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Triumph TR6 - U-joints

I hear a sound that, to me, says I have a bad u-joint. I've checked the differential mounts and they are not craked or broken. Is there any easy way to tell which of the six u-joints is bad? Also, my differential does move a bit up and down in the right-rear side mount. Should the diff move a bit on the rubber pieces or should I replace them. Thanks again, Jeff
Jeff Hall

Hi Jef
Not sure if easy way to find out which one is bad u joint. But your diff. should not move at all. Yes replace and replace all four mounting points with new polly bushes. Double check for cracks in the mounting points of the diff. Is the RR mounting stud cracked or broken? Maybe the sound is the diff moving as you put load on and off of it.
Good luck
Rick
Rick Crawford

All the mounts look and feel good. But the diff is moving when I put load on it. I'll replace the mounts. I should just be able to support the diff and replace them one at a time, correct?

Jeff
Jeff Hall1

Hi Jeff
I have a much longer answer to your question in another window but stopped as I went back and reread your thread. In both your entries you say the diff moves up and down. Is it loose or is it just putting torque on the rubber mounts and slightly compressing them? What does the noise sound like? Is it a single "thump" when changing gears or is it a noise that increases in frequency as speed increases?
To change the rubber mounts to polly mounts is a little work and you should change them all at the same time. As said I have another answer on how to change the mounts but is on hold till I hear what you say. What year is your 6?
Rick Crawford

My 6 is a '74. The diff is moving up and down on the right-rear mount when torque is applied, compressing the mount. The noise is just a thump, sometimes during gear change, engaging the clutch while at speed or starting out in first. That's why I thought it was a u-joint. The noise doesn't change, and I don't hear it all the time. Maybe the mount is just wore out allowing it to move like it does, as you said above, that might be making the sound. Thanks. Jeff
Jeff Hall

Jeff
Since you are 74 you have had the mounting plates reinforced by factory. I am not sure if it is the RR mount. Try this: From a stop position let clutch out (not all the way) and in with no throttle..you are not trying to move car but instead seeing if you get this noise. Do the same in reverse gear. Is it a thump as clutch starts to engage? Can you move the diff with your hands ar a pry bar..is it loose in RR mount?
Let me know...someone else is more than welcome to add there 2 cents worth.
Rick
Rick Crawford

Jeff, I have a 76 and have the same problem you are experiencing. However, my sound is more of a distinctive "click". I replaced all of the u-joints but still have the sound. Using a pry bar, I was able to move my diff while lying under the car and the click is coming from the right front mount. To anyone out there, does this mean I have the dreaded broken mount? Thanks, Mike
Michael Parkhill

Mike
The RH front mount is usually the first mount to break (if it has). This one takes the most stress as torque is applied to the diff when clutch is released. You said you could move the diff with pry bar. Does the mount rubber and bolt move as well or does the diff move up and down while rubber and bolt stays stable? Elaborate more on your statement re the pry bar while under the car and this click noise. The front bottom rubbers on both sides can be removed without having to lower the diff. I can not remember if just thread is accessable or if you can clamp onto unthreaded bolt shank. If you can clamp onto shank, protect the shank with a rag and clamp vise grip pliers onto it and see if any play or not. If thread just accessable then put nut on and do same. If it is the mount that is broken then the diff must come out and welding take place. Remember nyloc nuts are a one time on and should be replaced if removed. (4 main studs= 3/8-24, and 4 rear bolts = 5/16-24).
Jeff, have you tried my last posting test? Do you have the TRF spare parts catalogue? If so go to page 201 and read tech. note re this subject.
A question for both of you. Is the rear rubber mounting assembly attached on the bottom side (or top side) of the diff. mounting flanges as shown in TRF page 201? MOSS also shows mounted from the bottom. If so, the back 2 are easy to replace..it is the front upper 2 that are a problem. (sorry can not remember this one). Jeff same vise grip pliers procedure can be done to back mounts ( if mounted on bottom of diff. flanges). You will need to support diff. if you do this to both at same time. You will find the rubbers will need a little persuasion to come off the studs;-)
Regards
Rick
Rick Crawford

Hi Mike,

I too get a click sound from the back end when I put the car in gear. I had 2 of the (I believe) rubber differential mounts replaced, but still have a "click" noise when I let out the clutch. This noise is also in conjunction with a squeak noise that I have when driving. This squeak noise does not seem to increase with speed but is definitely from the rear.

