That was my first thought as well, but Gary beat me to it.
John
On Mon, 11 Sep 2017 16:59:16 +0000 (UTC), Gary Schneider via Fot wrote:
Tim,
Are you sure its the diff not the trans? One more thing to look at only if you
have an overdrive - my overdrive caused exactly that symptom once when the
actuator pressure didn't leak down properly due to swarf in the tiny bleed
passage. It stuck in overdrive which caused the one-way-forward over-ride
clutch to engage. The driveshaft then refused to rotate in reverse. It rotated
forward freely but was capable of holding off considerable reverse torque as it
drove the small rollers up their ramps tighter against the clutch. Problem
would go away in a few minutes as the oil bled down.
The same could also happen if the OD lever is a little off and the OD valve is
constantly engaged with the solenoid off.
If the car's in the air you can run the engine to build pressure and manually
toggle the overdrive lever to assure it clunks in and clunks out.
Hope that helps.
Gary Schneider
From: timmmurphh--- via Fot <fot at autox.team.net>
To: fot at autox.team.net
Sent: Monday, September 11, 2017 10:11 AM
Subject: [Fot] Urgent! TR4 Detroit Locker problem, locks wheels going backwards
We have a race this weekend at Elkhart Lake. Just put engine/trans back in car.
Test drove on road. In trying to backup, both rear wheels are locked solid.
Trying to reverse just stalls engine.
Last time the car was on the road was in May at Gingerman. No problems. Since
then been sitting up in the air on the lift getting ?air time? while new block
being machined.
Very puzzling how sitting up in the air would cause diff problem. Car now has
more ?air time? on the lift than track time!
Have taken cover off diff, everything looks okay. No pieces of metal. Gear oil
pretty black, has been in there about 10 years.
Both ring and pinion look okay.
Put fresh Reline gear oil in and buttoned up.
Tried again on lift.
Turning drive shaft (trans in neutral), can turn both forward and backward.
Both wheels turn.
Try in driveway, same result, cannot backup, trying just stalls engine.
We could get the car back on the lift by driving forward and turning around in
the cul-de-sac by the house. Did donuts in the cul-de-sac to see how diff
reacted. Left two nice black marks in the donut. Accelerated forward and the
diff was unlocked because there is just one long black streak. I?ll have to ask
Ryan how it sounded and acted. He was driving to do that.
When car back on lift, same thing, both rear wheels locked up when trying to
turn backwards last night.
We can make diff lock and unlock by holding one wheel and turning the other
wheel forward. Not sure about specifics, wasn?t taking notes.
So far, we can make it work, sometimes on the lift, by turning the driveshaft.
But once on the ground we cannot make if work under power. We could push the
car backwards out of the shop but once we drove forward and tried to back up
the wheels were again locked.
Any insight or suggestions will be much appreciated. Is this a typical failure
mode for a Detroit Locker? Any suggestions for further examination and testing?
The last time we drove the car back into the shop to put up on the lift we
heard a pretty loud ?clicking? noise from the diff. Never noticed this before
but wasn?t necessarily listening for it before either.
Very interesting, I just tried turning the wheels with car on lift and can turn
both wheels, individually, both forward and backward, no problem. It is now not
locked up in the backwards direction. When turning one side the other side also
turns in the same direction. It?s acting like the diff is locked up in both
directions and the wheels turn in both directions. Last night, the last time we
tried turning the wheels backwards it was locked up. Maybe it only works up in
the air!!!!
Very puzzling!! I am not at all familiar with how the Detroit Locker works. It
was the one thing on the car we never had to worry about. I guess I?ll learn
something now?
Tim and Ryan Murphy
Murphy?s Law Racing (very appropriate today!)
1961 TR4 #317 BRG
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