Transmission Oil Flushing

[Spindrift]

I'm planning to change the dino oil in my 4L80E tranny to a synthetic so I thought I'd make a couple of calls to find out how much a shop would charge for a tranny oil flush.

One guy recommended against the use of a transmission oil flusher on higher mileage vehicles that haven't had regular tranny oil changes. He said the flushing process could loosen up a transmission by removing the glazing on internal parts. This will ultimately lead to transmission failure. He'll do the flush but he wants me to hold him harmless against any future problems I might experience.

My truck has 85K on the odometer. I bought it used with 80K. I wasn't able to verify if the previous owner had changed the fluid.

I am going to change over to synthetic. The question is, given the circumstances, is flushing the way to go?

Thanks.

[LanduytG]

Kind of a good indicator is what does the oil look like now? If it is a nice red color or maybe even if its a little brownish then I would go ahead and flush it if it were me. I changed mine at 80K and it had never been done before and its still running strong at 163K. It is really a tuff call to make, you just need to go by your gutfeeling.


Greg

[taznj63]

When I bought my truck last year it had 126,000 on the clock and the tranny was not working right. :eek: I had it flushed, new filter, and had a set of solenoids installed and the trans is a good as new!!! :D I now am at 146,000 and still working great. The solenoids clog up with gunk and start sticking so $120 in solenoids beats $2000 for a transmision. So I feel that a flush at 85K is not going to be a problem. Just check the fluids and change the Sol's when the filter is changed. There are 4 total, 2 for 1-2 and 3-4 shifts, 1 for TCC, and 1 for line pressure.
Hope this helps... :cool: