General Motors 4T60-E Auto Overdrive Tranny

jharley1

Does anyone have any experiences they would like to share regarding the 4T60-E Automatic Transaxle that GM used in the Cutlass/Malibu and Achieva/GrandAm line of cars in the mid to late 90's? I've heard they have a tendency to be a little weak and wondered what others were doing to avoid transmission failure.

jrosasmc

Don't tell me this is the same transmission that was also installed in every FWD Cadillac and RWD B-bodies back in the mid-90s.

alcan

It isn't.

4 = forward speeds
T = transverse mount transaxle (incorporates the final drive and differential in the same housing, FWD in all except the old Pontiac P body)
L = longitudinal mount RWD transmission
60, 65, 80 = relative torque capacity range
E = electronic control of shift points, line pressure modulation, and torque converter clutch

4T60-E transaxles were used in most FWD applications with engines up to and including 3.8L supercharged until they were replaced by the 4T65-E in 97/98. Cadillac and Olds Aurora use the higher capacity 4T80-E transaxle. Most RWD applications use the 4L60-E transmission. Heavy duty RWD use the 4L80-E.

No common sub-assemblies are used in the different series of transaxles or transmissions.

campo57

Well, I had one in my '92 Bonneville SSE with the 3.8L and never had a problem with it. In fact, you could say I abused it but not changing the fluid and filter until aroun 100K miles. When I changed them, the fluid looked good, wasn't that dirty and the filter didn't look bad.

I sold the car with 121K on it and it's still running fine.

Campo57

ata3001

I installed an external transmission oil cooler on the front of the radiator of my 99 Grand Am GT right in line with the lower opening of the front facia. I've been told by my local & trustworthy transmission mechanic that lowering the transmission oil temperature 20 degrees can double the life of the average transmission. I also service the transmission yearly. Compared with the cost of a transmission replacement, this is cheap. ;-)

alcan

ATF at 180F has an expected lifespan of 100,000 miles before it starts oxidizing to the point where it start breaking down and forming varnish. At 400F that lifespan is 25 miles.

q45man

and siting in Summer traffic can cause the Fluid as it passes through the torque convertor to spike over 260F maybe 300F but the radiator heat exchanger tries to cool it [to what ever the coolant temp is 180-200F]...... 180F pan temperature is not a very good indicator of PEAK temperatures.
In winter the radiator heat exchanger helps heat up the fluid, when the temp comes up but this takes at least 10 minutes from cold start.....an excellant reason to use premium sythetic ATF to avoild wear when cold started [much like engine].
A very good reason to change ATF at least every 2 years in late spring before the summer season frys it.

mark4444

My '95 Monte Carlo with the 3.1 motor & 4T60E had 75,000 miles on it when the transmission fluid started to turn dark. The problem was caused by the pin breaking that holds the differential cross shaft in place. The cross shaft was rubbing against tha inside of the differential case - it finally wore a hole in it. I am picking the car up tomorrow - $1500 repair bill. Another example of "that great GM feeling".

jsl55

That's not bad. My '90 Grand Prix trans cost $1500 back in 1997. (Must be the low inflation or all the experience rebuilding them makes an economy of scale.) I then sold it and bought an Accord. BTW, how many alternators, front brake pads and rotors does a Monte Carlo eat? The GP loved them. Not to mention the speedometer head going bad at 120,000 and the paint peeling off (white).

oldsman01

I believe the Cutlass and Malibu use the 4T40E or 45E as the 4T60E was used in larger cars. The 4T60E is a good trasmission and has actually been upgraded to the 4T65E which is used now.

mark4444

The real culprit on my '95 Monte Carlo was one of the pinion gears in the differential seizing onto the differential cross pin, causing it to turn in the case. The rotation of the cross pin not only broke the hollow split pin that holds the cross pin in position, but also caused the cross pin to break near the other end, part-way through the opposite pinion gear. This small end of the cross pin then started coming out of the differential case, scraping on the inside of the aluminum housing. The aluminum particles from this scraping action was causing the fluid to turn dark. The extension housing finally got too thin and cracked from the cross pin end rubbing on it. This happened as I was backing the car out of the driveway to be loaded onto a flat bed truck to be taken to the transmission repair shop. I'm glad I decided to have the vehicle towed as the repair bill would surely have been much higher if the extension housing broke while travelling down the highway.

alcan

During straight ahead driving the pinions do not rotate on the shaft, IF the tires are the same circumference. The pinions (and axle shafts) rotate only when the wheels are turning at different speeds, providing differential action. Pinion shaft failure due to a pinion seizing to it is usually associated with high pinion rpm. Most common cause is spinning one tire (on ice, etc), followed by sustained high speed driving with unequal size tires. Having a spacesaver spare tire on one side of a drive axle can cause the problem. If neither of the above apply, have the trans shop check the circumference of both front tires by measuring around them with a string.

mark4444

I have not measured the front tires' circumference yet, but they are both marked with the same size. The spare has never been out of the trunk. Spinning on ice sounds like the most likely culprit, but I noticed the fluid turning dark late last summer. If it was ice, it had to have happened last winter.

My first impression was that transmission fluid may not provide adequate lubrication like regular gear lube does. But, if that were the case, lots of transaxles would have their diff pins failing. The extreme pressure qualities of gear lube are required for hypoid gears I guess, and since the differential in the 4T60-E is driven by a planetary gear arrangement, transmission fluid should be adequate.

Thanks

alcan

Mark, you probably nailed the cause with the spinning on ice. As to the tire circumference issue, it's not uncommon for 2 tires from the same manufacturer to be different. Not usually a problem on 2 wheel drive, but it's been the cause of some grief in full time all wheel drive systems, causing the transfer case or torque divider to bind up.

yurakm

You are right, 4T40-E is used with Malibu / Cutlass

http://www.gm.com/automotive/gmpowertrain/transmissions/4t40_main.htm

with 4T65-E used with 3.8l engines on several cars and minivans:

http://www.gm.com/automotive/gmpowertrain/transmissions/4t65_main.htm

The 4T60-E is not available any more:

http://www.gm.com/automotive/gmpowertrain/transmissions/index.htm