Transmission Service
 

Does anyone know if the 4T40E automatic transmission has a drain plug on the torque converter? I want to service my transmission, but I also want to switch to Mobil 1 synthetic.

I'm not sure Mobil 1 can be done with a flushing machine.

Thanks!

Why do you think Mobil 1 Syn could not be used with the machine?

Oh I'm sure it could. I just assume that it would require alot more fluid, and most places probably don't keep a huge drum of it around. If I had to supply the fluid I would have to buy alot more than I'd need.

Its my understanding that a flushing machine pumps new fluid through the system until it runs clean...

I wouldn't go through the expense of going full synthetic in your tranny unless you just have money laying around that you dont need.

most of the high performance N-bodies (300+ whp) using 4t4X series transmissions are using GM original fluid, stating more issues and problems with using "high-end" trans fluid, like synthetics or Red-line as some examples.

I was told this on another site too. The only reason I wanted to run Mobil 1 was that I figured it would run cooler and last longer. But if everyone has issues with running something other than GM fluid, i'm not really interested in taking that chance. If anything, I could add a cooler to it, but thats not that necessary. Yet. ;)

Anyone know what a transmission fluid and filter change with a flush costs, approximately, at the dealership?

Thanks for the advice guys!

i have full synthetic Royal Purple in my new tranny with no issues.

Did you add it right after a fresh rebuild or did the new transmission come with fluid in it? That might be the difference. I dunno.

adding a cooler to your tranny is ALWAYS a benefit, i have a large cooler on mine and it works wonders, during the winter my tranny runs at aprox 120, during the summer it runs at aprox 180, i will be adding a second rail cooler to drop temps fyrther during the summer. its an inexpensive and easy safety measure for the life of your tranny.

i added the royal purple whenever i did my swap. the new one had factory fluid in it with 40,000 miles.

Yes, but, its my understanding you can cool the tranny TOO much. It does need to be a certain temp to do its jop properly. I might add a cooler in the summer.