Noisy Diff.

[GT6Don]

Hi

1980 Sprint makes a rumbling noise on the overun. Had a look and the internals seem ok, albeit, there wasn't too much oil that came out. Turning the pinion end has some roughness.
There may be a, linked, problem with the propshaft that I replaced about 400 miles ago; this was made for me by Bailey Morris in Cambs. On inspecting this prop, we found that the free sliding movement seemed to be very short: 10-15mm.
Is this all normal Sprint stuff?

[Richard the old one]

I found that one of my prop shafts did not have much movement and this was caused by having too much grease pumped into it. When I removed the grease nipple and pressed the sliding section in it forced the excess grease out of the hole and this allowed full movement of the sliding joint. See attached photo

[Carledo]

If the prop is the standard Sprint design, with a CV joint/slider in the centre, the plunge IS very short compared to a traditional style UJ and slider.

A rumble on overrun is not a common Sprint diff noise (though it DOES happen) But it's my experience thar Sprint diffs often have noises and backlash that seem pretty nasty to folks used to modern manufacturing tolerances, yet they'll keep going like this for years.

Steve

[cliftyhanger]

Hi

1980 Sprint makes a rumbling noise on the overun. Had a look and the internals seem ok, albeit, there wasn't too much oil that came out. Turning the pinion end has some roughness.
There may be a, linked, problem with the propshaft that I replaced about 400 miles ago; this was made for me by Bailey Morris in Cambs. On inspecting this prop, we found that the free sliding movement seemed to be very short: 10-15mm.
Is this all normal Sprint stuff?

The roughness when turning worries me, but then again it is always difficult to interpret other peoples descriptions. If it feels like a bearing, that could well be the issue. And would need fixing before it fails spectacularly.
Vibration on over run can also be a prop UJ, so do not discount the prop just because it is new.

[Carledo]

As an add on, I also run all my Sprint diffs on 85/140 EP oil and ensure they are kept full. It doesn't shut up a very noisy diff entirely, but it does seem to help a bit. Sort of like liquid sawdust

It's also my experience that overdoing polybushing can make make diff noise twice as noisy. I NEVER (except the first time) polybush both ends of either trailing arms or rear tie bars for this specific reason. Dont know if your car is polybushed or not, just making the point!

Clive makes a good point above about bearing failure and rapid destuction. But again, it's my experience that a diff that's gone that far is already a boat anchor, it's still easier and cheaper to fit another used axle than to fix an existing but badly damaged one. With the increasing scarcity (in some cases, unobtanium status) of diff internal parts this can only get worse, besides adding an unpredictable/unacceptable time factor to any diff rebuild. And unlike the smaller engined models, the Sprint axle IS a whole unit, the diff has to to be built into the case by someone who knows what they are doing, it's not like the 1 hour of remove prop and shafts, undo a ring of bolts and pull the entire differential assembly of a 1500/1850 that anyone with a handful of spanners can do!

Steve

[GT6Don]

We drained out what oil there was and fitted a new pan gasket and filled up with oil and molyslip. Seems a lot quieter but after 10 miles or so it rumbles again. I'm torn between finding a replacement or getting my one repaired. The stiffness on turning the pinion is quite tight at one point. I don't suppose there is an easy was to replace that bearing?

[Carledo]

We drained out what oil there was and fitted a new pan gasket and filled up with oil and molyslip. Seems a lot quieter but after 10 miles or so it rumbles again. I'm torn between finding a replacement or getting my one repaired. The stiffness on turning the pinion is quite tight at one point. I don't suppose there is an easy was to replace that bearing?

Basically NO! The pinion shaft and it's carrier bearings are the last bits that are removed when the axle is dismantled and there are all sorts of preloads and shimming to do to rebuild and set up after a simple 4 bearing change. Like I said, no job for a amateur, or even a competent professional like myself with 50 years in the trade, if it comes to that! I farm out diff work to specialists, a man should always know his limitations (Clint Eastwood)

There's also the fact that the crushable spacer (single use only) in the Sprint's pinion setup is now effectively made of unobtanium. There are practical workarounds but still.....

If I was in your shoes, i'd obtain and fit a half decent used axle, then, if you want to tear yours down with a view to rebuilding it (or getting it rebuilt) at any time in the future you can do so without having the car off the road for an extended period.

Steve

[sprint95m]

I think I bought a single use spacer from Rimmers a few years ago Steve.
A quick scan of their website didn’t show anything but it would be prudent to use the part number…?

Am I now a millionaire?


Ian

[GT6Don]

Hhmmm. Well, my Winter Fuel payment has just fluttered through the letter box and it's £500 this year. That can go to the diff replacement. Anyone got a quiet, non-leaking axle/diff?

[PaulB]

The collapsible spacer part number is 156903 and it is still available.

[marshman]

I think I bought a single use spacer from Rimmers a few years ago Steve.
A quick scan of their website didn’t show anything but it would be prudent to use the part number…?

Am I now a millionaire?


Ian

It is on their website:

https://rimmerbros.com/Item--i-156903

[sprint95m]

Thanks folks,
I knew I wasn't haivering


Ian