Has anyone used the rear test port on the passenger side of the 48 RE transmission for the installation of their trans temp gauge. Are ther any reasons that this would be a good or bad idea? I have seen several posts that mentioned using this port, but none that explained if there were any drawbacks to this method. I have mine installed on the output hose from the trans to cooler which is working fine. I will be helping a friend install a gauge set and thought if this was an acceptable way to install the gauge, it might save him some cash on this job.
Thanks for any input !

 

I used one of the test ports. I would suggest getting the tranny line from Mass diesel and do it that way. I think they want 75-80 bucks. The test port isn't super accurate. I would go for the Mass line or a tranny pan with a port. I always noticed when parking on a incline i would get a better reading. I don't think the fluid is always on the probe in those test ports. My 2 cents !

 

The rear test port on the passenger side is the rear servo test port. The problem is the rear servo only sees pressure (ie. fluid flow) in reverse and manual 1. This won't give you a very good (accurate) reading. The accumulator test port, the one in the middle, sees pressure (and flow) in all but reverse, which is why it's the better of the two. Of course, the best place is in the line running to the cooler, since this sees pressure/flow at all times.

 

I wondered the same thing so I sent an email to ATS. This was their reply:


Tom-
That test port works fairly well. Our first preference is always to have one of the high capacity pans with the tap built-in since that is where the valve body sits, but second choice would be the port you spoke of. Since you have not installed the gauge yet you might check out the pan option:

I put mine there and it seems to work fine. I pull a 10K fiver.