• Hi Guest! Being a Paying Supporter is NOT a requirement to participate at BCF. However, subscribing will help ensure we can continue to serve the LBC community for years to come. If you enjoy BCF and find our forum a useful resource...Please consider supporting us by **Upgrading**
    (PS: Subscribers don't see this banner)

Rear Differential - Pinion Gear?


Jedi Warrior
Country flag
PO history and evidence suggests my particular AH BJ-7 had a difficult life. Here's a summary on the undercarrage: Front engine and trans mounts sheared/broken; rear shock mounts completely separated from frame, broken rear spring(s)/shackles, bent front frame rail (right side).

All of this has been identified, repaired and/or replaced during restoration. One of the things that I have yet to check, probably due to it's complexity, is the rear differential.

The pinion seal was replaced and yolk readisleeved; hub bearings and seals replaced and do not leak; driveshaft repaired and balanced.

Differential are fairly robust units but what would be symptomatic of something wrong? For example, a bent pinion gear or axle?

Suggestions would be appreciated before I take it into the shop for further assessment. GONZO

Skip & Lynne

Jedi Warrior
Gonzo you have answered my long burning question. What car had a head on collision with mine YOURS. Seriously if there is no vibration or leakage fron the pinion seal or yoke and the rear end is quiet I wouldn`t suspect any problems. Skip


Jedi Warrior
Country flag
Skip, that's it! Attempts have been made to isolate source(s) of intermittent vibration at speed. The usual suspects like wire wheels, tires, shocks etc. were sorted early on but that vibration still remains at 55 to 65MPH. Someone else in this forum summed it up nicely as "waiting for the shake" - quite true fo the Healey but maybe maybe it was a reference to living in California.

I understand that Scuttle Shake is common to the vehicle and this may well be the cause; however, the differential may be also contributing. How could this be isolated and checked?

Evidence suggest this Healey was dropped off some sort of embankment or cliff to only land safely on all fours, like a cat. This little mishap though managed to push the undercarrage up with such force as to cause the damage described.

This Healey is driven regardless of the vibration. My wish is for it to drive as good as it looks! GONZO

Dave Russell

Yoda - R.I.P

A solid big Healey with straight wheels & tires that are correctly balanced does NOT have scuttle shake. It is NOT common. A sometimes overlooked problem is brake drum balance, this has been a big problem on a few cars. A bent or out of index drive shaft can also cause shake.

To check for a bent axle housing, remove the entire differential center section, completely replace hubs & axles & visually check the alignment of the two inner axle stubs. They should obviously be centered with each other & in the center of the housing. Any misalignmemt indicates a bent axle shaft or axle housing. Rotating the axles individually will check for bent axles. A bent housing CAN be corrected.

A bent ring or pinion will make itself obvious in other ways, long before it could cause scuttle shake.

Shocks that are not in perfect working order can contribute to vibration. Any free play between the suspension member & immediate damping resistance of the shock hydraulics will allow for uncontrolled vibration of the wheel. If there is any lost motion in the shock links or dead spots in the hydraulic travel, vibration will be increased.

A few cars which have unrestored or improperly restored rust damage in the frame/subchassis will obviously shake more easily than a solid car. A problem sometimes arises when severely rusted structural parts are sand blasted & repainted. The paint does not replace the rusted metal, so structurally, the metal is still thinner than original & the chassis is more flexible. I have seen photos of "restored floor & structural sections" which obviously show deep cleaned out & painted over rust pits. These sections have no more strength than the thinnest rust sections, even if they look good. Sorry for the rant on "cosmetic only" chassis restoration. I have driven several new Healeys & a few "restored" ones. The truly restored ones, as well as the new ones, have no vibration at any speed. A couple of the clean & paint variety are remarkably flexible & vibration prone. Almost as bad as a TR6. Not all "restored" Healeys are the same, though the asking prices are often similar.
Similar threads
Thread starter Title Forum Replies Date
J TR6 Differential / Rear Axle Triumph 1
edkap2002 TR6 differential mounts, rear springs and shocks Triumph 1
J For Sale Triumph TR3 rear differential and rear brake assembly - Northern Illinois Triumph Classifieds 1
Lin Rear differential drain plug leak Austin Healey 16
P MGB Noisy Rear Axle / Differential MG 1
D TR2/3/3A rear shelf differential dome Triumph 9
KVH TR4/4A Removing Rear Differential Seal--Solid Axle Triumph 1
Got_All_4 TR2/3/3A Tr3 rear differential seal Triumph 7
KVH General TR Rear Differential Seal Triumph 7
C TR2/3/3A Rear differential Triumph 29
A Rear Differential Concern??? Triumph 11
T Spitfire Spitfire differential rear bushings Triumph 5
KVH TR4/4A TR4A IRS Front and Rear Differential Bridge Pins Triumph 6
J Rear Axle/Differential Gear Oil Spridgets 13
zschicago Replace rear differential gasket? Austin Healey 12
R MGB MGB Tube Type rear differential MG 0
R use redline mt-90 in 1275 rear differential? Spridgets 3
N Differential and rear suspension Austin Healey 113
I rear axle to differential flange bolt grade? Triumph 8
N Rear Differential Rebuild Triumph 9
KVH Rear Differential Overflow Valve Triumph 3
Lin Rear Differential bearings Austin Healey 2
C TR2/3/3A Broken TR3 rear differential Triumph 9
jerrybny Differential/Rear Axle Gaiter question Triumph 6
Healey Nut Rear Wiring Routing Austin Healey 2
R TR6 Rear suspension droop restraint Triumph 0
E GT6 Triumph GT6 MKIII rear hatch springs Triumph 2
drooartz Rebuilding rear axle Spridgets 10
S TR2/3/3A rear main seal is leaking Triumph 13
J TR2/3/3A TR3 Rear seat Triumph 11
T crankshaft (rear) bearing leak Spridgets 2
G For Sale: Triumph TR2, TR3, TR3A, TR3B Factory Steel Hardtop, New Rear window, Partial Bracket Set Triumph Classifieds 2
C TR4/4A Advice for grafting TR6 frame front to TR4A frame rear Triumph 14
5 TR2/3/3A Seized rear brakes Triumph 9
fpstude TR4/4A Replacing Rear Flexible Brake Hoses on TR4A w/ IRS Triumph 11
M TR2/3/3A Difficulty Adjusting Tr3A Rear Brakes Triumph 12
chicken BJ7 Rear Number Plate Mounting Austin Healey 3
Healey Nut Rear Wheel Cylinder Mounting Austin Healey 4
S Rear Wing Fit Austin Healey 4
chicken BJ7 Rear Quarter Panels Austin Healey 3
M For sale rear wings Tr6 Triumph Classifieds 3
Healey Nut BT7 Rear Suspension Austin Healey 15
FlyingCat Wanted 1980 Spitfire Rear Bumper Triumph Classifieds 2
M Have a pair of tr6 rear wings Triumph Classifieds 0
D MGB Rear Suspension Damper Link Arm MG 2
S Rear End Noises Spridgets 11
Jeepster Rear Brakes Adjustment Austin Healey 6
M Wanted TR6 Rear Bumper impact Brackets Triumph Classifieds 0
M TR2/3/3A Speedy Sleeve Repair Sleeves for Rear Axle Pinion and Half Shafts Triumph 1
E TR6 74 TR6 - Rear and windshield frame color Triumph 2

Similar threads