Transmission Fluid / Fuel Rail Pressure and "Normal" Operating Limits

[Clayboy]

I am replacing my transmission pan and installing a transmission temperature gage; interested in any recommendations for transmission fluid (science vice personal preference is always appreciated). Also, since I don't know what right looks like, what would be considered the "normal" temperature range the the transmission? Have a fuel rail pressure gage installed already, again, I don't know what right is supposed to look like. Thank you!

 

[cerberusiam]

ATF+4 for trans fluid and change on recommended intervals, 20-25k if towing a lot or 30-35k normal driving. There is no compelling reason, scientifically or fiscally, to use anything else.

Transmission temps will vary on probe location, usage, and ambient temps. In the hot line, which I prefer for usability, given a warm engine 140 to 240 is all I have ever seen for min an max. That is in ambient temps below zero to 110 in the desert. Normal cruising empty or loaded in OD with lockup shows 160-190 depending on ambient temp and load. In stop and go traffic 190-220 is normal for all conditions. When I start seeinf 220 I change driving habits and go to manual gear selection and lockup. Highest temp I ever saw was 240 and purposely did that to see how high and fast it would go in fluid coupling. It does not take long on steep grade with a load and slow speeds to reach that. Note that I have a highly modified transmission to address all the stock cooling problems and a better TC to address the NVH stock build. YMMV.

Ypou don't say what year truck oyu have so that effects the rail pressures. For the 04. 5+ trucks; idle should be around 6500 psi +/- 200 psi. Absolute max would be 23. 5k with arounf 20-21k normal for engine load less that 70%. Empty you have to work to get max load and RP and it is not easy to do, loaded it will be easier. Cruisng 17-19k is normal range.

For the early models take 1500 psi off the idle and 2500 psi off the cruising and max to be in the ball park.

 

[Clayboy]

Mine is an 05 3500 SRW 2wd. I am currently reading 8000-8500 psi of pressure. Thank you for the response.

 

[cerberusiam]

I am currently reading 8000-8500 psi of pressure.

That is high for idle. Might be the gauge also, not all gauages read the same. Check your cruise and max pressures to see if they are reading higher thna normal also.

 

[Clayboy]

That is high for idle. Might be the gauge also, not all gauages read the same. Check your cruise and max pressures to see if they are reading higher thna normal also.

At a steady 70 MPH, I read 18,500 PSI +/- 500 PSI (not towing).



Thank you for the info!

 

[cerberusiam]

Cruise pressures sound normal, idle still sounds high. Usually 6500-7000 psi is normal on that year.