So i started hearing this clicking noise at 5mph and below with my getrag. Could not figure out what it was! Looked at back of trans while checking fluid level and the nut that holds yoke to the output shaft is OFF the shaft. Just rolling around. the ujoint has kept the nut from falling off the truck and being lost so i still have the nut. Drove like this for 1000 miles or so before i found what it was. Below 5mph the nut would click around until the speed was enough to pin it to one corner and centrifugal force would hold it there. I have not driven it since thursday when i found it but i need the truck for work come monday. I read that torque spec for nut was 280 ft-lbs. Is this correct??? My main question is has this caused any damage to the transmission??? The yoke is still tight on the shaft and does not appear to have moved at all. But i have seen some trannies where this nut holds the shaft against a bearing and that the bearing could be destroyed when this nut is not at proper torque spec. I really cant afford to redo tranny right now nor can i find one anywhere. Tranny feels ok but i am not sure how getrags work. Please some one tell me I have not toasted a good trans!! any help is greatly appreciated!!

 

for the 2wd, I don't think you've hurt the trans if it hasn't popped off. The output yoke slips over the output shaft and there is a seal that seals the yoke but the rear main bearing preload is set from the tailhousing, not the yoke. I would take the driveline off, pull the yoke all the way off and inspect the shaft and yoke, and if there is no damage/shavings/etc I'd just put it back and and torque to spec with some loctite even. No need to rebuild the getrag because of this but you were lucky not to lose the driveline!

 

Sweet
I cant believe i didnt see it sooner. Glad its nothing to lose sleep over.
Losing a drive shaft would not have been fun!!
Thanks for the quick response! Do you think this could cause my speed to act up as well? It jumps around a bit since i bought the truck but got worse since the "clicking" started. Thanks a bunch for the info, i really appreciate it!!

 

actually yes because the yoke is prolly sliding a bit and then right in front of that is the nylon speedo gear around the shaft.... it could be related

 

I hate to tell you this but the same thing happened to me a couple of years ago. I was pulling a 2-axle car trailer from PA to OK and somewhere in Ohio I started to feel a strange vibration. Looked and couldn't find any problem so kept on driving and finally in MO at a rest stop, I noticed an oil leak. Checked it out and found the tailshaft nut bouncing around in the u-joint and oil leaking from the rear seal. The bad part was that just days before, I had installed that transmission as a low-mileage reman that I pulled from a wrecked truck.

Long story short, for some reason, loss of oil or wobble or whatever, that transmission always made noise after that and 23K miles later, it was totally shot.

If I were you, I'd double check the fluid level and keep driving it but start saving for a rebuild in the near future and if you have time when you can have it down, slap a new set of bearings in there. Sorry but I'd bet that there was some damage from that nut coming loose.

 

I had the equivalent nut come off of a NP205, going about sixty, with a gooseneck-load of cattle.

Three big truck-shaking lunges, then KER-BANNNGGGG!!, the forward end of the shaft started hitting fuel-tanks and such.

It almost wrecked me.

Broke the bell-housing, broke a mounting ear off the transmission, knocked loose many wires, etc.


Were I you, I wouldn't panic about your situation.

Lay the nut face down on an anvil.

Take a dull chisel and "mash" the outside thread in three equidistant spots; this restores it's original locking ability.

Examine/clean/polish the shiny portion that rides the seal.

In the absence of a torque-wrench, lay down on it with a 3/4 breaker-bar, pretty snug.

Use LocTite.

Check it occassionally( I'm gonna look at mine right now).

 

I heard the same noise, after I had noticed the speedo would lose 20 mph any time i let off the throttle. I found the nut just like you and unbolted the driveshaft and replaced the seal. Once done the speedo worked fine and I had no other issues. That was about 2 years ago.
-Jim-

 

The speedo drive gear rides on a worm gear on teh output shaft.
There is (from front to back) the worm gear, a bronze or plastic spacer, the seals, etc, and the output yoke, then the nut.
When the output shaft nut is loose, it allows the worm gear to travel on the shaft, causing problems with the speedo...

 

Chris- right idea, but the details arent quite right.

There are 2 spacers in the tailhousing on the output shaft -one on either side of the speedo gear. The gear itself is plastic with a steel sleeve in the center. The nut tightens the speedo gear and spacers. If you have a problem with a jumpy speed on a 2wd, that is the first place I'd recommend to look- if stuff is loose, the nut can turn on the shaft, just like CHris said.

12valve@heart- your tranny going south was related to the fluid loss. There is no way bearing preload can be affected by the output/ yoke nut coming off.

soot4brains- Get the right size socket (I THINK it's 1-3/8 or 1-5/16), and about 4ft of cheater pipe. Apply a liberal dose of Loctite (you wont get too much, trust me), and crank on 'er. FSM calls for 280ft-lbs.

Daniel

 

Dont know how I missed this thread. I had the same problem on my 92. Just after my cluth was replaced. In a hurry I just tightened it with 1/2 drive as hard as I could. I will be rechecking it this week, now.

 

You guys were lucky. When I noticed my speedo getting funny, I saw the output shaft nut rolling around inside the U-joint cage BUT there was a piece of the output shaft inside the nut. I had to replace the shaft and used this as a chance to do a much needed rebuild of the rest of the tranny. With advice and a pdf. getrag manual supplied by the guys on this site, I successfully rebuilt it for around $600. I should have replaced the input shaft as well but I will do that next time. I have put about 50k on it and it works well.