96 4L60E Too Flush or Not

[Erik the Awful]

I think most of the guys who bag on the 4L60s are running big tires or drag racing. For normal truck work it's sufficient. My Suburban had 220k with no transmission issues. My current truck looked like a mobile meth lab when I bought it, and the transmission was broke, but it was apparent it had been abused and submerged.

 

[Schurkey]

So how were these trucks so great with how much everyone caps on the small block tranny?

The 700/4L60/4L60E family of transmissions was a mess when introduced, and was NEVER strong and durable like the older 350 or 400 trans. The design work was done in an era of V-8 engines that had pathetically little power.

OTOH, they got significantly better fuel economy than the non-overdrive transmissions.

After about three hundred GM updates, they're now "adequate" for stock engines in most situations. And of course the aftermarket has a huge array of expensive "hot-rod" parts for them.

So, yes, the 700-series transmission is a let-down. Doesn't mean the rest of the vehicle can't be salvaged. They'll work just fine...for awhile. My Trailblazer trans has a quarter-million miles on it; and still works fine.

I'm not too fond of the 8.5" rear axle in a full-size truck, either.

 

[alpinecrick]

So how were these trucks so great with how much everyone caps on the small block tranny?

Having owned every generation of GM truck--often multiple examples--- from the AD series to the K2XX, with the exception of the GMT900........

The old original 2 speed Power Glides--with scheduled maintenance--were good for 75k miles or so before they gave out. And yes, racers are running 2000 hp with Power Glides but they are built from the ground up to race, and the Power Glides have LOTS of room inside them to install bodaciously big, heavy duty parts to hold up.

The Turbo-Hydramatic 350--with scheduled maintenance--was good for 100k before they broke (having broke a few, I know this). The TH350 is a similar design to the Power Glide.

The 4L60E (we'll just skip through the 700R and 4L60) is a TH350 with overdrive installed in the tail--and with scheduled maintenance--generally last 150k miles (all four 4L60E I've owned that broke, did it between 155k-160k miles). The electronic versions probably last longer than the non-electronic 4 speed trans precisely because of torque management ability.

In other words the GM "light duty" auto trans have improved their lifespan over the years. It's important to note any hydraulically driven automatic transmissions are inherently hard on themselves, and it doesn't matter what brand or design we consider.

It would have been nice to have all the GM half tons come with 4L80E's, but it is all about cost---and cost is why half tons are more popular than 3/4 or 1 tons. Nor is it fair to compare a less expensive trans to a more expensive trans. We can just blame the original buyers of these half tons of being cheapskates........

It's also important to note that todays Turbo Diesel "HD" trucks have much more extensive torque management program because even my vaunted Allison transmission (and drivetrain) can't handle all the torque at once my 06 Sierra TD makes. And today's TD's in the HD trucks are a LOT more powerful and can grenade any part of the drivetrain in a heartbeat without torque management.

Equally important, the introduction of the Vortec motors upped the ante quite a bit in the hp and torque game. The 5.7 L31 made 330 ft/lbs of torque, and in comparison the awesome original LT-1 small block made about 370 ft/lbs of torque. The LT-1 was a full blown hotrod motor in the muscle car era, the L31 is a everyday workhorse motor.

The GMT400's were not only an improvement, they were such an improvement over earlier generations of trucks the Chevy and GMC GM400 series of pickups and SUV's combined were easily the most popular trucks sold during the late 90's.

 

[FLJoe]

I'm late to this thread, but will give just a little input. I've owned my 96 4WD Tahoe since 99 when it had about 30,000 miles on it, so I've put the other 480,000 on it. It has a factory tow kit, which includes a small external cooler. Every 50,000 miles like clockwork I dropped the pan and changed the filter. I tow with the truck (a 28' heavy boat). When I'm towing, I drive like a 90 year old granny to go easy on the shifts, and when I pull up the ramp I use 4-low to ease the load on the drivetrain, especially the transmission. Otherwise, I drive the truck like a normal DD, and don't hammer the transmission or engine.

