Tranny fluid and filter change on older tranny

[wrbrower]

Hello all!

Looking for advice regarding my older tranny and transfer case.

91 XLT 4x4
AOD, no issues, only minor seeps
Electric transfer case, no issues, only minor seeps
I bought the rig at 167K seven years ago from the dealership
It now has 248K
It is a commuter vehicle, barely any towing
1 week a year of 4x4 when it snows
The owner before me had the tranny rebuilt but no details
I have not touched the filter nor added any fluids (I feel bad but it has never complained)

Here are my options:
1- Leave it alone since it works well
2- Drop the pan and wipe it out, swap the filter and fill her back up
3- #2 and dump some home flush stuff in it
4- Have it done and flushed

I am a decent weekend mechanic I don't mind working on the truck.

I have learned that some things require constant tweaking, other things you leave it alone if it isn't broken.

I appreciate ya alls advice.

Cheers, Bill

 

[Opera House]

First, it is an A4LD. Changing the filter won't do anything unless the fluid is extremely nasty. This came with only a metal screen filter that really can't filter out anything but large pieces of gasket. If you change the filter make sure it is a Microfelt type that can filter out some junk. Just ask for a 97, make sure it bolts up all the way with a spacer. Your bolt is too long and will bottom out. Everyone thinks, I've changed my fluid and I'm a good boy. Whatever you find in the pan, there is twice as much gunk still stuck in the transmission. Just as much will be in the pan when you drop it 3 months later. Several pan drops is better than a flush. Is it a good idea? Stuff happens. Regardless, it isn't dirt holding it together. If reverse doesn't have a delay, your seals are probably still decent.

 

[Glacier991]

As usual, Opera House is dead on. He has taken some flack for his position on flushes in older transmissions, but I think he has some excellent points.

 

[aldive]

I, on the other hand, am a believer in tranny flushes, external filters and synthetic fluid.

 

[old mechanic]

I am a firm believer in NOT doing a FULL flush in a tranny (with 80,000+ miles on it)that has never been changed before! If you decide to change your fluid, just drop the pan, change the filter and add fluid as needed. Do this a few times until the fluid looks clean.
Al Dive has a way of doing a full flush that is supposed to be OK. I never tried it.
Check it out with Al Dive if you want to.

 

[wrbrower]

Thank You Everyone!

The reason I asked is I took in an STS I had a while ago and they didn't want to do tranny service (filter flush) on one more than 80K. I think I understand, they probably had a lot of people bringing it back claiming they screwed up the tranny afterwards.

I think I will do a few drain / clean / fill / repeats

Today we get a new heater core, TG it is a '91!

Regards, Bill

 

[wrbrower]

Oh, one more quick question please.

About how many quarts do you expect to come out on a pan drop?

If room permits, maybe I will add a drain plug it there isn't already something there.

Thanks!

 

[aldive]

It will be about 4 quarts if I remember correctly.

Good luck....