Transmission failure

[Jammer]

The transmission in my truck failed yesterday. It will have to be replaced.

My 1997 Chevrolet truck has the 4L80e transmission, which has a good reputation. Since this is a plow truck in the winter, and TV in the summer, the transmission has a hard life.

I'm curious whether anyone has experience with any of the common transmission upgrades -- oversize pan, improved clutches with more apply area, higher-stall torque converters.

Also a question as to whether a transmission temperature gauge would have given advance warning of the impending failure to save the cost and inconvenience of an unexpected failure on the road.

[jcanavera]

Two things you should consider. One being a transmission cooler. Snow plowing can heat up trannys pretty quick. My neighbor is a landscaper who also plows snow in the winter. He has replaced transmissions on his pickups. I'm sure the temperature gauge would have helped but in all honesty the cooler will be a big plus.

The other item is you probably should do an annual transmission oil change. That heat build up will shorten the life of the oil and an annual change of the oil and cleaning of the filter will go a long way in giving you added service life.

Jack

[HowieE]

Things I did to my 97 4L80 were the installation of a fan driven cooler in line with output line, adding a cooler forward of the radiator, and removing the trans lines from the radiator all together. This controlled the trans temperature to 165 degrees in the summer and as low as 100 degrees in the dead of winter.

I installed a BD Torq Loc for manual control of the converter. This would not have any effect on plowing since it only allows the locking of the converter above 33 mph but for towing it is the greatest thing since sliced bread. The draw back with the Torq Loc in the 97 trans is if used in an automatic mode it will set a 0742 code and set the trans in limp mode. However if used manually you can not beat it. I have pulled hills with a cool trans that I would have never made it to the top without boiling the trans. I can lock the converter in 2ne 3rd of 4th gear.

The trans now has 197,000 miles of which 100,000 is towing at 16,540 lbs.

While I did not post comment on the trans in my truck you may find other info on my site. HowieE

[Jammer]

Thanks. I do have an aux transmission cooler, and perform frequent fluid and filter changes.

I had checked the fluid a week before the failure and there were no signs of overheating. Due to the catastrophic nature of the failure, I believe that a clutch, bearing, or some other internal component came apart and threw enough debris everywhere to wreak havoc.

[r carl]

Best thing that you can do that i know of is to use this stuff. Cost ya about 200 for a case delivered to your door.
http://www.le-inc.com/products/documents/1150_flyer.pdf

[TomW]

Originally Posted by Jammer

...Also a question as to whether a transmission temperature gauge would have given advance warning of the impending failure to save the cost and inconvenience of an unexpected failure on the road.

My observation is that people who will monitor (or even want) a transmission temperature gauge are not inherently the type of people who will abuse a transmission in the first place. These people know to take it easy on steep grades or gunning the engine in reverse to park an Airstream on an uphill slope.

If you do decide to get a gauge, the kicker is where the sensor is located. The sensor in an aftermarket kit will most likely not be at the ATF's hottest point. A factory gauge & OEM sensor location would be best.

I was thrilled with my '99 Silverado's factory tranny temp gauge until I read that it ultimately does not matter - it will never read too hot because the onboard computer will throttle the motor back if it feels the tranny is too hot.

Tom

[jcanavera]

Originally Posted by Jammer

Thanks. I do have an aux transmission cooler, and perform frequent fluid and filter changes.

I had checked the fluid a week before the failure and there were no signs of overheating. Due to the catastrophic nature of the failure, I believe that a clutch, bearing, or some other internal component came apart and threw enough debris everywhere to wreak havoc.

It is entirely possible that the fact that you plow snow might be the contributing factor. Sounds like overheating wasn't a cause since you noted that you checked the oil the week before. Overheating does cause a color change in the fluid. I assume that was how you determined that there were no signs of overheating.

If you plow smaller business lots, you do a lot of reverse to forward shifting. The tranny, dependent upon speeds is doing a lot of down and upshifting also. I always wondered whether the impact of snow drifts, blocks of ice could have a contributing effect that might shorten the life of an internal component.

For all intents you seem to have done what is necessary from a maintenance standpoint.

Jack

[Silvertwinkie]

Since doing this, my trans barely gets to 180 degrees in warm weather, towing and does not get too cool in the winter. Before doing this I would get near 200 degrees.

http://www.airforums.com/forums/f463...des-51433.html

[overlander63]

Originally Posted by Jammer

Thanks. I do have an aux transmission cooler, and perform frequent fluid and filter changes.

I had checked the fluid a week before the failure and there were no signs of overheating. Due to the catastrophic nature of the failure, I believe that a clutch, bearing, or some other internal component came apart and threw enough debris everywhere to wreak havoc.

Probably the gear train blew apart. It's not that common, but from the sudden load of hitting a drift, it can cause micro stress cracks that can fail when subjected to heat or load.

[garry]

In my case a gage would have helped 1996 GMC 135,000 miles no problems flushed twice.

I was pulling the AS maintaining 65 mph when I stopped for gas I realized the head wind was much stronger than I thought 45 gusting to 60 when I started to pull out of the gas station the transmission was slipping pretty bad. I let it cool down for 30 min and took off very gently with just a little slip 150 miles to home. Driving 45 to 50 the transmission gave up 8 miles from home. Had a friend come get the AS and I was able to drive home.

I replaced with a GM transmission for the 50,000 mile warranty good at any GM dealer figured I would replace the truck before then so no options or upgrades.

I feel a gage would have warned me something was going on or if the wind was from the side I would have known to slow down.

[Jammer]

Thanks for the posts. Silvertwinkie, I did read through the linked thread and found it intriguing.

I bought this truck from a guy who was in a variety of enterprises, snow plowing among them. He had his employees driving the truck. Who knows what they did to it. I've had it for two winters and have been clearing the snow from my own driveway and that of neighbors. It does entail a great deal of shifting, forward to reverse. So it's seen more shifts than most. I knew the history when I bought it but it came with the plow and the price was right ::shrug:: so no regrets, really.

[HowieE]

Garry

Towing into a headwind of that strength you were most likely towing in 3rd with the converter unlocked. A recipe for an overheated trans.

There are 2 modes that are musts for towing. A trans cooler and a temperature gauge

You can not over do cooling. My trans runs at 100 degrees in the winter and 165 in the summer while towing.

[TomW]

Originally Posted by HowieE

You can not over do cooling.

Actually, you can.

Most tranny cooling systems are designed to allow the engine's radiator to heat the tranny to optimum temperature immediately after the engine is started. Call it "pre-warming".

If aftermarket cooling items are added, make sure the plumbing allows the transmission to heat up (like the engine) before a load is imposed.

Check with professionals before adding additional cooling capacity to make sure the cooler is on the correct ATF flow path.

Tom