Engine/Xmsn temps??? - Printable Version
+- Newell Gurus (https://newellgurus.com)
+-- Forum: Technical Discussions (https://newellgurus.com/forumdisplay.php?fid=3)
+--- Forum: Drivetrain (https://newellgurus.com/forumdisplay.php?fid=4)
+--- Thread: Engine/Xmsn temps??? (/showthread.php?tid=3741)
+- Newell Gurus (https://newellgurus.com)
+-- Forum: Technical Discussions (https://newellgurus.com/forumdisplay.php?fid=3)
+--- Forum: Drivetrain (https://newellgurus.com/forumdisplay.php?fid=4)
+--- Thread: Engine/Xmsn temps??? (/showthread.php?tid=3741)
RE: Engine/Xmsn temps??? - HoosierDaddy - 09-08-2017
My 1993 is air operated. I have a simple on-off-on momentary switch in the console to operate it. I'm not totally happy with it. It shifts very slow going from R-N-D-3-2-1 upshifting is a bit faster.
RE: Engine/Xmsn temps??? - Fulltiming - 09-08-2017
I find I have to manually downshift on hills or it will drop too many rpm's if left to its own devices. Dean, have you tried increasing the air pressure a little to see if that helps?
RE: Engine/Xmsn temps??? - 77newell - 09-09-2017
Interestingly, despite having the electronic version of the transmission, I too, have to manually downshift or the RPMs drop too low before the shift. The reason in my case is that Newell did not install the link from the TPS (throttle position sensor) to the transmission ECU so that the ECU would know what the throttle input is. I'm told they did this to improve fuel mileage. This has created a bit of an issue for me since I installed Transynd. Sometimes on the 2-3 shift or the 3-4 shift the clutch on the new gear slips until I back off the throttle and the clutch can fully grab. There is valving in the transmission that pushes higher oil pressure to the clutches 3 and 4 whenever the TPS is greater than 60%. The intention of the design is that you get softer shifts with lower throttle and harder shifts with higher throttle. I plan to talk with an Allison dealer to find what solutions are available.
If you have a mechanical transmission there should be an air signal from the air throttle going into the tranny to accomplish this same purpose. It worked on the 77 coach with the HT740.
RE: Engine/Xmsn temps??? - dannymarilyn - 02-04-2021
Dear Newell Allison HT-700 Series Drivers,
After several $$$$ with the local United Engines facility, we've learned that our coach (#277 1991 model) was broken before servicing and United Engines accidently fixed the problem of a low reading transmission temperature gauge. Our VDO gauge reading matches the transmission oil pan temperature very accurately. After the repairs of cleaning the rear mounted radiator, repairing the many oil leaks, engine computer
cruise control and speedometer outputs, I began noticing the transmission climbing to 210° on the first trip out to Newell for new heaters and other work.
Before repairs it rarely reached 140/160° on the road. This was at 65 mph at about 1750 rpm.
Well turn around and a slow trip back to United Engines. They cleaned and flushed the transmission and road tested OK. So on the road again, the transmission temperature begins climbing if I travel over 55 mph. We finally retrieve the coach in January (parts issue, not Newell's fault!) and return the RV to United Engines. After a two hour test drive and seeing 250° in 62° OAT, UE calls Allison. See the attached Allison manual pages.
It turns out for an Allison HT-41 (700 series), the transmission temperatures can be at 300° and easily at 250° continually. See attached pages.
I hope this saves everyone money and worries. The temperature probe is at the output of the transmission feeding into the radiator which is the hottest point in the system. I've never found the transmission manual in our coach.
Happy road miles to you!
Danny
RE: Engine/Xmsn temps??? - ccjohnson - 02-04-2021
Attachment did not come through!
RE: Engine/Xmsn temps??? - Richard - 02-05-2021
Interesting.
Are you going by the gauge on the dash, or are you using VMSPc to read the data?
RE: Engine/Xmsn temps??? - dannymarilyn - 02-05-2021
Dear Guru, The temperatures are from the VDO dash gauge, but we've stopped several times and the IR readings of the transmission pan agree with the VDO indications.
All the best,
Danny
I'm trying to send the Allison attachment again. If it doesn't come through, email me at " [email protected] " and I'll send the pdf file directly.
All the best,
Danny
RE: Engine/Xmsn temps??? - ccjohnson - 02-05-2021
Got it! Thanx Danny!