Picture this.

You are climbing an approx 4% grade at 65 mph with the transmission in econo mode. As the coach begins to slow down the transmission down shifts to 5th. Then as the coach approaches 54 mph there appears to be a loss of power which decreases the speed to about 45 mph. The throttle had no effect and at the time of power loss the transmission down shifted to 4th (I think). This power loss lasted until the crest of the hill (a mile or two) then normal power returned or so it seemed. Transmission temperature was in the normal range somewhere around 180 F if I remember correctly. Any thoughts on this problem?

I have been studying the transmission some and am wondering if the transmission defaulted to a secondary shift program for some reason. I'm not quite sure what would cause it to do that but maybe some of you know. I wasn't squared away enough at the time to look for error codes in the transmission electronic controller.

Then, several thousand miles later, approx 100 miles after filling up with fuel I experienced another loss of power. This time it was on a relatively flat stretch of hwy. Again the transmission was in econo mode and speed was about 60 to 65 mph. The power loss brought me down to 40 or 45 mph and the transmission down shifted to 4th and the throttle did nothing. This loss of power lasted for approx 15 miles then recovered somewhat. I don't think it recovered 100% but it wasn't bad. I mentioned filling up with fuel because at the time I thought it was a fuel problem but now I'm not sure. Any thoughts on this problem? If I remember right the transmission temperature was in the 150 F to 170 F range at the time of power loss.

I have since had the transmission fluid changed to Trans-Synd which from everything I've read is pretty good stuff. The filters were changed and the cooler was flushed at the sametime. The mechanic didn't notice anything abnormal when he changed the fluid and filters.

Get your turbo charger checked out.

As Gary indicated, it sounds like a boost issue. First check the air filter. Was boost normal when this issue occurred?

Rusty,

There is no way for me to know if boost was normal as I don't have a boost gauge and by the way what is normal boost? I have read that a boost gauge and fuel pressure gauge are considered by knowlegeable owners to be quite important. I plan to add both in the near future along with an exhaust brake. Any suggestions for the boost and fuel pressure gauge setup and also the exhaust brake. The air filter was new 5100 miles ago and most of those miles were on pavement, but I will check it out anyway. Thanks to all for the expert advise.

Roman,

I am surprised that your setup doesn't already have an exhaust brake on it. In any case, the PacBrake is one of the most common. Their new PRXB model was an upgrade I did on mine from the original PacBrake. However, if you really don't already have an exhaust brake, the other consideration is to have the valve springs upgraded to the 60lb variety - otherwise they won't stand the backpressure an exhaust brake delivers.

If you think you have a turbo problem, I might consider the Banks Stinger package. It also includes a boost gauge and an exhaust temperature gauge - one of the most important gauges you can have if you climb hills regularly.

Not sure what advantage there is to a fuel pressure gauge.

Mike,

Likewise, I was surprised it didn't have some kind of OEM helper brake , but it doesn't. The 1993 36' Barth that I looked at in Arizona didn't have a helper brake of any kind either. And! to make things more expensive the Allision MD3060 transmission I have can't be fitted with a PAC brake for a reasonable price. I was told the model needs to be an MD3060R to make it cost effective.

With regard to the fuel pump gauge. I learned on the diesel ram site that one of the reasons for lose of power and failure of injector pumps is low fuel pressure to the injector pump. I have a 2002 Dodge Ram with the 5.9 cummins and have already experienced one injector pump failure. Hense the comment on the fuel pressure gauge and now that you mention the exhaust temp gauge I remember that recommendation on the diesel ram site too. Thanks for the input.

Roman

EGT monitoring is vital, IMHO - although the "redline" varies from engine to engine, as a rule of thumb, 1250°F is max continuous; 1400°F is borderline disaster.

Next most useful is boost pressure - while it closely correlates to EGT, when that correlation gets odd, something is afoot, such as a dirty air filter.

In any event, I'd not drive a turbodiesel without both. I backfitted my AMG with a VDO EGT system and a S-W boost gauge. I also have, and recommend, a transmission temp gauge; mine's S-W. Knowing what's going on can save many bux.

Thanks Rusty,

It appears that I have a lot more research and work to do in order to get the Barth outfitted properly. I do have a transmission temperature gauge and it appears to work properly. Thanks for the input, I'll keep you posted as to my progress.