Overdrive transmission

[Dino]

Is there an auto with overdrive that fits in a 69 Charger with 440, that does not require tunnels mods? I expect to fabricate or customize a trans crossmember and find a driveshaft, but I really don't want to mess with the floor. I prefer electronic control so I can use a US Shift Quick 4 and not have to worry about kickdown linkage. I don't care if it's a mopar trans or not, as long as it can handle the torque.

[Mopar Nut]

Check out Silver Sport Transmissions.

[moparguy01]

The best bet for no tunnel mods is a gearvendors. Its a pretty slick setup

[Mopar Nut]

https://www.shiftsst.com/a41-automatic-4-speed-kit-for-for-1966-1970-mopar-b-body/p199


 

[armor64]

I've been waffling on either a gearvendors overdrive or a41 SST transmission for a year now. My 727 has the leakdown overnight, and a slight drip from the front seal that i plan to address, but there are good and bad for both... would be interested to hear more about others choices too.

[Mike DC]

The common retrofit kits use a GM 4L60E, which is the electronic version of a 700-R4. 

Basically, the kits are taking a smallblock GM tranny and giving it enough aftermarket beef-up parts to survive behind a big block.  You can't use a big block GM overdrive tranny because it wouldn't fit without floor/tunnel mods (just like the overdrive Mopar trannys).

Even with beef-ups the 700 still has a poor reputation for strength.  But the reinforced retofit kits seem to be producing satisfied customers for street cruisers. 


Opinion: 
I haven't tried it, but Art Carr sells an aftermarket kit for a GM 200-4R transmission instead of a 700-R4.  On paper it seems like a better choice than the 700.  Better gear ratio spacing and very lightweight internals. 

 
 
Any conversation about the strength of drivetrain parts . . . it's worthless unless everybody is very clear about where the goalposts are.

Goalpost #1 - what kind of usage are we talking?
"Stock 440 engine blocks?  Oh take it from me, those things are junk.  Don't waste your money.  They break the first time you hit them with 1000 hp."     

Goalpost #2 - what has been done to stuff?
GM 2spd Powerglides were originally made for crappy little smog motors.   But there are aftermarket ones that tolerate 1500 hp all day long.   

[Charger_Dart]

I have been running a Keisler (pre SST) 4L60E behind my 500ci engine for 13 years now. I have had zero issues with this transmission and I love it on the highway - 4th gear and a lockup converter are awesome. I did not have to modify my trans tunnel at all and the install went pretty smoothly. 

[Dino]

I like the A41 kit, and it has a better overdrive ratio than the GV. Not cheap though! My initial plan eas to shoe horn a T56 in there, but I really don't want to mess with the floor. I figured an auto with overdrive would be a cheap and easy option for now, but maybe I should just find a manual trans for that kind of money. It would need to have the shifter in the console though, not the hump.

[Mopar Nut]

I like the A41 kit, and it has a better overdrive ratio than the GV. Not cheap though! My initial plan eas to shoe horn a T56 in there, but I really don't want to mess with the floor. I figured an auto with overdrive would be a cheap and easy option for now, but maybe I should just find a manual trans for that kind of money. It would need to have the shifter in the console though, not the hump.

Go with a manual Tremec TKX 5 speed. You'll only need to cut a hole for the shifter. It fits where an automatic or manual console would sit. As long as you use the manual console plate.

[moparguy01]

A friend of mine had a tkx 5 speed in his coronet. He had problems with it. It turns out, he was overpowering it. It couldnt handle 650hp. He went to a 6 speed of some type and it works fine.

Also, if you go with a 700r4 or 4l60e, i was able to buy a modified drum for them from Cope racing transmissions. It has a cap on the end of the drum to help stop a common cause of those exploding. I put one before my almost 500hp 383 stroker in a c4 vette.

[Mike DC]

 

A friend of mine had a tkx 5 speed in his coronet. He had problems with it. It turns out, he was overpowering it. It couldnt handle 650hp. He went to a 6 speed of some type and it works fine.

Was he running big/sticky rear tires?  It puts more load on a tranny (and the rest of the drivetrain). 

That, and shifting hard at high revs.   
 

