The Big Badda-Boom! T-case questions

[tRustyK5]

That vibe on not quite coast sounds like U-joints to me, or driveline angles being slightly off. 465's are stupid strong, and generally don't vibe or whine even when beat to death. A 4" lifted K5 will commonly have driveline angularity issues though.

 

[blzrdrvr]

That vibe on not quite coast sounds like U-joints to me, or driveline angles being slightly off. 465's are stupid strong, and generally don't vibe or whine even when beat to death. A 4" lifted K5 will commonly have driveline angularity issues though.

That's the second time i've seen that suggested for this problem, but on someone else's post.
i will check that out. Here's a good article on angles: http://www.therangerstation.com/tech_library/pinionangles.shtml

"Pinion Angles (SIngle Carden Driveshaft) - The pinion angle should be the opposite of the transmission (or transfer case) angle. If the transmission points down 5* degrees, the axle pinion should point up 5* degrees. And then, allow 1* to 2* for axle twist under acceleration, so a better angle at the pinion may be to point it up 4* degrees."

I don't know if the noise started before of after the lift. it's been a long time. i know my u-joints are good.

Does anyone think a bad DS angle would cause a TC to grenade?!?

 

[blzrdrvr]

Im getting really screwed up here. The bottom of the TC says 5*, the bottom of the diff says 10*. The face of the tailhousing says 85*, and the bolts on the pinion bearing (14b ff) say 80*. Who is telling the truth?

 

[jekquistk5]

Measure output and input only. All other points you measured are not in the same plane. Measure the output of the tcase/seal, and the yoke on the rear axle.

 

[blzrdrvr]

I see what i did. Still the same difference. 5* and 10*.

 

[Mastiff]

Im getting really screwed up here. The bottom of the TC says 5*, the bottom of the diff says 10*. The face of the tailhousing says 85*, and the bolts on the pinion bearing (14b ff) say 80*. Who is telling the truth?

All those numbers are consistent I think (85+5 = 80+10 = 90). Sounds like you're 5* off from the ideal of having the angles equal.

 

[blzrdrvr]

I see what i did. Still the same difference. 5* and 10*.

yeah...just a mirror. not used to working with an angle finder

 

[Blue85]

the RE is a 14b FF...so the pinion is a bit higher than the stock unit that was under it with the same 4" blocks..

See, you identified the problem a few pages back. The pinion only moves about an inch between 10B and 14B rear ends. It's higher because the angle has changed.

 

[dyeager535]

Does anyone think a bad DS angle would cause a TC to grenade?!?

Absolutely. Had a friend with an 84(?) K5, which I inspected before purchase. As bone stock as a driven vehicle that age can be. After purchase, she threw a 4" lift on it, and it was a street only truck. Driving down the freeway it did the same thing yours did.

With good u-joints, and mismatched u-joint angles, no lift, I get a vibration I am quite certain is from the bad angles. Short wheelbase does not help, as the operating angle is also a factor, even if the front and rear joints are set to the same angle.

 

[blzrdrvr]

k. rotated the blocks 180*. now i am 3* too low. with wrap that is supposedly 2* out. noise persists. it's not in the drive shaft. according to the internet, it's not the pilot bearing. looking hard at the tranny. tomorrow i will stick a finger in her and check for a shiny sheen in the fluid.

 

[Fordum]

Yeah, remember the pilot bearing does not rotate when the clutch is engaged.

Well, unless the clutch is slipping..........

 

[blzrdrvr]

then it's the tranny ? sigh. thanks fellas! (not sarcastic)

 

[blzrdrvr]

Well, took The Old Man for a ride today after installing the shims...i reproduced the sound, and he says my DS is out of balance. i hope this is all. The local drive shaft place is closed on weekends, so i have to wait until monday to see how fast they can turn around this job. i can get a ride to work with the GF, but at 5:30am...not much to do until opening at 8.

 

[blzrdrvr]

got the DS balanced. (for free! woo!) dang, it's so strange to have no vibrations, after owning this truck for nearly a decade. i thought it was all of just being an old truck. It's like K5 meditation. in the zone. smooth like buttah.

The noise that i feel in (third gear, approx: 40-45 mph...and higher) the stick and the pedal persist. I have yet to reproduce the noise at highway speeds, because as before the balancing of the DS, it was frightening. Will attack the highway this weekend, yet i am sure of the result.

anybody wanna throw darts at the board?

 

[blzrdrvr]

Some folks here wanted a reason why the t case greneded. I think i have an answer, both for you and myself. Went looking for a transmission, went to midwesttrans.com. there, they mentioned the most common issue with the sm465 is a rough bearing noise near the clutch area, caused by a bad pilot bearing. Sounds like what i got, plus an evil vibration, even with new u joints and a balanced shaft. So why did the t case grenade? Take an old tcase, and vibrate the literal stuffing out of it from both ends and see what happns. I belive we have an answer. I guess my next step before rebuilding the tranny is a pilot bearing.