Driving--Overdrive

[KVH]

Now that I've adjusted mine a third time (hopefully it holds), I thought I'd ask about driving. Is the OD only for the highway after fourth gear or is it proper to drive in other gears in OD?

When does it automatically disengage? Just going back to first or second?

Finally, is there a "gentle" way to drive and operate in OD?

 

[TR4nut]

Well, they designed it for you to use it in 2nd through 4th, but for me I must say I really only kick it in on the highway when I'm in 4th. I did try it on some twisty mountain roads this past spring, more to upshift/downshift via the overdrive than go through all the gears.

Everybody has their preferred way I guess, but in my TR4, I basically clutch when I engage the overdrive as I'm accelerating from 4th. Makes it basically like a 5th gear change without any jolt.

 

[TR3driver]

Depends on your driving style and what you are doing, IMO. For casual driving, I mostly only use 4th OD as a 5th gear. But if you are trying to get up to speed in a hurry, using 2nd OD will shave a few tenths off your 0-60 time. 3rd OD can be handy sometimes on twisty roads, but otherwise I don't use it much.

The OD should drop out in 1st (not 2nd), but remember it will try to re-engage as soon as you hit 2nd gear, which probably isn't what you want.

To be "gentle", always depress the clutch when shifting the OD, then release slowly just like you had shifted to a new gear.

 

[Geo Hahn]

You may find the 3rd gear OD very useful when you're driving up Mt Lemmon.

Depending on how traffic is moving it can be hard to hold 4th gear when climbing 5500' in 19 miles but 3rd gear feels a bit short -- 3OD is nice.

<span style="font-style: italic">BTW -- For some Tucson drivers today was our 100/100 event where we cover 100 miles in 100°. In all the years we've run this we've never had a car breakdown en route (had one MG not make it out of the parking lot last year) and this year was no exception (though an AC Ace did pause along the road to contemplate for a moment).</span>

 

[TR3driver]

<span style="font-style: italic">BTW -- For some Tucson drivers today was our 100/100 event where we cover 100 miles in 100°. In all the years we've run this we've never had a car breakdown en route (had one MG not make it out of the parking lot last year) and this year was no exception (though an AC Ace did pause along the road to contemplate for a moment).</span>

These days, I worry more about the driver than the car! We did our own "100/100" a couple of weeks ago (coming home from watching the Perseid shower out in the Mohave) and it about did me in! But the TR3 never got hotter than where the fan kicks on (and then only when we were stopped or moving slowly).

 

[TRTEL]

Completely agree on use of the clutch, it will save you money in the long run. Can't recommend using the A units in 3's and 4's with second gear unless the unit has been upgraded with Healey springs, etc.
Tom Lains

 

[tdskip]

Flicking in/out of OD in 3rd can be great fun on the right road. I wouldn't be afraid to use it.

 

[airlifter]

When driving on the Blue Ridge Parkway I usually use 3rd gear and shift in and out of OD. I have not been using the clutch when shifting in out of OD. Maybe I should???

 

[airlifter]

I am having a similar problem with my TR6. When I let the clutch out it seems to bind and will not engage smoothly. I have the car on jacks now while I am working on the brakes so I will check how the slave cylinder is mounted.

 

[TR3driver]

Maybe I should???

A matter of opinion and personal style, IMO. The unit was clearly designed to shift under power IMO, but there is a certain amount of wear and tear associated with doing so, both on the unit and on the rest of the drive line (especially the IRS cars with the weak differential mounts).

I don't like the big clunk I get when shifting into OD under light throttle, so I always use the clutch for that. But downshifting under almost any condition, and upshifting with heavy throttle are nice and smooth, so I rarely use the clutch then.

But I have managed to tear up a couple of ODs in 35+ years and 300,000+ miles; so I won't claim to have the last word on the topic. For those who want to "restore" their cars and then never touch them again, it is probably best to always use the clutch. My personal philosophy is closer to "Drive it hard until it breaks, then fix it and drive some more."

This is from an AH ad, but the OD unit is basically the same:

 

[JerryVV]

Nothing quite like a full throttle switch into OD while wound tight in second gear. The car leaps forward. Fun to do on occasion when some dude with a coffee can tailpipe is pestering you. Even surprised me the first time.

 

[TRMark]

Maybe I should???

A matter of opinion and personal style, IMO. The unit was clearly designed to shift under power IMO, but there is a certain amount of wear and tear associated with doing so, both on the unit and on the rest of the drive line (especially the IRS cars with the weak differential mounts).

I don't like the big clunk I get when shifting into OD under light throttle, so I always use the clutch for that. But downshifting under almost any condition, and upshifting with heavy throttle are nice and smooth, so I rarely use the clutch then.

But I have managed to tear up a couple of ODs in 35+ years and 300,000+ miles; so I won't claim to have the last word on the topic. For those who want to "restore" their cars and then never touch them again, it is probably best to always use the clutch. My personal philosophy is closer to "Drive it hard until it breaks, then fix it and drive some more."

This is from an AH ad, but the OD unit is basically the same:

Exactly how I drive mine. I use the clutch when shifting into OD when cruising. When it is time to pass I use it like the A-H ad describes.

 

[Member 10617]

Related question:

For the most part, I avoid highways. Because of the narrow, twisting, back-country roads that I normally drive, I rarely use my OD. But a car friend of mine once told me that I need to engage the OD from time to time in order to keep it well lubricated and in good running order.

Does that sound right? What if I never used the OD?

 

[rlich8]

I always use the clutch in and out of overdrive, just as if it were another gear on the gearshift. Forget about what manuals say and what granddad did years ago, these cars need a little finesse and using the clutch pedal doesn't hurt.

 

[JerryVV]

The OD will get plenty of lubrication even if never used. The only issue might be sediment collecting in the pump but I doubt that too.

 

[Member 10617]

Jerry,

I thought as much.

Thanks.

 

[Geo Hahn]

It's been 6 years but the memory of wrassling that OD into place working alone is fresh enough that I will use the clutch when switching in & out. That's one job I would be happy not to have to do again.

 

[JerryVV]

Geo, I agree but sometimes it's just what you have to do. Like on the Tail of the Dragon or Route 60 in Northern GA. You just have to do it.

Last few times I invited some friends to help with beer and 30+ years of friendship. I've done it myself in my younger years but not now. I suppose I could get it out OK but back in is another story. Frankly it would be easier to pull the engine and trans as a unit myself than just the gearbox. That's on a 4A, with a 3 it's not fun doing that either.

JVV

 

[TR3driver]

The OD will get plenty of lubrication even if never used. The only issue might be sediment collecting in the pump but I doubt that too.

Even that doesn't make any sense, as the pump runs all the time whether the OD is engaged or not. Even the accumulator piston gets exercised, since the pressure will bleed off with the car stopped, and build up as you drive until the piston uncovers the relief slots (again whether the OD is engaged or not).

For an A-type of course. Other models work somewhat differently (but should still have no problem with not being used).

 

[JerryVV]

Sorry I didn't make any sense