Re: Cat 3208 - small???
Reply #37 –
It's a retarder. It's totally silent, makes the tranny temp gauge move like the second hand on a watch when fully applied, and you can physically see the extra housing on the output side of the tranny along with the huge hoses going to the heat exchanger. The "B" in MTB-648 means retarder. Attached is the brochure from my coach book. Notice the max. input power is 250hp - but my engine is 300hp (confirmed from the DDEC printout). I never got an explanation of why FT did that but the tranny does seem to handle the hp without a problem. When I first bought the coach I asked DD if I could increase the HP to 350 and the answer was no. I suspect it's because of the tranny and the cooling system (rear radiator). I think that is why FT moved to the 700 series when they upped the engine power a year later to 350 in the '92 models (along with a side radiator). I suspect the real reason the tranny works in mine is because trannies are actually limited by the torque they can transmit not really the power. The 6V92 puts out 820 ft-lbs verses the tranny limit of 780 ft-lbs. - so it's only 5% over. The HP and Torque ratings are for an engine are without any accessories (alternator, pumps, compressors) so the real torque to the tranny is probably at its limit or lower.
Topic: Cat 3208 - small???