Ted

T. Grant

Hi guys,
I had the same problem spring up last week, clicking sometimes sqeaking when first starting off. I thought it was a cracked diff mount because I had the same problem on my race car some years back. Well... monday a.m. on the way to work the car developed a vibration and two miles later a u-joint let go destroying the inner yoke and halfshaft yoke.Talk about a 5 a.m. wakeup call! If you suspect a ujoint at all go ahead and replace them. Lucky for me I had extras, and was back on the road 2 hours later.
If you move the rear just a little bit it can load or unload a u-joint enough to click.
Michael it sounds like your problem is a cracked mount however never assume that the u-joints were installed correctly. It is way too easy for those needles to get out of place when installing them. Good luck guys.
Mike Munson

Rick, Ted, Mike,
thanks to the reply. I will try the vise clamps to see what that does. I did replace the lower front and complete rear mounts when I did the u-joints but did not do the upper front because of the hassle and half hoping I had fixed the problem. No such luck..at least I did not have the sqeaking..that would drive me absolutely nuts. I forget exactly how I did it, but I was able to get the pry bar to put pressure on the right front mount and basically push up that end similiar to the direction it would take under load conditions, and I got the distinctive click sound. This weekend I will sneak into the garage and do the vise clamp thing. I'll just tell the wife I am looking for christmas lights. Thanks, Mike
Michael Parkhill

Mike M
You say move the rear a little. On or off the wheels?
A NOTE OF CAUTION ON REPLACING U-JOINTS:
I need help on the correct word here. When u-joints are replaced you need to "allign" (this word)the 2 u-joints to one another. If you look at the axle shaft assembly (this includes the prop shaft) it has a spline that mates the 2 pieces and at the end is where the u-joints go. The orientation of the "U" must be parallel to each other when reassembling (both horizontal or vertical). Someone help me with the correct wording here please. Mike P are yours alligned after replacement? Hey Jeff, Where are you at in your diagnosis? A comment: One would think the clicking sound would increase with speed if problem is a u-joint...Yes? Mike M., Ok let us know how you changed your u-joints in only 2 hours. Is there an easy way without having to drop the diff? I can see the axle flange yoke is only 4 bolts but what about the other end? I would appreciate an answer to this as I would like to (over the winter) have a look at these u-joints. All this talk about thumps and squeaks and clicks has got me thinking about a mouse in the rear end not doing his job.
Regards
Rick
Rick Crawford

Rick,
I don't know about the prop shaft, but the splines on the half axles can only come together one way. If you look at the actual splines, there is one section which is wider that acts like a key so that the two pieces only come together one way. By the way, if you are going through the hassle of replacing the u-joints on the half axles, it is a good time to pull the two halves apart, clean them, and apply new lube.I had a little bit of play with mine, which is typical, but after clean/lube, it tighten them up nice. I too want to know the secret of changing u-joints in 2 hours, those things never cooperate with me.
Mike
Michael Parkhill

OK here goes, the flanges on the half shaft were destroyed so I just replaced the flange that bolts to the rear and the half shaft (u-joint already in place). Actually it took less than an hour to do the swap after the car was up because 1. air tools 2. practice makes perfect & speed 3.rear disc brakes are easier and quicker to pull off than drums.(I know this is going to open up a can of worms)! 4.it is warm in the south and you can work faster when your fingers are not frozen.(65 deg. that day).I spent the rest of the time limping the car home.
I stated I heard clicking on starting off, after that I don't hear much,(monza exhaust).
I was talking about moving the rear with a pry bar.I would never recommend moving the car back and forth on the ground while your head is under the car in the tire path. The car could pop out of gear....get the picture?
Ditto on what Mike P. said about u-joint & halfshaft alignment.
Did I anwer all the questions? Just had a big lunch. zzzzzzzzzzzzzzzzzzzzzzzzzzzzz
Mike Munson

