Deep pans and dipsticks

Now that my trans is installed and everything is working, I have a new question regarding the fill level.

The old trans had a shallow pan and the replacement is a deep pan. Upgrade right? The sticks are different but the fill tube is the same as far as I can tell. Deep pan stick is longer and marked different.  Shouldn't the surface level be the same regardless of the depth below? 

Did anything change with whatever the pickup point is?  If not, I would think it would be the same.

You are filling from the bottom up. You extended the pan downwards. The fill mark is still at the top. The full point is in the same location, just now there is more fluid under it.

The proper fill is based on where the oil level is in relation to the crank.  If you put in a deeper pan, it shouldn't change where the actual oil level is.

Depending on the vehicle, it's possible they made a deep pan to keep parasitic oil off the crank by dropping the bottom of the pan, (same or more capacity, but the oil stays off the crank) but that would be a hyper-tuning/race thing. Most engines rely on thrown oil from the crank in some way.

The old school trick on American V8s was to drill and tap the valley gallery for nozzles that squirted on the bottom of the piston before switching to dry sump systems.

In reply to Curtis73 :

Looks like transmission pan was changed, not engine

Ah... same rule applies.  Dropping the fluid level would mean no increase in fluid capacity.

I have done my own dipstick by cutting one down from a truck and marking it myself.  Just take the pan off and use a straightedge on the pan rail to mark the stick.

So is the purpose of the deeper pan to increase capacity or to lower the level ?

   Depends

I'm guessing it's for more capacity.  The trans is from a newer truck and they all had it. The filter kit is specific for deep pan too.

If you put the sticks side by side, the deep pan has the fluid at a lower level compared to the pan rail. I'm probably over thinking all this.

iceracer said:

So is the purpose of the deeper pan to increase capacity or to lower the level ?

   Depends

Always to increase capacity/cooling.  With a deeper pickup to match, you could theoretically drop the level back to the same capacity, but I wouldn't for two reasons: 1) with more room to slosh, there is more chance of picking up air, and 2) why would you want a lower pan if it doesn't give you the benefit of increased capacity?  Zero benefit with more chance of damage.  I suppose if the OEMs did it, they went through the R&D on the sloshing/air issue and found it not to be a problem, but deeper pan + lower level/same capacity = no benefit.

Are you using the original dipstick tube? If not, is there a possibility the tubes are different lengths, too?

Tube on replacement trans was destroyed. Parts catalog shows same part number for Tubes, but different sticks.

Kaiser/Willys (Jeep) said cut 3/8th in. from the dipstick tube to effectively lower the engine oil level.

If I were doing it, I would use the old tube (since they're the same anyway) with the deep pan and the old stick.  Same top level can't hurt anything.

Due diligence... look up TSBs and recalls for the vehicle in question.  I've seen dumber things where an OEM makes a choice like that, it tests fine in their controlled ASTM tests, then fails miserably in the real world.  Think about Dexcool.  The best intentions...