Hi,

Maybe my question would seem dumb to most R51 owners, but better ask than sorry
Well, this is the first time I own such a huge vehicle with automatic transmission and it feels quite weird to me. In short - it looks like all time slipping a bit, especially when I gas it a bit more.
For example, when in 5th gear on highway, and I push it a bit more, at that moment only revs go up, for example from 2500 to 3100, while vehicle speed did not increase yet. After higher speed is achieved, revs stay at 3100 in this example.
If we'd be talking about manual trans, such a symptom would definitely mean clutch slipping. What about with this one - is it normal, or not?

**EDIT**
Just watched some excellent youtube video about Torque Converter, which is an oil-based turbine-like clutch and that's what auto trannys use instead of clutch. In principle it always "slips" aka looses some torque, except in top gear and above some predefined cruising speed (above 50 mph, for example), when an additional friction plate, simmilar to friction clutch, kicks-in and physically connect engine output with tranny input, which renders torque converter a zero-loose converter (but only while maintaining the above mentioned speed and top gear).

So slipping effect, which I noticed initially, is kinda normal below lock-in speed, anything beyond that should need to be investigated.

I'm a little unclear of what exactly your describing, but it sort of sounds like it's going into passing gear to me. If you gas it and the engine RPM's raise but no acceleration for maybe... half a second or so then you may have a problem. Is it shuddering while coasting?

When it's cool, open the radiator cap and have a look at the coolant. Should be nice and green, if it looks something like chocolate milk then you may have fell victim to the radiator tranny cooler issue.