UOA Castrol/GM Mix - 35K miles

[RedDart]

Here is a recent UOA for my 2002 Chevy Impala (4T65E transaxle). The fluid was a Castrol/GM mix after a pan drop and filter change at 50K miles (severe service interval). The lab used was Titan Laboratories. I have used them for two previous UOAs for this transmission and will include some results and comments for those UOAs to provide a more complete picture.

Total Mileage: 85K
Mileage on Fluid: 35K

Viscosity - cSt 100C: 4.5
SAE Grade - 100C: 10
Fuel Soot - % WT: 0.0
Water/Fuel Dilution/Antifreeze: None
Chromium: 0
Copper: 295
Iron: 106
Lead: 152*
Tin: 8
Aluminum: 6
Silicon: 2
Antimony: 0
Barium: 0
Boron: 94
Cadmium: 0
Calcium: 192
Magnesium: 5
Molybdenum: 0
Nickel: 0
Phosphorus: 407
Silver: 0
Sodium: 9
Titanium: 0
Zinc: 103

Maintenance Recommendations: Change oil and/or filter if not already done. Resample 1/2 normal interval to monitor system. Lead is high.

Summary of 1st UOA at 30,710 miles (factory fill):
Lead was critical (no PPM value provided)
Selected comments: Continue to follow manufacturers recommended maintenance schedule and resample at that time to monitor system condition. Critical lead is from compound used during assembly.

Summary of 2nd UOA at 50,114 miles (factory fill, before fluid and filter change at 50,668):
Lead was critical (no PPM value provided)
Selected comments: Change fluid and resample in 10,000 miles to monitor system. Lead could be from extended fluid change.

I had hoped that the trend of high lead would decrease with the transmission service at 50K. I have some immediate questions: 1) Does anyone know what the acceptable PPM is for lead in an automatic transaxle? 2) Does this level indicate extreme wear? 3) Is this a common issue for GM 4T65E transaxles? and 4) How worried should I be about the health and longevity of this tranny?

My plan is to have the fluid and filter changed this weekend (via pan drop). I am leaning towards using Valvoline MaxLife ATF due to the increased level of additives.

Any analysis and comments are welcomed. Thanks!

 

[RedDart]

This is a follow-up to my post dated 04/24/07. I called Titan Labs and spoke with the lab director (Marina) re: the high lead reading. She said that a PPM for lead below 100 was acceptable. She reviewed my prior UOAs and said that the trend was downward and the PPMs were decreasing. She also said that it takes a long time for the lead to leach out and that it will take several pan drops and filter changes to reduce the lead level due to fluid remaining in the transaxle. The lead is most likely from assembly lube and does not indicate excessive wear or a problem. Whew!

I will still change the fluid as the viscosity level is low (4.5) and the fluid has probably sheared back. I do not know what the viscosity was of the Castrol used. It is currently 7.9 for the Domestic Multi-Vehicle ATF.

I feel better now but still welcome your analysis and comments.

 

[unDummy]

Pan drop is just a partial change. I would definitely get a full flush in there now.
Pan drops(or drainplug) partial maintenance is great if you do it every 10k miles or every year. Anything beyond that is silly and shows in your UOA.

If you want wear to be reduced, you'll have to practice more frequent flushes or more frequent drain/refills. Install a good aftermarket ATF filter to prevent wear that creates wear. You might be suffering from that compounding effect.

 

[RedDart]

UnDummy: I called the repair place that usually does the work I cannot handle and they want to flush the transaxle, lines, and cooler with solvent and add new fluid. I have heard that solvent flushes can be damaging because all of the solvent is not flushed out by the new ATF and it dilutes the fresh ATF. Also, some places that do such flushes don't bother to drop the pan and replace the filter. The procedure recommended by GM is to drop the pan and change the filter and that is what most reputable transmission shops do also. Breaking loose hoses to attach them to a flushing machine is just asking for trouble IMO. I think I will have a pan drop done with a new filter and then use a friends fluid extractor to remove more ATF at a later date and add fresh ATF to further reduce the lead level. Having paid to replace a transaxle on a 1995 Taurus I would be rather safe than sorry.

 

[Cutehumor]

I have a GM 3 speed auto tranny posted on here too. Wear was similar to yours. I would just do more frequent pan drops or flushes and cut the interval down.

 

[unDummy]

No solvents are needed. But, IMO, a flush is needed.
Machines come with adapters so splicing into cooler lines is not an issue.
Install a drainplug if you don't trust the competence level of a machine flush in your area.
OEM filter is a joke.
I also don't care what GM, or any other automaker recommends. This transmission should be flushed.
If you don't want to flush it, perform 5 back to back drain/refills with 5 mile trips in between. Then, continue with a 10k-15k drain/refill made easy by that drainplug. Change the OEM filter every 100k; or replace it now, install an ATF filter kit, and never bother touching the OEM filter again.

Upgrading to a higher quality fluid is recommended.

 

[WishIhadatruck]

My experience with GM 4T60E and 4T65E transmissions is that you get 6.5-7 quarts out with a pan drop and filter change. Much more than many other transmissions so you are getting a better % change with each pan drop. I don't recall what the total fluid capacity is but for these transmissions a flush isn't quite as necessary as some others. I would do multiple pan drops if you don't want to do the flush, 5 might be overkill but won't hurt. The flush would be best however.