My original transmission lasted 440,000 miles with absolutely ZERO issues. I finally replaced it when it was getting a minor slip between 1/2, and it had developed a whine in first gear. I put in a GM reman unit with the 100,000 mile warranty, rather than have my ancient unit rebuilt.

So, from my limited experience, if you don't drive like Don Garlits, drop the pan every 50, and keep it cool, there's nothing wrong with the 4L60 and it can last a very long time.

 

[SUBURBAN5]

Having owned every generation of GM truck--often multiple examples--- from the AD series to the K2XX, with the exception of the GMT900........

The old original 2 speed Power Glides--with scheduled maintenance--were good for 75k miles or so before they gave out. And yes, racers are running 2000 hp with Power Glides but they are built from the ground up to race, and the Power Glides have LOTS of room inside them to install bodaciously big, heavy duty parts to hold up.

The Turbo-Hydramatic 350--with scheduled maintenance--was good for 100k before they broke (having broke a few, I know this). The TH350 is a similar design to the Power Glide.

The 4L60E (we'll just skip through the 700R and 4L60) is a TH350 with overdrive installed in the tail--and with scheduled maintenance--generally last 150k miles (all four 4L60E I've owned that broke, did it between 155k-160k miles). The electronic versions probably last longer than the non-electronic 4 speed trans precisely because of torque management ability.

In other words the GM "light duty" auto trans have improved their lifespan over the years. It's important to note any hydraulically driven automatic transmissions are inherently hard on themselves, and it doesn't matter what brand or design we consider.

It would have been nice to have all the GM half tons come with 4L80E's, but it is all about cost---and cost is why half tons are more popular than 3/4 or 1 tons. Nor is it fair to compare a less expensive trans to a more expensive trans. We can just blame the original buyers of these half tons of being cheapskates........

It's also important to note that todays Turbo Diesel "HD" trucks have much more extensive torque management program because even my vaunted Allison transmission (and drivetrain) can't handle all the torque at once my 06 Sierra TD makes. And today's TD's in the HD trucks are a LOT more powerful and can grenade any part of the drivetrain in a heartbeat without torque management.

Equally important, the introduction of the Vortec motors upped the ante quite a bit in the hp and torque game. The 5.7 L31 made 330 ft/lbs of torque, and in comparison the awesome original LT-1 small block made about 370 ft/lbs of torque. The LT-1 was a full blown hotrod motor in the muscle car era, the L31 is a everyday workhorse motor.

The GMT400's were not only an improvement, they were such an improvement over earlier generations of trucks the Chevy and GMC GM400 series of pickups and SUV's combined were easily the most popular trucks sold during the late 90's.

X2

I'm late to this thread, but will give just a little input. I've owned my 96 4WD Tahoe since 99 when it had about 30,000 miles on it, so I've put the other 480,000 on it. It has a factory tow kit, which includes a small external cooler. Every 50,000 miles like clockwork I dropped the pan and changed the filter. I tow with the truck (a 28' heavy boat). When I'm towing, I drive like a 90 year old granny to go easy on the shifts, and when I pull up the ramp I use 4-low to ease the load on the drivetrain, especially the transmission. Otherwise, I drive the truck like a normal DD, and don't hammer the transmission or engine.

My original transmission lasted 440,000 miles with absolutely ZERO issues. I finally replaced it when it was getting a minor slip between 1/2, and it had developed a whine in first gear. I put in a GM reman unit with the 100,000 mile warranty, rather than have my ancient unit rebuilt.

So, from my limited experience, if you don't drive like Don Garlits, drop the pan every 50, and keep it cool, there's nothing wrong with the 4L60 and it can last a very long time.

Damn 480k that's impressive. I thought mine had a lot at 472k. I agree 100% on this statement. How you drive and maintain a trans is how long it could last. I can kill any transmission. Doesn't matter the brand or gears. I have a heavy foot and the burb is not a light body. So our original trans didnt last that long. Awesome job keeping it alive that long!!

