Are Your RPM’s Too High? Lower Them With A Re-Manufactured Overdrive Transmission.

Posted by on Wednesday, October 24th, 2012

Classic muscle cars built in the 1960’s and 1970’s were often built to do one thing real good; go quick in the quarter mile. Gas was cheap and gas mileage was not a big concern. It was not uncommon to find a muscle car with 4:10 or higher gears. While this was great for quarter mile performance it really hurt the car’s gas mileage.

Classic 1969 Camaro Z28 Muscle Car

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In the early 1960’s the 2-speed Powerglide was the standard automatic transmission. Then came the three speed TH 350 and heavy duty TH 400 transmissions.  The problem was that all three transmissions had a 1:1 final gear. Cars equipped with these transmissions and 4:10 or higher gears would typically turn over 3000 rpm at 60 mph. Not good for your gas mileage. In fact if left original, these cars often have a hard time keeping up with modern cars at modern highway speeds.

2-speed Powerglide Transmission

Source: Google

So how do you go about fixing this problem? Install one of General Motors overdrive transmissions.  Here are your choices:

200R4 – This transmission can be found in cars like the Buick Grand National.

700R4 – These transmissions were the first of the GM overdrives.

4L60 – A modern version of the 700R4. Good choice for mild small block equipped cars.

4L60E – A full electronic version of the 4L60. Requires a computer to operate.

4L80 – Heavy duty 4-speed found in many trucks and heavy duty applications. Great for high horse power vehicles.

4L80E – Full electronic version of the 4L80. Requires a computer to operate.

Cut-away of modern General Motors 4L80E overdrive transmission

Source: Google


You could take a gamble and try to find one on Craigslist, or you could save yourself a lot of grief and headaches by ordering a re-manufactured GM overdrive transmission from ETE .  Each transmission from ETE comes with a full 3 year / unlimited mileage warranty. That includes paid labor and an immediate replacement unit in the rare event that one fails.

You will also need a torque converter, TV cable (non-electric transmissions), new cooler lines, a stand-alone computer controller (electron transmissions) and possibly a new or modified transmission mount and a shifter (or upgrade your factory shifter).

Put the fun back into your muscle car with a GM re-manufactured overdrive transmission.

Sooner or later due to high mileage or abuse, you will be faced with a decision to replace your transmission. I highly recommend you replace it with a re-manufactured transmission over one that was simply rebuilt. A re-manufactured transmission will include major modifications and upgrades designed to make it both more durable and stronger. A rebuilt transmission will not. A re-manufactured transmission also comes with a much better warranty: three years compared to an average 90 days for a rebuilt unit. Let’s not forget to mention that after-sales customer service is top notch for companies that re-manufacture transmissions. They are a quick call or email away in the rare event you may need to contact them.

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