Drivetrain rebuild Question

[TexasTruck72]

I went to have my '72 F-100 looked at today by the garage I trust to do most work on it that I cannot due to time & facilities.

I have had some problems with loud clanging sounds coming from it lately. My mechanic told me that I ought to think about having my drivetrain rebuilt. His reasons were that the spline part of my 2 piece drivetrain had froze up and wasn't moving freely and that my U-joints were probably worn-out. Does this make sense? I believe he is somewhat right about his diagnosis, but I am trying to figure out if it is really necessary.

The sounds I've been hearing sound like its coming from below & behind the bench seat(outside of the cab). When I accelerate, I hear loud clanging and rattling sounds for 3-7 seconds and then it goes away until I shift into 2nd gear and I hear it all over again. I usually don't hear it when I get into 3rd gear(highest gear on my truck). Seems that when the drivetrain is under load, it flexes & binds, causing the bushing halfway down the drivetrain to rattle around(causing the metallic pinging sound). If the splined part of my drivetrain wasn't frozen up with rust, it might be able to move back & forth when needed. Not exactly sure if I'm correct and or what to do here.

Any input, thoughts, advice, etc would be greatly appreciated.
The truck drives right now, it's just annoying hearing that loud banging/clanging noise when accelerating.

[Racer Z]

I tend to agree with your mechanic based on what you just described. If you let it go it's only going to be more expensive to fix later. I've seen drive shafts fall off while driving. You don't want that.

Check out this Mythbuster episode where they do make a driveshaft fall off a speeding car. It's five parts. One hour total.

part 1: http://www.youtube.com/watch?v=pCrZvoOX3X8
part 2: http://www.youtube.com/watch?v=mZIs6IBqWMQ
part 3: http://www.youtube.com/watch?v=wI7CwPezgfk
part 4: http://www.youtube.com/watch?v=n8S3THapVpI
part 5: http://www.youtube.com/watch?v=zEdj1g7sBHg

[knightfire83]

Think your mechanic is correct about the u-joint(s).

However it is unlikely that the slip joint on the drive shaft is completely froze up, this joint flexes every time you hit a bump. If it couldn't move at all, things would be breaking. Likely it just needs a shot or two of grease.

U-joints are around $8-12 a piece, and you have three if you have a two piece drive shaft. You could have just one bad one or multiple ones on the way out. It would be good insurance to have them replaced if they are bad. If you lose one you wont be going anywhere.

Labor is what will cost you the most. If you know what you are doing the replacement process is rather easy and could be done within a hour and a half for all three.

There is also a carrier bearing for a two piece drive shaft where the two shafts meet. If you want to be really thorough, have that checked too.

[knightfire83]

Video series for replacing a u-joint.

http://www.ehow.com/videos-on_510_repla ... joint.html

[TexasTruck72]

Think your mechanic is correct about the u-joint(s).

However it is unlikely that the slip joint on the drive shaft is completely froze up, this joint flexes every time you hit a bump. If it couldn't move at all, things would be breaking. Likely it just needs a shot or two of grease.

U-joints are around $8-12 a piece, and you have three if you have a two piece drive shaft. You could have just one bad one or multiple ones on the way out. It would be good insurance to have them replaced if they are bad. If you lose one you wont be going anywhere.

Labor is what will cost you the most. If you know what you are doing the replacement process is rather easy and could be done within a hour and a half for all three.

There is also a carrier bearing for a two piece drive shaft where the two shafts meet. If you want to be really thorough, have that checked too.

Thanks knightfire83. I agree with you on the slip joint. I guess mine moves a tiny bit, but it kinda rusty. I pumped some grease into it the other day with my grease gun hoping that would help.

Do you know where the carrier bearing can be found/bought? I looked up the U-joints, but haven't found the carrier bearing.

[TexasTruck72]

I tend to agree with your mechanic based on what you just described. If you let it go it's only going to be more expensive to fix later. I've seen drive shafts fall off while driving. You don't want that.

Check out this Mythbuster episode where they do make a driveshaft fall off a speeding car. It's five parts. One hour total.

Thanks Racer Z. I saw that episode of Mythbusters recently. That would be a terrible thing to have happen.

[fordman]

yes it is probably u joints making that noise. the spline do move back and forth when the springs flex or rear end moves. the carrier bearign can be had almost anyplace that sells autoparts.

[knightfire83]

Carrier Bearing:

(Same bearing different manufacturers.)

Part No. S-HB-88107-A $16.99
http://shop.advanceautoparts.com/webapp ... 8954114___

or

Part No. HB-88107-A $20.99
http://shop.advanceautoparts.com/webapp ... 3851829___

To replace this item it usually requires a press, so a shop would likely have to install this one for a couple bucks.

[TexasTruck72]

Well, yesterday I had my entire 2 piece driveshaft rebuilt by Drive Line Service of Atlanta. I am very pleased with the results and the relatively affordable price of $225.

My F-100 drives so much better now! I didn't realize how far my driveshaft's condition had gone down. The drivetrain is so much tighter and stronger now. My u-joints were pretty much shot and had lots of play in them, even with grease. That explains how I was able to roll my driveshaft back and forth with my hand when the truck was parked. Now, the truck is also much quieter while driving along. No more humming, clanging, rattling, and whining sounds from below.

Atlanta Drive Line Service specializes in driveshaft rebuilds and replaced all 3 u-joints, the carrier bearing, stripped the shafts, repainted the shafts, rebalanced the shafts, lubricated all fittings, and reinstalled it for me. I know I could have done some of this work myself, but since I don't have a lot of experience in dealing with driveshafts & u-joints and the fact that's I'd be doing all of this in my crumbly driveway I figured I felt better letting experts do the job. It was easy, just brought the truck and waited 2 hours til it was done.

If you are in Georgia, and need any work on driveshafts(whether it be for a bump or not), I highly recommend these guys.

[390Nut]

Very good price to have it rebuilt AND removed/reinstalled.

I had mine done about 8 years ago, and it cost me $190 just for the rebuild/rebalance, with me bringing it to them (Drivelines Northwest)

[sargentrs]

Not being a smart alec but I had the same problem and told myself "great, now my center bearing's going out". Stopped in the parking lot of an Ace Hardware and crawled under it for damage assessment. One of the bolts was missing and the other nut was already half off. I have no idea how that happened. Went in the store, bought new bolts and locknuts, bolted it back in and Ta Dah! the noise went away.