 

[FLJoe]

Suburban5, thanks. The odometer now reads 484K, but the odo/speedo read 3% low because I've always had 265 tires on it, so it's really somewhere over the 500 mark now. Keeping it going that long is nothing more than treating it with some care, and immediately fixing even the most minor problem, so they never stack up, and it never starts feeling old. I also have the advantage of knowing an outstanding drivetrain mechanic, and he's gone through all the gearboxes over the years for new bearings/seals and gear setup. The engine is all original, and the heads have never been off (just intake manifold gaskets). Just change the oil every 3-4000 and never overheat it.

 

[SUBURBAN5]

Suburban5, thanks. The odometer now reads 484K, but the odo/speedo read 3% low because I've always had 265 tires on it, so it's really somewhere over the 500 mark now. Keeping it going that long is nothing more than treating it with some care, and immediately fixing even the most minor problem, so they never stack up, and it never starts feeling old. I also have the advantage of knowing an outstanding drivetrain mechanic, and he's gone through all the gearboxes over the years for new bearings/seals and gear setup. The engine is all original, and the heads have never been off (just intake manifold gaskets). Just change the oil every 3-4000 and never overheat it.

Yes that's the key to owning a vehicle
In my case I'm trying to start with a clean slate and replacing everything that's worn out from the original miles and giving her a second life so I can pass it down to my son, if he ever wants it lol

 

[alpinecrick]

My original transmission lasted 440,000 miles with absolutely ZERO issues.

Holy Mother Of Pearl. You are my hero.........

 

[Caman96]

Suburban5, thanks. The odometer now reads 484K, but the odo/speedo read 3% low because I've always had 265 tires on it, so it's really somewhere over the 500 mark now. Keeping it going that long is nothing more than treating it with some care, and immediately fixing even the most minor problem, so they never stack up, and it never starts feeling old. I also have the advantage of knowing an outstanding drivetrain mechanic, and he's gone through all the gearboxes over the years for new bearings/seals and gear setup. The engine is all original, and the heads have never been off (just intake manifold gaskets). Just change the oil every 3-4000 and never overheat it.

Good to hear FLJOE! And that’s exactly how I plan on driving it. I bought it with 46k last summer so I can’t say when or if pan,filter or fluid was ever changed. I immediately dropped pan and changed filter. It looks clean still. I did just add OE cooler, PCM is at Black Bear Performance, when it’s back in I’m doing the complete fluid transfer method mentioned earlier in this thread, while also adding new aluminum pan and filter. Magnetic drain plug will allow fluid to be refreshed often. Also got my new GlowShift temp. guage with Stubby sensor. And when towing the 2 Atv’s will just take it easy! Thanks for all the input from all you guys. I got a question that is off topic though. Any special trick to pulling the headlight switch knob off?Doesn’t seem to want to pull straight out like other knobs.

 

[alpinecrick]

Suburban5, thanks. The odometer now reads 484K, but the odo/speedo read 3% low because I've always had 265 tires on it, so it's really somewhere over the 500 mark now. Keeping it going that long is nothing more than treating it with some care, and immediately fixing even the most minor problem, so they never stack up, and it never starts feeling old. I also have the advantage of knowing an outstanding drivetrain mechanic, and he's gone through all the gearboxes over the years for new bearings/seals and gear setup. The engine is all original, and the heads have never been off (just intake manifold gaskets). Just change the oil every 3-4000 and never overheat it.

I preach keeping fluids looking like new on here like a broken record....

I have drain plugs on all five of my 4L60E's and every third or fourth motor oil change I pull the plug and drain the ATF, then refill. I bought my 97' K1500 from the original owner who was the parts manager at the Chevy dealer in town. Before I ever bought the truck from him he preached keeping the ATF bright red. That 97 has a 166,*** miles on it with the original trans, and is a new personal best when it comes 4L60 longevity.