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I was wondering if there is a way to look at the 904 and tell if it is a L/U or non L/U. I have an early 80's truck transmission laying on my floor and was wondering. Also do the truck 904's have any Heavy duty parts in them.
I am now towing my Valiant with my 85 D100 with a Lock/up transmission. It sounds like that may not be such a good idea long term. I may want to swap it out for a non L/U one in the near future.
Rick
Early 80s 904 truck transmission will have the wide ratio gearset and will be a lockup transmission. A very few nonlockup 727 slant transmissions were installed in the 80s, but if you have an 80s era slant transmisison form a truck it will be a 904T wide ratio and lockup unit. Be absolutely sure about the year though.I am now towing my Valiant with my 85 D100 with a Lock/up transmission. It sounds like that may not be such a good idea long term. I may want to swap it out for a non L/U one in the near future.
Rick
You could also pull the trans ID number off the pan rail and look it up.
However, the easiest way to identify a lockup unit is to look at the splines on the input shaft:
Lockup on top, non-lockup on the bottom.
However, also be aware that as late as 1986 non-lockup 904s were being produced for trucks and vans sold in California. I used to have a 1986 Dodge van that was built for the California market and it had a non-lockup 904 transmission. The factory service manual even mentioned the fact that only California 904s were non-lockup.
So, check the input shaft to be sure, but it is highly likely that that transmission you have is a lockup and wide-ratio unit.