Dorman trans pan with drain plug-thoughts?

[cnj]

Hi. Getting ready to do a trans fluid drain and fill (probably 3 cycles of it), and change the filter as well. The truck has 150K on it (I just got it 3 weeks ago). I don't think the trans fluid has ever been changed. It is reddish-brown and smells burnt. The good news is the trans seems to be working just fine. Seeing how I really don't like ATF baths, I only want to remove the pan once. I am thinking of installing a trans pan with a drain. Anyone used the Dorman before? Link: http://www.dormanproducts.com/itemdetail.aspx?ProductID=77843&SEName=265-831
The truck is a 1998 Mazda B3000 4x4.

 

[RonD]

Welcome to TRS


Since trans fluid doesn't need to be changed very often, like engine oil, a drain plug is just another hole that can leak, in my opinion.

I think money would be better spent on a second trans cooler, and just get a bigger wider container to catch trans fluid when draining
All automatics should have a second trans cooler, period, car or truck.

The color of current fluid is from running hot, now this can be caused by slipping bands but you said trans is works fine, so it was obviously running hot for long periods.

Trans fluid should not get above 200degF, under 185degF is best, Engine coolant temp in lower(or side) radiator is 170-180degF, where current trans cooler is located.
That doesn't give you alot of cooling for trans fluid especially when under load, like driving up a long grade, no trailer just the vehicle.
As load increases engine temp increases so radiator temp goes up, and trans fluid temp also goes up with load, soon trans fluid is above 200degF and that's when it starts deteriorate, discolor.
Second, air cooled, trans fluid cooler lowers it by 10degF adding miles to trans life, best $60 to $100 you'll ever spend

Trans temp chart here: http://myautomatictransmission.com/images/transmission_failure_chart.jpg

 

[cnj]

Thanks, and agree with the thoughts on adding a trans cooler, and my truck already has one that looks like it came factory (I think the 4x4/auto trucks got trans coolers along with larger capacity pans). Looks like I'll order the pan I linked above and give it a shot. Can't go wrong for $45.

 

[RonD]

Yes, second air cooled trans cooler was an option or included in some packages.

But doesn't sound like it is working very well, ATF will get a bit brown with age but no burnt smell, that's from overheating.

Since you are "flushing" with a few ATF changes in a row, I would blow out the cooler lines, if possible backwards(back flush) against normal flow, get all the gunk out to give best cooling.

On the 4R or 5R(or A4LD) transmission the bottom cooler hose is OUT to cooler, top hose is IN from cooler

 

[cnj]

Thanks!!!

 

[adsm08]

Personally, I like drain plugs on things.

 

[Doofy]

I, at times, get a little anal about drain plugs loosening up. I clean the edge of the plug and the immediate area around the plug with metal prep cleaner and add a couple dabs of silicone. Certainly easier than adding safety wire or worrying. You can also buy drain plug kits and add your own.

 

[RonD]

Leak = escape as through a hole

Less holes = less leaks, simple math

Oil pan drain plug is just another possible leak point, but a necessary evil because of frequent, 3,000 mile, oil changes.

differentials and automatics need less frequent oil changes, so one less hole = one less leak point.

 

[cnj]

Just closing the loop on this. What a great mod! It was really sweet to be able to do several drain and fills with just the loosening of a drain bolt. The pan itself appears to be a high quality piece, at least equivalent to the stock pan. Well worth the $50.