ATF change interval - Do you stick to the OE spec ?

[3930dave]

I tend to run into this more so in real-world discussions than on TBN, but wanted to ask a wide audience.....

Plenty of people around here seem to really stretch out, or ignore totally, the Manufacturer's specified change interval for Automatic Transmission Fluid in road-going vehicles.

So I guess my question breaks down into 2 categories.....

1a) Do you stick to the OEM spec change intervals ?

1b) Do you deliberately modify the interval and why ?

1c) Do you just drive till something happens ?


being TBN, a second question also comes to mind.....

2) How would you contrast your thinking about change intervals for your off-road HST transmissions ?

Meaning - are you more likely to stick to a specified HST change schedule, than the ATF one for your car/truck ?

Rgds, D

 

[Gary Fowler]

On my cars, I generally stick with the change recommendation. I just recently had the 100K change done on the wife's SUV along with spark plugs and fan / alternator belt. This was the recommended change interval. I change motor oil when the computer tells me to but usually I don't let it run down to 0%. I change it at no less than15% of life span per the computer. This is usually about 7K of mileage.

On my tractors / lawnmowers etc. I generally do the changes more often. For instance, I changed the transmission fluid and filter on my ZTR mower at 60 hours rather than the 100. Most other oil changes are yearly because I don't get the hours needed for the recommended change intervals.

 

[davesl708]

I stay pretty much to the OEM schedule on fluid changes. They designed it and think they base the schedule on what will make their product perform best and keep customers happy.

 

[crashz]

1b)

I had a F150 that was sensitive to worn fluid. It would shudder when the ATF had more than 20K miles on it. So I changed it every 15K miles and it shifted well for nearly 200K miles. When I traded it, the truck ran as good as the day I bought it.

From then on, I was a big fan of keeping fresh transmission fluid in my vehicles. My previous trucks have all had fluid and filters changed in a similar manner. Usually once a year and/or every 20K miles I drop the pan and change the filter. The fluid in the pan gets dropped every other engine oil change. As I get older though, the really maintenance heavy stuff occurs more in the summer than winter, so these things are becoming more calendar based .

2

I don't rely on my tractor or SS for an income and they get very few hours per year, so trans and hydraulic fluid gets changed when its most convenient for me. Both are due for service. These are modified from the mfg recommendations too, but I try to stay pretty reasonable and unfortunately my budget palys into these more than on my vehicles.

 

[3930dave]

We inherited an older Civic. The impression I had was that the relative had kept up with fluid changes.

First good cold snap that hit the first Winter we had it, I could notice the delay in engagement at cold start, when shifting into D. Changed out the fluid (it was definitely due) with synthetic - presto - much happier transmission.

Agreed.... some tranis will readily demonstrate degraded behaviour with old fluid. As most who hang out here know..... just because it "seems" to drive fine, it doesn't mean that old fluid isn't taking it's toll....

A lot of people can't be bothered to read the Maintenance Schedule, despite putting big $ into a vehicle...... Where this gets even worse, IMO, is the range of ATF intervals across the industry..... I checked out a Kia car for somebody recently, it was only 30k, and that's in km. Last time I checked VW's DSG, it was only around 40k, again, km.

Even somebody with good intentions, if they are used to much higher intervals on say a Ford or Chev, may not even crack open the Owner's Manual on one of the above to check until well after 100k.

Rgds, D.

 

[3930dave]

On my cars, I generally stick with the change recommendation. I just recently had the 100K change done on the wife's SUV along with spark plugs and fan / alternator belt. This was the recommended change interval. I change motor oil when the computer tells me to but usually I don't let it run down to 0%. I change it at no less than15% of life span per the computer. This is usually about 7K of mileage.

On my tractors / lawnmowers etc. I generally do the changes more often. For instance, I changed the transmission fluid and filter on my ZTR mower at 60 hours rather than the 100. Most other oil changes are yearly because I don't get the hours needed for the recommended change intervals.

Good point on the smaller stuff Gary.

I checked the oil level on my newer generator today; on that one, you can partially see into the sump area. Only 15 hours on the oil, but given how dark the oil is, I'm not going to take it out to 50 hours. Even on a restricted budget, it's not like these small sumps cost much to service.

I do know that dark oil often still works well..... I just sleep better with it gone :zzz:

Rgds, D.

 

[newbury]

I believe in "Trust but Verify".
When I got my F350 (used) most people advised "stick to the OEM interval". Ford recommends changing engine oil (15 quarts)/filter every 3,000 miles. That's 1 quart every 200 miles. Since I didn't want to have to use the block heater much and occasionally go to Vermont/New York in the winter I wanted to put in Rotella T6, which runs $5 to $6/quart. Plus it's much more effort to change the oil than to not change the oil. So I put in the T6 and started getting used oil analyses.
I gave up after 18,000 miles and 3 great UOA's. I had a 3,000 mile trip coming and figured I was pushing the envelope.
My transmission oil was doing fine at 150K, but I changed some anyways. My driving habits are slow towing, long drives at 65, I think that helped.

