I have a 08 Sedona with 113500 mi. I completely changed the transmission fluid at 84000 mi with Valvoline Max Life Full Synthetic. I changed all fluid by disconnecting trans line going to transmission cooler. The Valvoline claims it meets the Kia SPIII requirements. After changing, the transmission seemed to run fine and shifts were less noticeable. So far have 30,000 mi with new fluid.
Recently I've made 4 trips of approximately 400 mi each. Vehicle runs fine and we drive at approx 75 mph with occasional 80mph. After stopping for break and fuel at about 225-250 mph. We start out again and shortly after driving, 5-10min, the CEL comes on. The CEL came on all 4 trips. Originally I thought I had code for overfilling fuel. Two times I was able to get code read after the trip and it's code P0741 for a torque converter solenoid stuck off.
The code only seems to come on when restarting highway driving after a long distance, stopping, then starting highway driving again. Before my last trip, I drove on highway at 80 mph for about 20 min to see if the CEL would come on, but it didn't.
Despite the code, the vehicle ran fine, downshifted when appropriate, accelerated up hilly terrain.
Should I have the torque converter lockup solenoid replaced? Is this a costly job?
Thank you in advance for your help. I'm trying to get vehicle to 160,000 mi. I hope to only have 1 child in college by then.
Hello Sirdeeker the transmission fluid change at 84k may have helped reduce the amount of friction material in the torque converter fluid but it will have also released some of the sludge settled around the valves etc.
Check your fluid level carefully Exactly as handbook .
If correct fully drain and see how much short of total the box holds. This gives amount of solid sludge still in box.
Refill with fresh fluid. As per handbook.
The problem with sludging is quite common since asbestos was banned in materials. A few specialists do a high pressure flush to remove sludge but can loose work so not many.
Using the first change as flush works with second change 6 months latter.
Particularly second change should be done hot after run so sludge does not settle. The second change you will be more familiar with and will be safer doing it hot.
Thank you very much for the quick feedback. I have just a couple of questions:
1. Should I drain the transmission fluid using the drain plug or by draining at the transmission cooler? Draining at the transmission cooler I kept filing as the tranny pumped out fluid. Using clear tubing I could see when the fluid changed from brown to bright red.
2. When flushing, should I continue to use the synthetic ATF fluid or go back to the OEM SPIII? If I should use the OEM, can I mix the synthetic and OEM, using the drain plug for draining I would have to mix if not for a short while.
3. Lastly, any idea why the CEL only comes on after the vehicle stops then restarts on the trip? That is puzzling to me. For 200-250 miles no issues, stop for fuel for 15-20 min then restart and the code shows up.
Hi if you are happy draining at the transmission cooler it ensures as much fluid is drained as possible leaving nothing trapped. But the drain plug should be removed and torque box allowed to drain before pumping out rest of system.
The answer to the restarting after long run may be down to the fluids and there behaviour with the friction sludge.
Since your box was initially designed friction materials have changed and fluids also have. A few gearbox specialists have found ways of improving the performance of the torque converters by modifying the holes and valves in the assembly .
Here is a website in UK that specialises for reference . Kia Gearboxes Archives - Automatic Gearboxes - Gearbox Rebuilding Experts
The information on their sit is helpful . .
The sensors feed back to ECU and rapid changes can register as fault but ECU should cancel fault as it recalibrates.
Mixing is not recommended. negates advantages of fully synthetic.
I would stay with same fluid one of top 3 Miller Oils is alternative .
I am sure if you drain and pump out what you have in the system now this will complete an equivalent flush .
Your best option is to keep car going as long as possible with clean fluids making sue the fluid cooler fins are clean and have no air restriction. Then when time comes you can decide if you want a reconditioned torque converter fitted.
So I decided to do a drain and fill and following Jeff's great advice I drove the vehicle to warm it up before the drain and fill. I decided to check the fluid level while warm (Idling warm in neutral)and did not see any fluid showing on dipstick. I checked the level twice because I measured the fluid level a month or so ago and it was fine and I have not had any leaks.
I then drained and measured the fluid removed and had just under 4 quarts removed. I refilled the transmission and it took about 12-14 more ounces than I removed to fill to the dipstick mark.
Just prior to my trips, I had a mechanic replace the driver side half shaft. Could it be I lost that much fluid and it wasn't replaced? Would this cause the P0741 code? I also noticed after the axle was replaced, I often would hear a slight 'clunk' when the vehicle was put into reverse to back down our driveway. I don't recall hearing it before the axle replacement. I assumed there was a bit more play in the aftermarket half shaft but I don't hear that noise anymore after the correct fill level was achieved.
Could this P0741 code be due to just low fluid level? If it's that sensitive, why don't the OEMs have a low transmission fluid level light?
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