140k 2gen auto trans: drain and fill or ?

I'm getting a little shy with the wrench after buying 8qts of trans oil from the dealer. The trans has never had a drain and fill or flush since new and I know this because my brother in law has owned it since new and said if you didnt find a receipt for it in glove box, it didnt have it done. It's had a pretty easy life outside of gridlocked California traffic. Base 2wd single cab. No hitch to even tow and he didnt do much travel up and down mtns from what I know.

Reason for my delay:

1) the fluid is a little darker than I'd like to see
2) some of the auto trans horror stories of changing the fluid having adverse effects. I think the main thing are valves getting gunked up with more sediment going through them. New oil cleans the insides more and frees up more dirt. So that's my dilemma.

Do I
1. 4qt drain and fill?
Or
2. Pop the pan off, clean it out, change filter and refill. 30k later do a 4qt drain and fill.

3. The full monte: filter change, flush fluid by consecutive drain and fills

 

My trans with the a340e took 7 quarts, I had the pan down for 6 hours so i think a ton drained because of that. mine was a little darker than normal after 120k highway miles. 30k a year before i got it. I would think you would be fine with just the drain and fill, i noticed crisper shifts after the service. although be prepared to have a really hard time with that orange rtf.

 

Yeah, I'm not looking forward to the rtf job. Been a long while since I've done a gasket like that.

Did you have gunk in the bottom of your pan or notice a lot of buildup in the filter?

 

If i was in your position. I wouldnt do a full flush but rather 2 drain and fills. Follow the procedure for a drain and fill and then drive it a couple thousand miles and do it again. you have less of a chance of damaging the tranny that way.

 

There’s a write up on here about how to do a Fluid Exchange. Flush is the wrong word. With the fluid exchange the transmission pump runs like usual and draws up dirty fluid from the pan. After that fluid has circulated, instead of returning to the pan, it pumps into a reservoir. Clean fluid from another reservoir is returned to the pan.

There’s no chemicals or pressure to loosen debris or damage anything.

If you do it this way you end up with a tranny full of fresh fluid and not 4 litres of clean fluid contaminated by 8 litres of old burnt fluid.

 

I've seen the one for the v6 trans, not the 4cyl. Will have to search some more. I know it involves using the transmission cooler lines which this truck does have.

New fluid can act as a cleaning agent. Good fluid generally has detergent in it and certain other things that keep from sludging up.

 

Did you use a gasket when replacing the pan back or rtf?

 

You can do it by removing the pan, there will be a pump pick up nozzle and a return nozzle in there.

 

I did a gasket once and a rtf the second time when I found that the previous owner stripped the bold. Rtf is easier to put back on. There was no gunk on mine, just clean the pan and magnets and it was good.

 

Well, I think I'm just going to do some drain and fills for the meantime. Maybe in 30k I'll do a pan off and filter. I dont want to f with it much right now. The seal on the trans pan is perfect. Trans works well. I hear the filter in there is not a small particulate oil filter, its metal so it's mainly a debre filter so the main benefit you get from dropping the pan is cleaning the magnet off. I'll unhook the tranny cooling lines and get some extra fluid out on the first dump and keep track of how much I pulled out.

 

Yes the AT filter is not really a filter, it's more of a screen (fine particles will get through). Since you are hesitant to drop the pan, a simple drain & fill would be better than nothing, for now. Post here after the first one and let us know if you notice it shifting better.