Max temps transmission and pyro, and max boost?

[MojaveJoe]

Used to know this info, but us older fellas tend to become historically challenged (poor memory) as we age *LOL*



So I'll ask you smart guys out there this question one last time and write it down in my manual for posterity Then I will go set the alarms on my X-Monitor again.



What would be the maximum "sustainable" numbers for



1) Pre turbo (cyl 456) pyro temp

2) 48RE trans fluid temp

3) Turbo boost



Im looking for numbers, above which one would want to back off the throttle after 5-10 seconds.



Thanks,

Joe

 

[SRadke]

Pyro 1250°

Trans Approx 240°

Boost, won't be a big deal but over 50 psi will be pushing the stock head gasket.

 

[wsurf]

SRadke, I'm not an expert and this pertained to my old Ford with the E4OD trans, but I would start sweeting bullets if my transmission temp. would hit 215F, unless it was up a hill and I knew it would cool down on the backside. Can the 48RE take more heat, 240 seems high?

 

[KLockliear]

1. 1250*F or as hot at it will get on a hard pull in stock form. Many of these trucks will make almost 1400*F stock, so if Cummins and DC are okay with it, so should we be.



2. Depends on where you are picking up the temp from. From the trans pan (like with a Mag-Hytec unit), 210 for conventional oils, 230 with synthetic. In the cooler line somewhere just outside of the front pump - 250*F with conventional, 275* w/synthetic.



3. Your stock turbo is efficient to the high 20#'s of boost. An aftermarket turbo can go above that. Limits of the head gasket with the 17. 3:1 motor will be around 54-55psi.

 

[SRadke]

Thanks for the clarification Kieth. I should have mentioned that part about the stock turbo too.



-Scott

 

[MojaveJoe]

Thanks guys,



Think I will set my alarms on the X-monitor at 1250 pyro. and 27 boost.



Still unclear about trans oil temp. Im picking up the signal from the 48RE's sensor wire. Any idea at what temp Dodge has the warning bulb set to light up? Or where the OEM sensor is located?



Joe

 

[KLockliear]

The Dodge warning light comes on at like 280* I believe. Way too hot in my opinion.



Again, go see how hot the truck will get while stock, and set the upper limit to that or 1250, whichever is higher.

 

[DWordinger]

The 2003 Shop Manual says the light comes on at 135°C (275°F).



It also says "The PCM prevents engagnment of the converter clutch and overdrive clutch, when fluid temperature is below approximately 10°C (50°F).



"If fluid temperature exceeds 126°C (260°F), the PCM causes a 4-3 downshift and engage the converter clutch. Engagement is according to the third gear converter clutch engagement schedule.



"The overdrive OFF lamp in the instrument panel illuminates when the shift back to third occurs. The transmission will not allow fourth gear operation until fluid temperature decreases to approximately 110°C (230°F). "



Anything over 220°F seems hot to me.

 

[DWordinger]

I forgot to add the probe measuring these temperatures is in the governor immersed in the automatic transmission pan. If you want to compare what you are monitoring to these values, you need to measure fluid temp in the pan, not in the cooler line.

 

[MojaveJoe]

talked to a tech

My dealer tech contacted Dodge and found out that 260F trans fluid is too hot and will cause a downshift (as my friend DWordinger has pointed out). Also that the temp probe is inthe pan near the ID tag on the trany.



I think I will set my X-monitor at 250F and see if I ever reach it. Yes, 250 is pretty hot but towing 12K in 100+F air temps like I may be doing this summer in the desert will not be so far fetched. Plus I will get to see how good those dual fluid coolers work Also I can down shift myself if necessary, instead of waiting for the flash point and computer downshift. After a good hot tow I will know for sure how hot the pyro and trans will get stock, then I can adjust my settings from there.



For now my X-Monitor Alarm Settings will be Pyro 1200, Boost 25, Trans 250.



Thanks to all for their insight. Your input helps give me more confidence in my final alarm settings, and ultimately a less stressful towing experience.



Regards,

Joe