For really high power the 6spds are the way to go.  The ones that Tremec is making these days (both OEM cars & aftermarket) began as the Dodge Viper tranny in the 1990s.  They designed it from day one for big power + big tires + big abuse. 

Downside: The 6spds are physically much bigger (and heavier) than their TK0 & TKX 5spds.  In terms of cutting the car to make a stronger part fit, the 6spds are the nuclear option.  It means building a whole new tunnel (and the center of the T-bar crossmember) on a classic Mopar.  You're cutting a 2-foot-long hole in the floor big enough to climb your body through. 

[Dino]

Yeah I've seen what it takes to make the T56 fit and I'm just not willing to do it to my car. I cruise it and take it on long trips, but I never race it. Heck I rarely stomp on it. I'll look into the 5 speed. That sounds like a good option.

[Kern Dog]

Heck I rarely stomp on it.

   

[metallicareload99]

Is there an auto with overdrive that fits in a 69 Charger with 440, that does not require tunnels mods? I expect to fabricate or customize a trans crossmember and find a driveshaft, but I really don't want to mess with the floor. I prefer electronic control so I can use a US Shift Quick 4 and not have to worry about kickdown linkage. I don't care if it's a mopar trans or not, as long as it can handle the torque.

I don't know what your plans are for the car? Are you going to be racing it? What size tires? I figure if you're just wanting to cruise or are making big power than you don't "need" overdrive?

When I had 2.94 gears my 440 4-Speed cruised very well. I have 3.54 now and they are too tall for good acceleration and too low for "proper" cruising. 66 around @ 3,000 RPM is tolerable on the highway, but that really wouldn't cut it in america. I'd like to use at least a 4.30 gear at the track but that would require overdrive as they are of course far worse than 3.54's on the highway.

A friend of mine had a tkx 5 speed in his coronet. He had problems with it. It turns out, he was overpowering it. It couldnt handle 650hp. He went to a 6 speed of some type and it works fine.

Was he running big/sticky rear tires?  It puts more load on a tranny (and the rest of the drivetrain). 

That, and shifting hard at high revs.   
 

For really high power the 6spds are the way to go.  The ones that Tremec is making these days (both OEM cars & aftermarket) began as the Dodge Viper tranny in the 1990s.  They designed it from day one for big power + big tires + big abuse. 

Downside: The 6spds are physically much bigger (and heavier) than their TK0 & TKX 5spds.  In terms of cutting the car to make a stronger part fit, the 6spds are the nuclear option.  It means building a whole new tunnel (and the center of the T-bar crossmember) on a classic Mopar.  You're cutting a 2-foot-long hole in the floor big enough to climb your body through. 

Manual 6-Speeds? How does adding an additional gear make a transmission stronger? I totally agree the end use makes all the difference

Heck I rarely stomp on it.

 

I get where you are coming from, but a wiggle of my toe and I'm already racking up speeding tickets/@ risk of losing my license and I have maybe a legit 450 HP 

[Dino]

I like to open it up on the back roads, and cruise at 80 on the freeway, but the vast majority of my driving is in town, and I'm not gonna act stupid there. 
No track time at all. I just like to pull onto the freeway quickly and maybe stop to stop when it's quiet. I currently have 3.23 gears and they're alright, but an overdrive would be nice. I'm doing the same to my Gran Torino. Going from 2.75 with the stock 3 speed auto to 3.70 or thereabouts with an overdrive. 28" tall tires on both cars.

[Mike DC]

Manual 6-Speeds? How does adding an additional gear make a transmission stronger? I totally agree the end use makes all the difference

Of course it's not the additional gear, it's the transmission itself.  These days almost everybody uses versions of Tremec's big burly 6spd (either a junkyard OEM one or an aftermarket "T56 Magnum").

 

[Mopar Nut]

Manual 6-Speeds? How does adding an additional gear make a transmission stronger? I totally agree the end use makes all the difference

Of course it's not the additional gear, it's the transmission itself.  These days almost everybody uses versions of Tremec's big burly 6spd (either a junkyard OEM one or an aftermarket "T56 Magnum").

 

If he's going to cut it up to fit a 6 speed manual, Dino might as well put in the 8 speed automatic. A much better transmission.

