Baldwin BT839 Transmission Filter Cut Open

[Pyrotechnic]

This is a Baldwin BT839 used on an Allison AT545 automatic transmission in a school bus. According to records that came with the vehicle, this filter was installed in 2003, and stayed in service for about 40,000 miles until recently.

Looks like the typical clutch material found in the pan of transmissions that have no external filter.

Thick coil spring and a one piece bottom cap.

Thick gasket for the top seal. Still soft and pliable.

Pleats are a little curvy where they bonded the ends of the media.

Pleat spacing is OK otherwise.

Some destruction. Looks like a well made filter and I didn't find any holes or tears in the media.

Overall it seems to have lasted well, considering 16 years and 40K miles.

 

[bullwinkle]

Not bad, but I would think a Baldwin would hold up a little better. I have a few B2-HPG ones that I'm going to use as transmission filters, hope they do better than that one did.

 

[JohnnyJohnson]

Originally Posted by bullwinkle
Not bad, but I would think a Baldwin would hold up a little better. I have a few B2-HPG ones that I'm going to use as transmission filters, hope they do better than that one did.


What Bullwinkle said.

 

[JHZR2]

Curvy pleats are common in many applications, but disappointing.

 

[Chris142]

Could the pleats expand when they get wet/ oily? Cause them to bend like that?

 

[Pyrotechnic]

Originally Posted by bullwinkle
Not bad, but I would think a Baldwin would hold up a little better. I have a few B2-HPG ones that I'm going to use as transmission filters, hope they do better than that one did.


I agree. I'm not thrilled about the how the media was curved/twisted, but I also can't see any evidence that the filter had failed and was letting particles through.

If you want a sturdy element, I was very impressed by the Wix XP that I cut open. The wire backing makes a big difference.

 

[bullwinkle]

Originally Posted by Pyrotechnic
Originally Posted by bullwinkle
Not bad, but I would think a Baldwin would hold up a little better. I have a few B2-HPG ones that I'm going to use as transmission filters, hope they do better than that one did.


I agree. I'm not thrilled about the how the media was curved/twisted, but I also can't see any evidence that the filter had failed and was letting particles through.

If you want a sturdy element, I was very impressed by the Wix XP that I cut open. The wire backing makes a big difference.


I'm just not crazy about the smashed section of pleats, that's reminiscent of the bad old Fram days (mainly PH16s) when they didn't put enough media in them. Not fatal, just looks like it was lucky it didn't split.

 

[Sayjac]

Originally Posted by Pyrotechnic
...Overall it seems to have lasted well, considering 16 years and 40K miles...
I'd agree. A cellulose media filter in service since 03, I don't think I'd expect much better. Even more so since you note no tears. Yeah the media is wavy, but considering the time not unexpected imo. And wavy media generally, mostly an aesthetic thing. I don't like the one concave opening pleat area, but with that length of service could be a main contributor.

16 years of service, average ~2500 miles per year. The implies either lots of short tripping and/or lots of sitting undriven. Moisture/condensation tougher on cellulose media than syntheic.

Thanks for c&p.

 

[Pyrotechnic]

Originally Posted by Sayjac
Originally Posted by Pyrotechnic
...Overall it seems to have lasted well, considering 16 years and 40K miles...
I'd agree. A cellulose media filter in service since 03, I don't think I'd expect much better. Even more so since you note no tears. Yeah the media is wavy, but considering the time not unexpected imo. And wavy media generally, mostly an aesthetic thing. I don't like the one concave opening pleat area, but with that length of service could be a main contributor.

16 years of service, average ~2500 miles per year. The implies either lots of short tripping and/or lots of sitting undriven. Moisture/condensation tougher on cellulose media than syntheic.

Thanks for c&p.


That is correct. This school bus came from a small town and it was a floater bus. Only used when the primary buses were down for repair/maintenance. The AT545 is a demanding application in terms of fluid and filtration with a high flow rate and high temperatures compared to light duty transmissions. A synthetic filter would have been worth the extra cost in this case.