Driveshaft between T-case and Tranny...

[IHASFIP]

This is a completely stupid question. I even know it is a stupid question, for grins and giggles I will ask anyways. The halfshaft the goes between the T-case and the tranny has 4 bolts on either flange that hold it on. And I know, and I am sure you all will tell me, but is there any reason for all 8 of these bolts to be slightly loose. Like loose enough that you can spin the nut and bolt combo in the hole with your hand. I assumed they shouldn't. But all 8 bolts are like exactly the same looseness. What I mean is the nut on all 8 bolts is off the exact same amount, and the nuts are nylock nuts, so.... go ahead. Flame away.

D

 

[doghead]

They need to be tight. They are very prone to getting loose. They should have lock-nuts on them. If your are loose, it is best to replace with the correct grade and type fasteners, and check them often. They will come loose.

 

[IHASFIP]

OK, cool. That is what I assumed but even my mechanic was starting to wonder after we measured and saw all the bolts were loosened the same amount. I will tighten them asap. Thanks

D

 

[Westech]

on my deuce I had to at least twice a year go and tighten all the drive shaft bolts. I installed new one with lock washers and nuts and the same thing. Just the way it was with mine. I did not have any vibrations at any speeds but they would still loosen up.

 

[gimpyrobb]

We know you have had screws loose for a while now, Rich.

 

[Westech]

you know if I was 1/2 as squared away I am in uniform as I am off duty I would be prez of the USA by now. Its like night and day lol

 

[scooter01922]

For your future reference, they should be 1/2 -20 grade 8 hardware and use the deformed thread locknuts NOT the nylocks. I would just toss in new bolts and new locknuts, not that the old ones are probably that bad but they may have been torqued to the rights spec in the first place. If thats the case they should be replaced as technically they are only good for one go at correct torque. Which for reference is mega tourqued...the official spec is near impossible to actually attain while under the truck IMO.

 

[IHASFIP]

Ok, well I got under it and tightened them. They weren't the nylocks but were the deformed locknuts. I tightened them tight. As tight as I possibly could get it. But while under there I noticed my new lower radiator hose is leaking...again. And The hose between the thermostat housing and the waterpump is also leaking. Stupid old hoses. I will get those changed this weekend hopefully. Damn little grimlins keep popping up. Need to replace the oil pressure sending unit or the gauge one. Haven't determined that yet.

D

 

[docfarmall]

They need to be 675 newton units of torque

 

[Kennay]

Those commonly get loose on our bucket trucks at work... even with nyloc nuts and a lock washer. Weird.

 

[tm america]

hey guys i wouldnt use lock washers in something that recieves so much stress . put new grade 8 bolts with nylon lock nuts and loctite em to just to be sure lock washers have the tendincy to loose thier spring and crack under constant beating.also use fine thread bolts they dont work loose like coarse threads do notice most of the bolts are fine thread on the truck for that reason

 

[Kennay]

Ours have grade 8 in M8x1.25

I've never seen a lock washer crack. I have seen them flatten, and that is about it.

 

[Jones]

All the baby HEMTT's drive line bolts are fine-thread grade 8s with deformed thread locknuts against flat washers... no lock washers.
Most of us, me included, tend to re-use but I've yet to find any fastener mfr that recommends re-using the deformed thread locknuts. They're a one-time deal-- like axle u-bolts and their nuts.

 

[tm america]

i see lock washers cracked all the time sometimes when they loose their tension they will spread out so the ends dont touch.grade 8s with pinched lock nuts and loctite is the only way to go ,i dont know of any manufacturer that uses lock washers on a nut-bolt combo on drive shafts.the only time they use lock washers is with u-bolt type .but thats a totally diffent set up

 

[Nonotagain]

If you are really concerned about the nuts getting loose again, have the bolts cross drilled for safety wire and use a castle nut. Safety wire all of the nuts together.

As for reusing the deformed thread nuts over again, in aerospace componets, deformed nut locking features are required to be fully functional for ten cycles.

Clean the fastener, if required, install with light lubrication, then torque to recommended specified value. You may need to use a box end crows foot wrench to achieve the required torque if space limits access.

 

[IHASFIP]

I am not really concerned about it. It happens. If they loosen again I will tighten them back up. Not a big deal. When they do loosen again I will replace them with new nuts and bolts and some loctite.

D

Oh and I have seen lock washers crack. Matter of fact one of the mirrors on the truck has a lock washer that is broke near in half.

 

[Scrounger]

The nuts that hold the jack shaft bolts are notorious for coming loose. Any good quality grade 8 bolt and nut will work, however the “correct” nut will be a FLEXLOC nut by SPS fasteners. The FLEXLOC nut is designed to be used several times. When there is no longer resistance when tightening them they should be replaced. Just as important is the bolt. There is a torque value on fasteners and if that is exceeded the fastener will stretch, with the result that the fastener will not remain tight. I believe the reason most of the jack shaft bolts come loose is because of metal fatigue from age and over tightening.

 

[Dominican Driller]

On my old '67 deuce (which has been surviving in a 3rd world country for who knows how long before I got a hold of it), these bolts come loose all the time. It only had 5 out of the 8 when I got the truck. I haven't been able to find the correct bolts in this country for it so I came up with a good fix. Just leave the floor pan off and a couple 3/4" wrenches in the glove box. Just do a quick check before you start out for the day and tighten when needed.

 

[Speddmon]

I know this thread is already a few months old, but when I pulled my transmission to clean and eventually replace the clutch, my jack-shaft bolts were loose as well. Some tips and tricks I used on mine were.

1) If they are loose, it only takes a few minuted to remove the passenger seat and tunnels to be able to get into them properly to apply the correct torque. (my tunnels were already out to do the tranny)

2) If they are loose anyway, take them out one at a time and clean them with a good de-greaser and install new nuts like was mentioned several times in the thread, but when you reinstall the bolts, apply some blue loc-tite to the threads...then they will not come loose any more. If you've never used loc-tite, you really should...It's the best. Make sure you use the blue stuff and not the red. If you use the red loc-tite, the only way you're getting them back off is with the smoke wrench.

Just a little edit, for those who care, Loc-tite now makes their products in a semi solid form called "Quik-Stix" They are the same loc-tite formulas that you get in the liquids, but they are just like a lip-stick tube and are great for keeping in the tool box. I have at least one tube of each product on hand at all times. And I use them often.

 

[gt40072004]

I learned about this the hard way. I just bought a 1968 Kaiser Deuce and made it about 200 miles when I lost three out of the four bolts on the short shaft. The result was what sounded like an explosion which was the sound of an eliptical orbit of the drive shaft that broke the transmission bell housing 360 degrees around. The input shaft on the transmission also has an interesting angle now. I have not gotten into the clutch yet to see what it looks like. Needless to say I should have checked this website before picking up the truck. I will post pictures of the damage when I am able.