Rebuilt 4L60 Service Advice

tyhuck · March 16, 2013

I had my transmission rebuilt last August, and the guy that built it told me to change the fluid every year, or 15k, whichever came first. Ordinarily, i would be ok with that, but the whole reason I had to have the rebuild was because I changed the fluid and it caused me to loose my 3rd and 4th clutches.

I know that if the fluid isnt burnt, its ok just to leave it alone. I had a 96, and an 06 pickup, both with 4l80Es, that went forever without a change. the 96 is pushing 200k with the guy that bought it from me with the same fluid.

So, I need advice. The transmission has been upgraded with all new clutches, new valves, new seperator plate, and a complete Trans-Go shift upgrade kit. im also running a Black Bear tune and 35" tires onfactory 3.42 gears. most of my driving is highway driving, but during deer season i do tow my electric golf cart on my 5x10 utility trailer 3-4 times per weekend (40-50 miles each trip). All of those factors concidered, What would you do?

txab · March 16, 2013

I'd probably do 40k. Wouldn't once per year, 15k that's just overkill, based on your use. Run a quality synthetic.

Have you already added additional cooling for the trans?

tyhuck · March 17, 2013

All I have on it is the factory trans cooler. According to my Autometer gauge, the temp rarely goes above 190-200, even in the summer (100 deg +). In the winter, it barely gets over 115. it usually runs around 180 on a warm fall day, even with the 35s on and towing my golf cart.

I forgot to mention, I do pull about 6k worth of tractor and equipment for about 8 miles over some really hilly terrain, but only once or twice a year, so it really shouldnt metter much.

As far as the changes go, Im just wasnt sure if having the shift kit would require more frequent changes.

txab · March 17, 2013

Not to my knowledge. You might go 30k if you have concerns. With today's synthetics, the fluid holds up very well.

KMGZ400 · March 17, 2013

I had the same thing happen to me on my 03 burb when i changed the fluid. I was always under the impression that your change the fluid every 30k, or dont change it at all. i have 140k on my original trans on my 03 with no issues. dosent smell burnt

gmtech4 · March 28, 2013

changing the oil does not kill the 3-4 clutch ,,,,they blow up all by themselves nicely !!!!

tyhuck · March 28, 2013

The tech told me that the clutches were probably nothing but glazing and buildup anyway, and the fresh fluid cleaned them up. No more buildup, no more friction. He showed me the clutches, and they were pretty clean (bare metal) especially compared to the others.

Not sure if that was the case since I dont know much about transmission internals, but thats what he told me.

music · March 28, 2013

GM's recommendation is every 50k miles under hard use, or every 100k otherwise. I'm going w/ the 50k mile interval, since I tow. Never had a lick of problem out of my '99 w/ a 50k change.