Now that I've been listening intently for about a week, I seem to be feeling it more than hearing it. I may hear something but more likely feeling it. It like to replace my diff mounts Rick. You said you'd let me know how to do it. Feel free to fire away when you get a chance. Jeff
Jeff Hall

Mike M, Mike P
I must admit that when I bought my 6 in pieces the rear axle shafts where assembled so did not actually mate the 2 pieces. Maybe I should of had a better look at these before putting on the frame (check u-joints, inner bearings, grease spline, etc.). I made the assumption (oops, sorry bad word) at the time that since they where pre-assembled that previous owner/restorer had delt with this. This is a lot easier task when you can work from above with no body in the way!!! As far as the prop shaft is concerned, I am sure it does not have a "key" on the spline so it can go on "out of allignment" (3 years ago so bear with me on this one). So you cheated eh Mike? Disc brakes on the rear?? I have heard and read an article on this. Bottom line for the rest of us drum heads is a total removal from the wheel inward to the 4 bolts of the inner axle flange. This is definitely not 2 HR job especially with numb fingers. One could say us NORTHERNERS have more time to work on our cars. At this point, it would probably be best for you foke out there to change over to polly bushes on the diff. and do examination of mounting points. When I read your reply Mike I interpreted the move rear end as physically moving the car, and yes I agree that NO you would not get the picture if tyre ran over hear...well... then maybe you would get to see the big picture:) I was thinking moving car by hand (a friends hands...a really good friend:). I wonder if the clicking can be heard if rear of car lifted off of ground and tyres rotated (by hand)?
Hey, car 54..I mean Jeff Hall..where are you?
Regards
Rick
Rick Crawford

Jeff,
If you are feeling the car move around when you take off(feels like a warped wheel), then it is more than likely a u-joint. Sometimes you can see rust around the grease seal on the bad u-joint.

Mike
Mike Munson

Jeff
what u say sounds like u-joint(s). I would not discount bearings so have a look at them.OK, here goes:
Jack rear up and put jack stands under both side trailing arms. Block front wheels. Remove muffler system from the connection of both pipes after the dual down pipes. Support the diff with a hydralic jack. Disconnect the drive shaft from the diff. 4 bolts and nyloc nuts.NOTE: when reinstalling any nyloc nut use new nuts and make sure the front and back u-joins of the drive shaft are aligned to one another---read previous entries this thread--the prop shaft can be put back (u-joints not aligned) together at the spline if seperated here. Disconnect the (both sides)axle flange yoke from its inner axle shaft flange--4 bolts 4 nyloc nuts. Remove 4 main nuts holding diff. in place. Drop the jack slowly and make sure the diff. does not get hung up and drop suddenly. If you raised the rear high enough the lowered jack should come out the rear end with the diff. on it. Remove the rubber bushes from the front studs if they stayed on the stud. Clean the seats of the bushes on the diff. Clean and spray paint the large washers as you will be reusing them. You may as well replace the diff. fluid since it is easier now. Check the breather hole on top of the diff. A cotter pin should be there--do not remove but instead move it about to make sure it still moves freely. You may wish to add (if your diff does not have and most likely does not) a drain plug at bottom of diff. This is another story and I will deal with that if you wish on another thread. OK so the diff. is out now and as you can see one can get at some,not all, of the bearings and u-joints of the complete rear end. So here you are at being able to change the rubber to poly bushes. As far as bearings and u-joints...well that is up to you to determine if change is needed. Keep in mind that if you are not sure of their condition, well your are more than half way there to doing the complete job. Read my earlier posting re us drum heads. Oh Ya, check the mounting points for cracks and wear. Having the diff. serviced is another story also. If the seal of the diff leaks now is a good time to replace. Reinstall using reverse procedure.WOW! only took 4 words to do that:) Grease the splines as this is also easily done now (including prop shaft).
Have fun Jeff
Regards
Rick
Rick Crawford

Are you sure this thread isn't tittled "out of balanced su carbs"? So many answers so little time.
DON KELLY

This thread was discussed between 17/12/2001 and 22/12/2001

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