Rodgermac

My mistake cost me the 4R70W transmission in my 2001 F150. We're replacing it with a new one. I've read stories about changing the fluid then the transmission goes bad, but chiltons recommends changing every 30,000 or two years. The truck has 137,000 on the old one. So I figure I should maybe take better care of the new one. What's the wisdom here? Change it every 30,000/2yrs. or a combo of things. Thanks Rodger

whomrig

Hi Rodger, yes keep up the maintenance maybe even change trans fluid at 25k
I follow the factory maint. schedule (30k) and it does pay off.
What did happen to your transmission? As for the stories of changing trans fluid then see it go south, I don't know either way.

Rodgermac

Long story. Hit a deer, cracked cooler line, drove two miles home, transmission didn't fair good. Replaced cooler, changed oil & filter. Transmission went another 500 miles before slipping.

whomrig

Sounds like a replacement trans is in order.

Jacob.P93

The only reason the trans is gonna go out after a fluid change is the went way way past on the fluid change so the trans gets used to running with a bunch of crap packed in everything. So you go and flush all the crap out and your trans is to sloppy to maintain normal function. Or they were experiencing slip and flush it out and it fails shortly after. For you and your trans just be mindful of o/d going in and out over and over again. I run 50k on my trans flushes with a filter and adding the fluid that was lost at 25k.

me1234

I had a 4R70W in my 2000 2wd that went out at 60k(wtf right??). It was slipping and I got a flush to see if it'd fix the problem. It didn't, and the trans died 3 days later barely getting me home. Since it was already slipping, I know the flush didn't cause the issue, I'm pretty sure it just made it worse.

Anyways, I have a fear of trans flushes now, so the new trans won't be getting one. I'm just going to get fluid changed/change it myself every 15k and change the filter every 30k. I figure that's more maintenance than they usually get so I'm not loosing too much opting out of the flushes.

The reason I opted for 15k fluid changes is I remember reading somewhere(owners manual?) that the fluid should be changed 15k for "heavy duty" usage and 30k for standard. "Heavy duty" is a lot of towing or constant stop and go traffic, standard use is almost all highway miles. I honestly don't remember where I read that, but after the last trans dying so early I'm going the better safe than sorry route.