An expensive sound comming from the rear end.....

[RobT]

Beautifull weekend weather here in New England, so I take the TR250 for a spin. About 5 miles down the road, a rather unplesant sound starts. Seems to be comming from the rear end, but its often hard to tell exactly given how sounds can transmit through the drivetrain.

Anyway, the grumble/gnashing only occurs under power, or braking on compression (rolling in neutral is quiet as a mouse).

Accelerating from a standstill there is also a repetative "clunk, clunk, clunk" - again seems to be the rear end. My guess is the differential is kaput.

Any way to be certain? Once I drop the diff, how can I tell?

TIA

Rob.

 

[brdave]

There are alot of U joints back there to check out first.
dave

 

[philknight]

Rob, I agree with Dave. 5 U joints back there and 1 below your parking brake. I'd give 5-1 odds it's a U joint. If you can hear a grinding noise it would be pretty much shot. It will be obvious once you jack it up and visably check it out if it is one of the joints.
Phil

 

[RobT]

Got the car jacked up. The U-joints all look fine - nothing obvious I can see. No slop or noise when I turn the wheels by hand.

Anything else I should look for in the u-joints?

Rob.

 

[Tinster]

Got the car still jacked up?
If it's on jack stands (for safety),
chock the front wheels, put the car in
neutral and rotate the driveshaft in both
directions by hand, while you are on your
back near the differential.

Try to listen and feel for sounds you are
hearing while driving.

d

 

[gjh2007]

Rob:

keep us posted, I can offer my own experience at dropping the diff if need be. If the worst should occur I have a spare diff you can borrow.

Can you get to Ipswich I can take a look at it with you over the weekend?

 

[Andrew Mace]

You'll need to actually lever on the yokes to see if there's play in a universal joint; by the time you can see or feel play there without leverage, you'll be thanking your lucky stars that it didn't just let go and cause much costly damage!

Oh, and don't discount the possibility that a FRONT wheel bearing is on the way out. Odd as that sounds, it's possible. Happened a couple years ago on my Herald. I thought for sure the noise was coming from the rear, and it occured under the same situations you described. Sure enough, it was a front wheel bearing!

 

[Brosky]

Re: An expensive sound comming from the rear end..

Andy, that is solid advice.

Rob, are you closer to Ipswich or Providence? Maybe Gary or I could help you check it out?

 

[Trevor Triumph]

The trouble with u-joints... I had a snap in the Spitfire drive line last spring. I took the axle off the car, mostly out of desperation, and discovered one finger of the u-joint was toast- dry powder, no grease. The other three appeared to be fine. I didn't know the condition until the axle was off the car and I could move the u-joint by hand. T.T.

 

[RobT]

Thanks guy's for the sage advice. Particular thanks to Gary and Paul. I PM'd you both.

I went ahead and dropped the diff over the weekend (actually pretty straight forward - even cleared the exhaust system without trauma). There is definately a "clunk" when I turn the input flange by hand - bad pinion or bearing?

I manipulated the u-joints I could get to by hand - the three thet connect to the diff. All seems good there. Of corse the ones nect to the hubs are impossible to get to so my next job may be to pull the half-shafts and hubs out (I know at least one of the splined half-axles needs rebuilding/replacing - so perhaps time for the Goodparts CV upgrade!)

I have a call in to John Esposito at Quantum Mechanics, hopeing he can walk ne through some diagnostics.

I'll keep you informed. Starting to feel suddenly poorer though.

Rob.

 

[Camping57]

I had a similar sound from my TR3 and it turned out that I had knocked two teeth off of the pinion. It only showed up on accel. and decel under load.
I ended up getting a rebuilt axle from TRF. By the time I priced out parts and because there was no one I could find locally that I trusted to set it up right it worked out to be a reasonable fix.

 

[gjh2007]

Rob:

With that beautiful 250 you have, you'll be glad you don't have mine with all the work it needs. Whatever you spend on it, it's worth while!

Hey, it's only money; (yours that is!!)

 

[YankeeTR]

A 'tight' u-joint will do a real number on your troubleshooting. It's pretty common in the 'big truck' world to have a u-joint seize up due to a lack of lubrication...it will 'seem' OK when you check for play but will make noise, vibrate and generally make cause a ruckus.

If in doubt, take all the joints apart and look at 'em...PITA I know...

 

[Deleted member 451]

I had a similar sound from my TR3 and it turned out that I had knocked two teeth off of the pinion. It only showed up on accel. and decel under load.
I ended up getting a rebuilt axle from TRF. By the time I priced out parts and because there was no one I could find locally that I trusted to set it up right it worked out to be a reasonable fix.

Had exactly the same thing happen to mine but just one tooth. $1400.00 when all was said and done.

 

[RobT]

You all had me hoping it was just a bad U-Joint, but I was not quite convinced. I knew I could not be that lucky. So I poped the rear cover off the diff last night, and look what came out (along with lots of glittery gear oil):

(And before some smart fellow asks, no - the Sharpie was not inside the diff, its just there to provide scale.)

I figured these little beauties shouldn't be floating around inside all by themselves. Sure enough they used to belong to the pinion gear:

I'm guessing super glue aint gonna fix this one! Off to the diff doctor it goes. Oh well, nothing time and money won't fix.

I was suprised the car was mobile at all with two missing pinion teeth! The diff on my brother's GT6 went once - the back wheels seized momentarialy, and then a piece of gear blew a whole in the caseing. Ouch.

Rob.

 

[pa297pass]

OUCH! /bcforum/images/%%GRAEMLIN_URL%%/cryin.gif

Those pictures are painful to look at Rob.

Good luck with your fix ... I'm sure you'll be back on the road soon.

Matt

 

[YankeeTR]

Same thing happened to my TR3A...150 miles from home...limped back without any problems except it would kinda 'catch' when accelerating from a stop.

You could find a used one and buy yourself some time or buy a R&P and fix it yourself...not too difficult despite all of the horror stories you may here from guys who have never done it.

 

[Brosky]

Re: An expensive sound comming from the rear end..

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]You could find a used one and buy yourself some time or buy a R&P and fix it yourself...not too difficult despite all of the horror stories you may here from guys who have never done it. [/QUOTE]

I'm not sure if I totally agree with that strategy. If you don't have the proper tools and knowledge to spread the case with out damaging anything and install the ring and pinion with the proper setting of the pinion depth and bearing preload, you can make a pile of junk out of new parts in short order.

If you have a helper, with the necessary tools and know how, fine. Other than that, remove the assembly and send it to a pro. You may be able to buy a used or recon unit for a reasonable price as well. I don't know how the broken teeth will affect the core value of the part for a reconditioned unit.

JMHO and I'm not trying to discourage anyone from learning about their car. I've just seen too many of these major projects go bad and the costs of repair double accordingly.

 

[YankeeTR]

Re: An expensive sound comming from the rear end..

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]You could find a used one and buy yourself some time or buy a R&P and fix it yourself...not too difficult despite all of the horror stories you may here from guys who have never done it.

I'm not sure if I totally agree with that strategy. If you don't have the proper tools and knowledge to spread the case with out damaging anything and install the ring and pinion with the proper setting of the pinion depth and bearing preload, you can make a pile of junk out of new parts in short order.

If you have a helper, with the necessary tools and know how, fine. Other than that, remove the assembly and send it to a pro. You may be able to buy a used or recon unit for a reasonable price as well. I don't know how the broken teeth will affect the core value of the part for a reconditioned unit.

JMHO and I'm not trying to discourage anyone from learning about their car. I've just seen too many of these major projects go bad and the costs of repair double accordingly. [/QUOTE]
Actually, I've never seen a case that needed that spreader that is shown in the repair manuals. everyone I've worked on simply came apart with only slight interference.

I used to do rear end repairs on 60's vintage GM cars while working at a dealership in the late 60's/early 70's and we never even had one of those tools.

When I did my TR3A, I simply removed the bearing caps and kept the shims seperated...I did the same with the pinion gear. I installed the new pinion with the old shims, and torqued it to specs. Then I installed the new ring gear using the same shims I took out...very easy and simple.

Then I did a very simple check for pinion depth and side load by using some white litihium grease spread onto the ring gear. I had my wife put some pressure in the ring gear with her hand (covered with a rag) and I gave the ring gear one revolution...a perfect wear pattern appeared.

I then filled it with lube and drove it another 8 or 9 years. the entire job, start to finish, took less than 8 hours...now I do have a lift but it's still pretty straightforward.

I worked in repair shops and dealership service departments for nine years. While some of the mechanics went by the book, most guys simply replaced the gears with new parts never ever checking side play or backlash. Assuming the new parts have the same close tolerances of the old parts, everything should go back together exactly the same. We did A LOT of rear ends in those days....a 9" Ford or an 8 3/4" MOPAR rear is a little tougher because you have the adjusters for the ring gear. But any type that simply uses shims is really easy to do.

This is one of those jobs that is 'black magic' to most guys...kinda like automatic transmissions. Once you've done one you realized how simple the job can be. My old friend Doug Bandl had a transmission shop and he once overhauled my MOPAR 904 transmission while I was out to lunch. I brought it into his shop, layed it on the teardown bench and left. I got back 90 minutes later and it was done! He used to always brag that he made $500.00 an hour doing what most guys could do themselves...

There is really nothing on these old TR's that any owner with a reasonable amount of tools can't do himself...that includes transmissions and differentials...We used to junk these cars beacuse the floorboards got rusty and look what we can do today with little help.

 

[Brosky]

Re: An expensive sound comming from the rear end..

Yank,

Like you, I came up in the dealerships of the 60's through the 90's. I just wasn't as lucky (or maybe as good!) as you. I can't tell you the number of 442 and Cutlass rear ends that gave me and the other guys fits. Not for getting the gear cases out, once you cracked the factory thick shims with a punch, a pry bar handled the removal easily. The problem came in pinion depth and shimming the side play. Sometimes you'd hit it just right and it was back together in no time. With other instances, the result was just the opposite. I watched one guy who refused to use a micrometer to measure shims (he trusted factory labels) smoke a ring and pinion on a 5 mile road test.

I have never had a TR6 differential apart on my own. I did see several being torn down and the cases all needed spreaders. If these don't require any special consideration for a collapsible spacer in the front of the pinion, that helps as well.

But you are correct, there is a black magic to all of these repairs for each of us. I loved rebuilding Holley & Quadrajet carbs, other guys hated them and would do what I hated (upholstery & front suspension) as a swap.

My days of doing that heavy work are over now. Well, that is if I want to be able to drive the car in the next few weeks after working on it.

But I will be directly assisting on the tri-carb swap next week!