[Kern Dog]

Not if you'd prefer to shift for yourself.
As good as many think the A8 is, it can also be a bit sluggish. Try slowing down from 50 to 10, then press the gas pedal half way down. It responds like a millennial cashier when you give them $ 20.15 for a $15.15 dollar purchase.....
Uhh....uhhh... OH, okay!

The one in our 2015 Challenger is fine during regular, normal driving but when you surprise it, it is slow to react.

[Mopar Nut]

Not if you'd prefer to shift for yourself.
As good as many think the A8 is, it can also be a bit sluggish. Try slowing down from 50 to 10, then press the gas pedal half way down. It responds like a millennial cashier when you give them $ 20.15 for a $15.15 dollar purchase.....
Uhh....uhhh... OH, okay!

The one in our 2015 Challenger is fine during regular, normal driving but when you surprise it, it is slow to react.

I actually prefer a manual, the A8 is much better if you paddle shift it. Does Mary's Challenger have paddle shift?

[Kern Dog]

It does.
Under throttle, it is hard to beat that A8. I haven't used the paddle shifters to downshift though.

[Mopar Nut]

It does.
Under throttle, it is hard to beat that A8. I haven't used the paddle shifters to downshift though.

You should link your excellent write up of the TKO install here, it'll give Dino an idea what to look for.

[Kern Dog]

It is here, it is just buried.

[Mike DC]

 
Purely a two-cents opinion: 

 
The 8-speed transmissions probably help the track numbers a bit.  But the (few) times I've driven one I didn't really find it more fun to drive.     

IMO increasing the number of gears past about 5-6 gets into diminishing returns.  Those gears aren't coming for free. It takes a lot of cutting the car.  And it adds mass, both rotating weight and raw weight.  An 8spd auto weighs 200+ pounds. 

The OEMs keep piling on gears but they have their own priorities.  They have to worry about tenths of a second in published performance tests.  And they go to extreme lengths over tiny gas mileage gains.  (Would you build an electric grille-shuttering system to reduce a tiny amount of aero drag at higher speeds?  Would you do that even on a dedicated track car, never mind a street pickup?) The fact that the OEMs want 8+ gears doesn't necessarily mean we should. 

[Kern Dog]

I heard Ford had a 10 speed automatic.

Pffft....Not impressed. I don't see the need.
When driving even my semi-modern 2007 Dodge truck with the 4 speed automatic, I wonder why the automakers stuck with 3 speed transmissions for so damn long. That 1 to 1 final gear really limits the versatility of the vehicle compared to something with a .7 overdrive. That simple overdrive allows a deeper axle gear for better all around performance while still allowing tolerable cruise rpms.

My Tremec 5 speed has the .64 fifth gear. that makes the rpms in overdrive about 2/3 of what you see in any torqueflite or regular 833 4 speed. Yeah....I would spin 2600 rpms at 70 before and 1850 after the 5 speed swap. The reduction in rpms carries many great benefits, not just the fuel savings. less engine wear, alternator, power steering pump, water pump and fan, oil pump....The engine will last longer.

[Mike DC]

 

When driving even my semi-modern 2007 Dodge truck with the 4 speed automatic, I wonder why the automakers stuck with 3 speed transmissions for so damn long. That 1 to 1 final gear really limits the versatility of the vehicle compared to something with a .7 overdrive. That simple overdrive allows a deeper axle gear for better all around performance while still allowing tolerable cruise rpms.

Top gear -

50-60 years ago the cruising speed on the highway wasn't as high on average.  There were 80 mph rural places but it wasn't common in the urban areas like now.   

Throw in the fact that the original owner usually ditched the car by 50-70,000 miles, and resale wasn't even a thing . . . they just didn't care about engine wear.  They didn't even give the engines moly piston rings.  And they certainly didn't care about gas mileage. 


Deeper axle gears & lower 1st gears -
 
Muscle cars were medium-heavy bodies + 400+ pounds of torque + 14x5 rims and bias-ply tires.  Low 1st gear ratios would have been pointless.  Not enough traction to use it. 

The 1st gear ratios were getting lower in the 1980s-90s when sporty OEM cars were up to 7-8" wide rims and radial tires.