[TR] OD transmission

[Randall]

Definitely not normal.  The OD should shift positively at any engine power and gear (except 1st & reverse of course); and not drop
out unless you flip the switch, turn off the key, or shift out of gear.
 
>From your description, I'd guess the OD hydraulic pressure is drastically low.  Buy or build a pressure gauge (there is a special
adapter required) and check the reading.  Unfortunately, you'll need to pull the tunnel, but the good news is that the OD doesn't
have to come out of the car to check the pressure.
 
BTW, if I am right, then the OD clutch is slipping when it appears to drop out of gear, and may even be slipping a little when you
don't notice.  It's probably best not to use the OD until you can correct the problem.
 
 
-- Randall 
 


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From: Triumphs [mailto:triumphs-bounces at autox.team.net] On Behalf Of Rye Livingston
Sent: Tuesday, October 06, 2015 8:54 AM
To: fot at autox.team.net
Cc: triumphs at autox.team.net
Subject: [TR] OD transmission


Looking for comments and suggestions. 

I just installed a TR4 rebuilt overdrive transmission in my 1960 TR3.  Everything is running well and the OD is pretty cool.  I
don't know what to expect or how it should work, but this doesn't seem right to me.  When I'm up to 60 mph or so and flip the
switch, it shifts into OD no problem.  If I'm accelerating at the time, it won't shift until I let up on the gas so there isn't any
load.  As I experimented with this, driving down HWY 1 along the Pacific Coast Highway, there are short rolling hills and as I am
going up the hill and flip the switch, it won't shift into OD until again I've crested the hill and have let up on the gas a bit.

Now 3rd gear, I wondered if I'd ever use OD in 3rd gear, but I do find when driving along a 4 lane blvd with the speed about 45 mph,
3rd gear with OD is pretty nice.  So while cruising along like that when I accelerate fairly aggressively, like an automatic
transmission, without me touching the switch, it will drop out of OD by itself as I accelerate, and when the load is reduced as I
let up on the gas, it will shift back into OD.

I told the mechanic who rebuilt the transmission about this and he said that isn't right, and his first question was if the oil
level OK so I checked.  I took out the side fill plug and can see the oil level and it just starts to ooze over the threads. So
that's not the problem.

What is normal shifting for an OD transmission?

Thanks,

Rye

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