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How many miles can you expect out of a 4.9 engine and transmission?

13358 Views 9 Replies 10 Participants Last post by  nycgavin
...without any major repairs.

I just bought a 92 eldo with 114000 miles and I'd like to keep it as a daily driver for as long as possible.

I know every car is different but I'd like to see what the average lifespan is.

How are the transmissions? I usually shift at about 2500-3000rpm.
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The engine, properly taken care of, will see well over 200,xxx miles without major repairs. The trannies however may become an issue around the 135,xxx mile mark.
'93 Eldorado w/ 4.9L. Original Engine and Trans. 190k and going strong.
This car has only two real weak spots: The cooling system and the trans.

The cooling system you can (and should) protect with annual coolant changes using the GM sealer tabs. With fussy maintenance a 4.9 is good for 300k+

The trans is another matter. The viscous converter clutch has a lifespan of about 150-180k (although some pass this limit and go on seemingly forever). There's really nothing you can do to preserve it, as frequently changing fluid often creates more problems than it prevents. Check your ODB codes often and watch for E39, that's usually the first sign.
I bought my '91 DeVille two years ago with just under 200,000 miles. Started getting the E39 code a little over a year ago, so I bit the bullet and had the transmission rebuilt at 214,000. I have no service history on the car prior to my ownership, so I don't know if anything has been done to the engine, but it's at 234,000 and runs perfectly. I drove it 4,000 miles round trip from Oregon to Iowa for the Cadillac Owners meet in May and had no problems, plus I averaged 23 MPG, even with the A/C on most of the time, the cruise set at 75 and crossing the Rockies.

I change the oil when the Oil Life Monitor drops below 20%, usually between 3,500 and 4,000 miles with Valvoline Max Life high-mileage oil. I've replaced some ignition components and had a tune up done right after I bought it, but that's it as far as the engine is concerned. There's a member here with a '93 DeVille that's close to 300K, and that's my goal for this car. I like it, and it's paid for.
Well, as far as the transmission goes, I've decided to do some preventive maintenance on my 95 sdv, I have only a little over 91k on it and put in an extra heavy duty trans cooler, ac/delco filter, and changed the fluid to conklin para-synthetic atf. So, maybe it'll last longer. I've read that the cooler you can make them, the longer they will last.
The 4.9 engine will soldier on forever. 200k+ is not an issue. I've never really heard of a trans going bad before 120k. Some go bad around 135k or so, while others last until near 300k (see above post).

The best advice I can give you re: the trans is to try and avoid full throttle upshifts. These are very hard on the trans. Feel free to floor it, but just lift off a bit before it shifts and it should help extend the life.

I don't really "baby" my cars, but I rarely floor them through multiple upshifts. I've never had a GM trans go bad on me and I've had cars with up to 175k miles on them without an issue. This includes the not-so-good THM200c trans, and it lasted for me for thousands of miles and I never touched it.

By the way, the 4T60E in your car is based off of the 4T60 or 440T4, introduced in 1985 (basically a 4T60E without an electronic shift solenoid and with a modulator valve and TV cable).

The 440T4 is pretty much a 4th gear added onto a THM125 trans that was introduced in the X-body cars (Citation, Phoenix, Omega, Skylark) in 1980. Being that the THM125 was originally designed to sit behind the "Iron Duke" 2.5L engine and the Chevrolet 2.8L V6, you can see why GM had problems with the first 440T4s--they had to handle much more torque than what they were originally designed for.

However, while these transmissions aren't excellent by GM standards, they're much better than anything from Ford or Chrysler.

A little bit of trivia: GM has supplied transmissions to BMW, Rolls Royce, Jaguar, Mercedes, Ferrari and many other companies. There's a reason why these top firms all chose GM as their transmission supplier.
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A little bit of trivia: GM has supplied transmissions to BMW, Rolls Royce, Jaguar, Mercedes, Ferrari and many other companies. There's a reason why these top firms all chose GM as their transmission supplier.
Subaru use some GM Trannies too. GM makes an excellent transmission.
Infact, like you were saying, The 4l50E in the CTS was first used by BMW.
240km on 92 eldo etc, just a couple ignition problems still going very strong knock on wood
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