Transmission temperature gauge moves very little during travel, level road and some hilly terrain using lower gear and retarder.
Mine (98 U320 6 speed) will generally stay put unless it's getting a good workout. Mostly from the retarder on big descents. Up hill not nearly has much provided I don't pull to big a gear. Down shifting is your friend. I monitor the heat through a vmsPC.
The factory gauge doesn't show the retarder temps. When I got the VMSps I found that when the gauge was reading 210 the retarder temp was over 250
There is a huge difference between the gauge on the dash and our VMSps One of the best items we have purchased for our coach dealing with mechanical conditions! On our '98, we never thought we were getting the trans temp that hot when looking at the gauge, boy were we surprised when we added the VMSps to our 2000 coach. These same grades decending down some really steep down grades would see temps up in the 240 to 250 range. Even with Transcend installed in both. Like Bigdog mentioned, down shifting to a lower gear is your friend. Coming up through Utah on Saturday, we watched the temps closely and kept them down by downshifting. Yes, your temps will go up in climbing as well if you are not downshifting to a lower gear. You will see the trans temps go up then. There are some really steep grades out west and if you haven't driven out there yet, you are in for a real eye opener! Rule of thumb, what ever the gear you are in climbing, use that same gear in descending!
Side note: Your weight of your coach has some influence as well with temps in general!
My dash transmission temp gauge reacts to retarder(MD3060R) use immediately. It will go over 210 on just a normal stop from 60MPH. During normal driving the trans temp hangs right with the engine water temp.
Is the VMSps gauge replacing the existing gauge or an an on?
Yes on the downshifting. Better engine compression retardation in itself. Helps some. From what I think I have seen in posts here some of the trans/retarder auto trans downshifting might be not working fully with the brake light disconnect on retarder mod.
That mod is a big plus for me as the ability to use the retarder with the cruise control mostly automates the up and down grade use.
As was posted having the retarder come on down grades does help you notice if you are exceeding the speed limits if set at the limit.
I looked at VDO's gauges offered and can only find the zero to 400 degree model.
The VPMS's trans temp display on the computers screen is more helpful as was stated here.
I tend to use the retarder primarily until getting close to 240 degrees then turn if off and start using the service brakes until the trans temps drop 20 degrees or so then start using the retarder again. Alternate.
Rarely do I need to go slow. Wolf creek pass comes to mind where I did reduce my overall speed substantially. Rare.
The coach and toad at 36,000 pounds combined do use the braking systems harder than normal but well within their limits if you have the brakes in their best condition. Weaker brakes make the retarder work harder.
Same here on all my coaches. I just keep an eye on it. The Allison manual indicates that the top temp for the transmission sump is 250F at which point it inhibits shifting.
jor
Jor do you have a link for the Allison info?