Thread: Some contemplations on overdrive

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I have had a Few GM's with the OD Transmissions . What I can Say I did not Like is . When your at Low Speeds 35-40 and it goes into OD . The Car will Lug and the RPM's go to a real Dead spot . Now on car's with 3.23 or Larger Gear gears Like the 1988 F-Body 3.27 Gear and 1987 442 3.73 Gear . They would go into OD at 30-32 MPH and what it felt Like to me was that the Rear end was trying to push the car . Making it even slightly harder to stop fast at that speed . Now this would be more of a Problem on a Car Like Mine that was driven more in the City then the Highway . My Friends that run these OD Trans Build's use a Switch under the dash to Lock out the OD When they are Driven in the City . Yes you could Shift down into 3rd But on my Pick up with the 700R-4 the Lock up Converter jumps in and out at 35 MPR . I said the heck with that and Un-Pluged that Trans Plug . It works Great Around Town now . Yes when your over 50 MPH They are Great . And you can get unreal Power off the Line and Top end . That 442 with the OD and 3.73 Gear Felt Like it never ran out of the Right gear .

If it Dead Hooks that trans Could be Dust

Originally Posted by tango

If it Dead Hooks that trans Could be Dust

Not yet!!!! But with just 100 more ft. lbs. torque it would have to be a G-Force 5 speed instead of a Tremec with hardened shafts and gears!!!! (It's all in the clutch! If I were to put the old McCleod dual disc in it doubt it would live for half a dozen launches!!!!!)

Ya I have Taken Car's Of the Line with M22 4-Speeds and 4.10 Gears at 5 Grand . Man you Should have seen the Folks Running to get out of the Street

The new dual friction clutches help a lot to take out some of that initial driveline shock, especially in a well prepped chassis with slicks. Drag race only, then I use the McCleod Soft Lok....

PS--used to launch my old mini motor Maverick at 6500 and shift at 7200 with a 10.5" wide Hoosier slick!!!!! Most fun you could possibly have with your clothes on!!!!!

I ran that Borg and Beck 3 Finger Clutch set up . Yes it was hard to push Down and when you Dumped the Clutch it was very Violent all the way to the back tires . My 1965 Mustang has some Hays Clutch I can Hardly Push it Down . I know I am getting Old I will have to install a Newer Type in there .

when i get enough cash im definaly looking into a g-force 4 speed!!!!!! dave showed me them boys from g-force and now i want one !!!!

Hey Scooter I knew you could not stay Clear of any 4-Speed beat on your Car Threads

Scooter You want to Launch your Nova Like This ?

thats a bad chassis set up if i ever saw one haha. no i want to keep it wheels down just shit n get , you know me if its a stick my nose is in it learning!

a transmission is more efficient when running direct in the top gear.... but what ratio would the transmission gear sets be? I'm not saying you're wrong, just gave the example of why I like the 5 and 6 speed transmissions....

Originally Posted by Dave Severson

a transmission is more efficient when running direct in the top gear.... but what ratio would the transmission gear sets be? I'm not saying you're wrong, just gave the example of why I like the 5 and 6 speed transmissions....

The ratios would be whatever is optimal for the desired application. A drag car would be different that tow truck.
Actually it looks like the Richmond transmission attempts to do just that, allow you to tailor the ratios you want in conjunction to a 1:1 5th.

Ok, but then to equal the same overall ratio that my 5 speed has with a 4.11 rear gear, wouldn't the low tranny gear have to be so high numerically that the car would only move a few feet before shifting??

My point is, without the overdrive gear (or gears with the 6 speed) how could I still enjoy my car in the "best of both world" environment that my 4.11 rear end gear and .62 overdrive trans gear????

[QUOTE=Dave Severson;339271]Ok, but then to equal the same overall ratio that my 5 speed has with a 4.11 rear gear, wouldn't the low tranny gear have to be so high numerically that the car would only move a few feet before shifting??

My point is, without the overdrive gear (or gears with the 6 speed) how could I still enjoy my car in the "best of both world" environment that my 4.11 rear end gear and .62 overdrive trans gear????[/QUOTE
I just wrote about 2 paragraphs with examples and deleted the whole thing, if you don't understand that the total (transmission ratio and rear end ratio added together) ratio in any given gear would not change then I give up trying to explain it. It's giving me a head ache

An example of what Willowbilly is saying , My cousin has a Kenworth with a 425 Cat and 15 over trans., 4.11 gears. My Eagle has a 425 Cat and 15 direct, 3.55 gears. RPM at 60 mph is 1750 in both. Speeds in all gears is the same. The OD trans is a bit noisier in top gear, and the direct geared one seems to pull a hill better in top gear. On a long uphill grind, the Kenworth can go down to Direct and pull like crazy, quieter than the IHC in 14th (reduced gear). Once you shift them both down below that, there's no difference. Neither gets more than 5-6 MPG grossing 120,000 lbs, so I can't say if the reduced friction makes any difference in fuel consumption. Logic would say it should, but a few percent at that high rate would be awful hard to detect.