How hot is too hot for Mercon V ATF?

[3800Fan]

I had my 4t65e rebuilt a few months back and the rebuilder decided to put Mercon V in the transmission.

I recently got torque pro and a bafx scanner and my Trans Temps have been as high as 180-200 degrees on 70 degree days.

I'm worried I may burn up the transmission as I'm used to dex 6.

Any info on this fluid?

 

[3800Fan]

Let it cool down for 20 minutes, then went for a 10 minute drive.

 

[demarpaint]

How long did it take to get to 200F? 170-220 or so is considered normal operating temperature for an automatic transmission.

 

[BlueOvalFitter]

I wouldn't feel good with anything over 180*.

 

[3800Fan]

How long did it take to get to 200F? 170-220 or so is considered normal operating temperature for an automatic transmission.

Pretty quick. I drove it about an hour, parked it 2 1/2 hours, came back and on the drive back it hit 200 degrees. Maybe 20 minutes.

I'm thinking about taking it to Jiffy Lube and having a fluid exchange service done on it for Dex 6.

 

[Lubener]

Seems a bit high to me. I hate to think what temps could go to on a really hot day. I don't know why he used Mercon V? He should have used DEX 6.

When I had my Buick with a 4T60E, I added a cooler in front of the condenser. It made a big difference. The 4T60E and 4T65E are weak transmissions to begin with and won't take much punishment.

 

[demarpaint]

Pretty quick. I drove it about an hour, parked it 2 1/2 hours, came back and on the drive back it hit 200 degrees. Maybe 20 minutes.

I'm thinking about taking it to Jiffy Lube and having a fluid exchange service done on it for Dex 6.

For normal driving, no traffic 70F outside, that's a little hot, not terrible, yet. Is the transmission properly filled, not over or under filled? Hard to tell from the picture, not knowing when you checked it and how? What does the guy who did the rebuild think? And why Mercon V? I'd certainly ask. How about a warranty?

 

[tmorris1]

Isn't is going to be within a few degrees of the engine temp since they have a cooler in the radiator?
I don't know why he would have put in Mercon V into a GM?

 

[3800Fan]

For normal driving, no traffic 70F outside, that's a little hot, not terrible, yet. Is the transmission properly filled, not over or under filled? Hard to tell from the picture, not knowing when you checked it and how? What does the guy who did the rebuild think? And why Mercon V? I'd certainly ask. How about a warranty?

When the pulled the dipstick tube out it was sitting just under the full line. It ran up the stick when I laid it down.

 

[3800Fan]

Isn't is going to be within a few degrees of the engine temp since they have a cooler in the radiator?
I don't know why he would have put in Mercon V into a GM?

According to the internet Mercon V is the same spec as Dex III but the dipstick says Dex 6.

 

[demarpaint]

When the pulled the dipstick tube out it was sitting just under the full line. It ran up the stick when I laid it down.

I'm just throwing out questions. Did you follow the proper procedure the mfg. wants for checking the ATF? Some transmissions are checked in Neutral, others Park after a drive allowing it to idle on level ground before pulling the stick. I'd be asking the guy who built it a lot of questions.

 

[3800Fan]

I'm just throwing out questions. Did you follow the proper procedure the mfg. wants for checking the ATF? Some transmissions are checked in Neutral, others Park after a drive allowing it to idle on level ground before pulling the stick. I'd be asking the guy who built it a lot of questions.

Yes I did. Shift through all gears, stop on neutral, check trans fluid.

 

[thastinger]

According to the internet Mercon V is the same spec as Dex III but the dipstick says Dex 6.

Mercon and Dex3 are the same, mercon V is different.
Several fluids are now sold as Dex/Merc but that doesn't include merc 5
Most transmission places use some sort of "universal" fluid, CAM2 makes a popular one.

 

[tmorris1]

According to the internet Mercon V is the same spec as Dex III but the dipstick says Dex 6.

Dex III is equal to Mercon
Dex III\Mercon is not equal to Mercon V.

 

[HyundaiAbuser]

Dex III is equal to Mercon
Dex III\Mercon is not equal to Mercon V.

Mercon V is back specced for mercon so if mercon = dex 3 then mercon V should be suitable no?

 

[ripcord]

It's back spec'ed by Ford for Ford products using Mercon. I think I would switch to Dexron VI which is happy as a clam running at 200f and call it good.

 

[CKN]

It's back spec'ed by Ford for Ford products using Mercon. I think I would switch to Dexron VI which is happy as a clam running at 200f and call it good.

Yes...Dex 6 has actually been tested up to 285 degrees-transmissions run warmer these days.

I'm waiting for that redone but still 20 years old (data) transmission fluid chart to make an appearance on this thread......

 

[palmerwmd]

I do not think anything over 200F on a auto tranny is good.
Not so much the fluid itself but the seals.
Despite the inline raditor coolers ATF will not be at same temp as coolant as the ATF/coolant heat exhcnager since at the cool spot on the radiator.

If memory serves 160-180F is the proper operating tempt for an Automatik transmission.

 

[3800Fan]

Looks like I'll be getting the flush done.

 

[3800Fan]

Fluid exchange I mean.