those adjusting collars don't get set to a specific "tightness". They are adjusted until the backlash setting is correct. Then you lock them in place with the wire clips that fit into the holes in the collars. Finally, you torque down the main bearing caps. Your bearings may still be OK, but you may have overheated the heck out of the ring and pinion if there was no backlash between them. The pinion gear teeth in a hypoid gearset move in a sort of wiping action across the teeth of the ring gear. With no backlash (or worse yet, preloaded backlash) that would cause the gears to get very hot. Look closely at the gear teeth, especially the pinion gear, to see if the mating surfaces have been damaged. [​IMG]

    <font color=black>HarryH3 - '75 K5</font color=black>
    <a target="_blank" href=http://www.angelfire.com/super/ThunderTruck>www.angelfire.com/super/ThunderTruck</a>
    It's a great day to be alive...
     
  8. KRAZIE87K5

    KRAZIE87K5 1/2 ton status

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    Harry-

    I have looked at the ring - and I can't see any obvious damage... so I hope things are ok.

    So to fix the backlash being too deep, I need to add more shim to the pinion housing right? Where can I get different shims? Any ideas? Thanks...

    -Dan

    <font color=red>GOT MUD???</font color=red>
    <a target="_blank" href=http://home.attbi.com/~netwrite>Midwest Caravan</a>
    454/TH400/NP205 - 14BFF/D60/w/ 4.10s - 36" TSLs
     
  9. KRAZIE87K5

    KRAZIE87K5 1/2 ton status

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    And what about the pinion housing... does it only have one position, or are there multiple positions? Maybe I put that in differently?

    Geez, I wish I knew what to do. The shop asked for $350 to rebuild the axle without parts. OUCH. I really screwed this one...

    <font color=red>GOT MUD???</font color=red>
    <a target="_blank" href=http://home.attbi.com/~netwrite>Midwest Caravan</a>
    454/TH400/NP205 - 14BFF/D60/w/ 4.10s - 36" TSLs
     
  10. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    What exactly did you have apart Dan? That will help determine what is out of adjustment. There are two planes of adjustment, first is pinion depth. This should not have changed unless you removed or re-installed the pinion.
    The second adjusment is side to side on the carrier. The adjuster rings do all that...there are no side shims.

    You're gonna need a dial gauge to get the correct backlash and some marking compound to check the contact pattern.

    Using that link I sent earlier I'd go ahead and remove the carrier and check the bearings first though. Once the carrier is out go over everything with Brake Kleen and check the pinion and the ring gear. If the pinion and ring gear are OK and the bearings are OK then you'll have to set the gears up.

    Install the carrier and get the bearing cap bolts in but not torqued. Keep em just loose enough that the carrier will move sideways with the adjuster rings. I'm not sure what the correct backlash is though...

    Rene

    <font color=green>Dyslexics of the world...UNTIE!</font color=green>
    <a target="_blank" href=http://coloradok5.com/gallery/project_T2> tRusty pics...</a>
     
  11. HarryH3

    HarryH3 1 ton status Author

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    Yep, like Rene said, there are no shims in a 14-bolt FF for adjusting the backlash, it's all done by adjusting those side collars. (It's very similar to a Ford 9-inch or Toyota diff in the way that works). Only the pinion depth gets set using shims. Once the depth is correct, then you adjust the backlash to specs. Ya gotta have that "slop" in there to allow for expansion as the gears heat up (as you so rudely found out). [​IMG] [​IMG]

    I can't remember if the pinion housing is indexed so that it will only install one way or not. But I'll bet thatK30guy has had enough of 'em apart recently to know for sure. [​IMG]

    <font color=black>HarryH3 - '75 K5</font color=black>
    <a target="_blank" href=http://www.angelfire.com/super/ThunderTruck>www.angelfire.com/super/ThunderTruck</a>
    It's a great day to be alive...
     
  12. KRAZIE87K5

    KRAZIE87K5 1/2 ton status

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    Harry-

    I agree with the "slop" to account for the gears HEATING... I wouldn't know anything about that appherently! [​IMG][​IMG]

    Wes-

    Where are you bud? I need to know the spec for pinion depth. PLEASE!

    Thanks Harry, Rene, and [hopefully] Wes! You guys rock!

    -Dan

    <font color=red>GOT MUD???</font color=red>
    <a target="_blank" href=http://home.attbi.com/~netwrite>Midwest Caravan</a>
    454/TH400/NP205 - 14BFF/D60/w/ 4.10s - 36" TSLs
     
  13. thatK30guy

    thatK30guy 1 ton status Premium Member

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    Damn! Finally read this thread and said, "wow!" to myself. I have never seen or heard of a problem like this.

    As for the pinion carrier support housing, it can only go on ONE way. It is NOT indexable. The reason is because the carrier has a hole in it where it allows the gear fluid to reach the bearings.

    If you remove the pinion support, check to make sure the hole is on the bottom of the carrier support.

    About the adjusting collars, what I do when I rebuild the 14FF, I set up the backlash after the pinion support is already in and check the pattern with compound.
    Once you have gotten the correct pattern, I remove the pinion support and check the ring gears "free spin". This "free spin" method will tell you if you have the adjusting collars too tight or not.
    You should be able to spin the ring gear by hand and let it spin with no load from the pinion for about 15 to 30 seconds, depending on how hard you spin it.
    If it slows down faster than 15 seconds, you have the adjusting collars too tight. Simply back off one hole and do the spin method again. Repeat as necessary, alternating adjusting collars.

    Once the spin is free and correct, throw the pinion support back on and recheck the backlash. Set the backlash as necessary.

    Hope all that helps. The adjusting collars on these axles can be a little tricky when tightening them. They must not be tight as to slow the ring gear down.

    My bet the adjusting collars were too tight causing the ring gear to "drag" and get hot on the bearings.

    If I were you, I would replace all the carrier bearings. Any amount of abnormal heat will be enough to warp the bearing cages. Do not take a chance of reusing the same bearings. New bearings are cheap insurance and a peace of mind. [​IMG]




    <font color=red>Only real men drive K30's!!!</font color=red> [​IMG]

    <a target="_blank" href=http://coloradok5.com/gallery/thatK30guy>The K30 Collection</a>
     
  14. HarryH3

    HarryH3 1 ton status Author

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    Just got home and took a look at some 14-bolt parts laying in the garage. Indeed, as Wes said, the pinion support is indexed. The bolt pattern isn't symetrical, so it will only install one way. I thought that I remembered seeing the hole that's drilled in it for lube flow and sure enough, there it is! So at least that couldn't have been installed wrong. [​IMG]

    <font color=black>HarryH3 - '75 K5</font color=black>
    <a target="_blank" href=http://www.angelfire.com/super/ThunderTruck>www.angelfire.com/super/ThunderTruck</a>
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  15. 84_Chevy_K10

    84_Chevy_K10 Banned

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    You're from Illinois, aren't you? 4.10 geared 14FFs are a dime a dozen. Just go get another one.

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     
  16. 84_Chevy_K10

    84_Chevy_K10 Banned

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    You're from Illinois, aren't you? 4.10 geared 14FFs are a dime a dozen. Just go get another one.

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     

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