My tractors are similar. But they don't get much use.

My M4700 has probably gotten 150 hours on it in 2 years and it was changed shortly before I bought it in 2013. At this rate I'll check the hydraulics with a UOA in maybe 2 years. I definitely don't plan on changing 10.5 gallons of Super UDT (about $200) annually for a tractor with light usage kept inside a shed in Mississippi.

So trust but verify, check your fluids visually often, get a UOA occasionally.

 

[DEWFPO]

I tend to run into this more so in real-world discussions than on TBN, but wanted to ask a wide audience.....

Plenty of people around here seem to really stretch out, or ignore totally, the Manufacturer's specified change interval for Automatic Transmission Fluid in road-going vehicles.

So I guess my question breaks down into 2 categories.....

1a) Do you stick to the OEM spec change intervals ?

When it comes to ATF in on the road vehicles, I have learned over the years that the OEM recommendations for changes are detrimental to the life of the transmissions in some cases. Many say "never change" or have 100K service intervals. I won't go into all the details but I have found that, depending on particular trans/vehicle and driving conditions, you need to change out (at least a pan drop and replace) if not a complete fluid exchange (NOT A MACHINE FLUSH) at half the OE interval if you want the trans to last as long as the engine. ATF is pretty cheap and it pays off. Synthetics are best here.

1b) Do you deliberately modify the interval and why ?

A properly maintained and driven automatic trans can last 350K miles depending on manufacturer and use.

1c) Do you just drive till something happens ?

Never, Not if I can help it.

being TBN, a second question also comes to mind.....

2) How would you contrast your thinking about change intervals for your off-road HST transmissions ?

For off-road equipment, I stick to OEM recommendations because they are usually based on hours of operation and a certain expected level of operation/abuse. I don't get the feeling tractor manufacturers are trying to sell you a new tractor every two years or when the warranty is up. But I always do use synthetic fluids here.

Meaning - are you more likely to stick to a specified HST change schedule, than the ATF one for your car/truck ?

Rgds, D

DEWFPO

 

[3930dave]

I believe in "Trust but Verify".
When I got my F350 (used) most people advised "stick to the OEM interval". Ford recommends changing engine oil (15 quarts)/filter every 3,000 miles. That's 1 quart every 200 miles. Since I didn't want to have to use the block heater much and occasionally go to Vermont/New York in the winter I wanted to put in Rotella T6, which runs $5 to $6/quart. Plus it's much more effort to change the oil than to not change the oil. So I put in the T6 and started getting used oil analyses.
I gave up after 18,000 miles and 3 great UOA's. I had a 3,000 mile trip coming and figured I was pushing the envelope.
My transmission oil was doing fine at 150K, but I changed some anyways. My driving habits are slow towing, long drives at 65, I think that helped.

My tractors are similar. But they don't get much use.

My M4700 has probably gotten 150 hours on it in 2 years and it was changed shortly before I bought it in 2013. At this rate I'll check the hydraulics with a UOA in maybe 2 years. I definitely don't plan on changing 10.5 gallons of Super UDT (about $200) annually for a tractor with light usage kept inside a shed in Mississippi.

So trust but verify, check your fluids visually often, get a UOA occasionally.

I've spent (a scary amount of) time on BITOG, reading UOAs for motor oil. This Winter, I should probably change things up a bit, and read up there on ATF reports....

Even after punching up my ATF technical knowledge a bit, I think I'll find that the same problem remains..... ATF fluid is inherently hard to assess visually - in this respect I'm thinking compared to motor oil.

I bought a used truck a few years back. After my initial look-over went OK, I had a pro-wrench friend of mine check it out, specifically the trani - he gave it a thumbs up, noting that the fluid on the stick was a good pink colour, with no burnt smell.

He was right making that call (knock wood, trani is still working), but when I pulled the pan I found a surprising amount of black sludge sitting in the pan.

The real killer problem is sludge coating the transmission cooler... heat transfer rate is going to suffer.

The conclusion I've come to with ATF is that by the time it "looks" bad on the stick, you are way, way beyond where it should have been changed.

Rgds, D.

 

[3930dave]

DEWFPO

One buddy I know made a point of frequently changing the ATF in his work van.

Smart move, as that trani was probably somewhat under-designed to begin with, and in his trade, those trucks rarely saw anything below MAX GVWR.

I wish more light-vehicles took Saturn's approach.... I really like their spin-on external ATF filter.

Rgds, D.