I used to have a couple of British sports cars back in the '70 and early '80. The Triumphs had OD that was available in 3rd or 4th gear depending on what you needed. It was great to get into a street race with a Fiat and watch the look on their face when you shifted into " 6th" gear !!!!

Anyone every wire a Volvo to have the 3OD ? All I can figure is they have too much torque for the OD to handle compared to the anemic Brits.
--
In Tacoma '86 245 200K+ and '86 740T- 215K+ both with M46

I remember reading somewhere that if you happened to enable the OD in reverse that severe damage would occur to the Laycock overdrive unit... just passing on what I heard, not what I know.

Randy

Well, the OD goes in one direction...

Reverse ain't it.

1st gear = 3.71 or 4.03
2nd gear = 2.16
3rd gear = 1.37
4th gear = 1.00
Overdrive = .79

3rd + OD = 1.37 * .79 = 1.08 gear ratio ... hardly enough of a difference over the 1:1 ratio of 4th gear.

-- Kane
--

While I would never deliberately mislead anyone, take into consideration that any info and advice was provided at no cost to you.

I was wondering about the ratios, Kane. Thanks for posting them.

So shifting from 3rd+OD to 4th would actually be a down-shift.

To shift it like a 6-speed, you'd go: 1st, 2nd, 3rd, 4th, 3rd+OD, 4th+OD. With almost no noticable difference between the 4-to-3+OD shift.

jp
--
'93 945 Turbo (201K miles), '93 945 (140K miles/I maintain for a family member), '93 945 Turbo (sold w 145K miles), '92 Mercedes 190E (174K miles), '85 Jeep CJ-7 w/ Fisher plow (225K miles), '53 Willys Overland w/ Fisher plow (sold to a loving home)

There is a switch on the tranny that allows the o/d solenoid to operate only when the tranny is in 4th gear.

If that switch was by-passed, one could have o/d in ALL gears, a potentially dangerous situation. With care though, one could enjoy that o/d in 3rd and 4th you describe.

Regards,

Bob

:>)

I wired my OD to come on for all gears and just have to be careful so I dont reverse in OD. There is little difference in 3+OD however 1st+OD and 2+OD helps in city "moron mode" driving during rush hour. Now the only thing I have noticed with reverse is if the OD is left on the Laycock will chatter and the car wont move much, I have not seen any damage however. The other issue is with leaving OD on and starting from 1st gear. Given its a piston on an eccentric from the trans output shaft it takes a certain speed to get enough hydraulic pressure to engage the OD piston, during hard acceleration and forgetting I had OD on the car will "bark" the tires during the shift over similar to an automatic transmission but much harder. I dont know what damage is done but I wouldnt advise driving like that. The last issue I have is when I forget OD on and stopped at a hill and allow the car to creep backwards. It seems as if the OD has a pressure reserve and holds the piston down in the OD position, allow the car to creep backwards even a slight bit lets you know that its still engaged along with the guys around you with the sharp driveline "PING!" when the torque is suddenly released.

Just some observations from experience but again I dont know what the long term effects are from abuse, if not abused I see no reason not to use OD in the other gears as it does have the effect of a "dual range" that can be quite handy in city traffic or very slow loitering around town.

Brandon