I think My Tranny main shaft may be bent?

[650savag]

Earlier this year I had a u-joint come apart with me and bent the short section of the driveshaft that splines up into the tranny. After a bit of a struggle, I was able to extract the bent shaft. I found a good drive shaft at the jy and replaced the rear seal and installed the good drive shaft and it seemed fine for a few hyundred miles. A few weeks ago I noticed a slight vibration between 50 - 60 mph. It wasn't noticible at lower or higher speeds. The vibration is getting worse and I'm starting to hear one "clink" or "ping" sound when I dis-engage the clutch and start to pull off. I have noticed a small amount of transmission oil leaking out of the seal. I also notice a bit of a binding feel when I start driving it every time. It's a 78 kc with a 5 speed. Could some of you guys give me some ideas what is going on? I'm afraid that I may have bent the main tranny shaft when the u-joint came apart and possibly has wiped out a bearing in the transmission and my rear seal. I was hoping for a bad u-joint but I have checked those and if one is bad, I can't really tell it right now. Here in NW Louisiana, I don't have the luxury of having jy's with several 620's laying around. The one that I know of is an auto tran. If it is the transmission shaft, approximately what am I looking at to have it repaired/rebuilt? Are there places to get new parts for these old 5 speeds? Any and all suggestions will be appreciated. I sure want to keep "Ole Blue" on the road! Thanks, Dan

[datzenmike]

Classic dry U joint if it sounds like a small hammer tap on the hollow d/s when taking off. That's the needle bearing tight and dry or rusty. If you leave it, it ill start to squeak. I assume you didn't replace the two U-joints when you replaced the d/s? This could cause the d/s to wobble slightly and vibrate as well as causing the rear seal to leak.

 

http://forum.ratsun.net/showthread.php?t=2357

 

Could be front or back... or the middle one. They are about $15 or so new maybe a bit more if you get the good ones with the grease nipple so you can grease them every tune up.

 

Pretty sure this is the problem and is easy to fix.

Edited December 23, 2008 by datzenmike

[jesusno2]

Its possible those 5 speed input shafts are fairly small. Back in the 90's I had a nicley built 620 with a lz hybrid motor and I busted the input shaft off 2, 5 speed trans.

[datzenmike]

Yeah the FS5W71B type was ok for use up through the inline sixes but when the VG came out in the mid '80s it was up graded to a C type with larger counter gear bearings. (and more) They were known to fail and take the rest with it.

 

http://i138.photobucket.com/albums/q251/datzenmike/Tranny/transNAPSZ5spdbroken.jpg[/img]"]

 

Not a good picture but if you look at the front of the lower counter gear you'll see what's left of the front bearing race. The balls and other pieces fell out when I drained the oil. Counter gear snapped off at the adapter plate! Anything's possible.

Edited December 23, 2008 by datzenmike

[650savag]

It does sound like the classic dry u-joint "ping" and I'm praying that is what it is. I checked out the u-joint replacement thread that you postedbefore, datzenMike and it is great stuff. I can get the u-joints here at O'reily's for $14 and I have replaced some in my 78 and my 80 720 kc. I usually can't identify a bad one until it gets bad enough to really start vibrating and sometimes has gotten loose and eaten away at the yokes. I'll jack up one wheel and get under there again and check them all and hopefully I will find a bad u-joint this time. Jesusno2 is calling the shaft that splines to the driveshaft an input shaft. Is that right or is that the main shaft? Dan

[jesusno2]

Wow datzenmike nice carnage pics man!!! I don't miss that mess for sure! The input shaft is the splined shaft that goes into the back of the engine. The tail shaft is the splined piece that the D shaft goes too.