Hi all. As the title suggests, I’m wondering about swapping transmissions in my D6C. 

My D6C is a 17R is a six speed direct drive.  Several years ago I put a blade on it and for the most part it works ok.  My biggest problem is that the six speed has too fast of reverse. 

First gear forward is plenty slow, but you don’t have reverse in that gear.  Second gear forward is your slowest reverse.  This is fine on the level, but in my area, level doesn’t happen much.  If you’re pushing downhill and need to backup, you use about all it’s got to do so. It’s hard on the clutch, and you can get yourself in a real jam if you’re not careful. 

Is it possible to swap a five speed into my 17R? Does the five speed have a slow reverse?   Would the ring gear also need swapped out?   

I’m well aware this would be lots of work, the tractor is in excellent shape, so it’s worth doing if possible.  

thanks for any insight

BP. 

Hi, Bruce P.
I have never seen that shift pattern in ANY DD machine that I have ever encountered. I am wondering if it is an AG variant.

To the best of my knowledge, all the 5-speeds have reverse on 1 through 4 and not on 5 with 1 through 4 in the 'H' pattern and 5 the outlier _ 1st slot - 1 + 2, 2nd slot - 3 + 4 with 5 off the the right.

I'm no 'ex-spurt' but I can't see any reason why the 5-speed wouldn't just 'plug' straight into the clutch just like your 6-speed.

Just my 0.02.

Thanks Deas.  The 17R was indeed an ag tractor. I farmed with it several years before adding the blade from a 10K that was being parted out.  

I’ve seen older D6C farm cats (not sure about the prefix) that had five speeds.  I suppose I could figure out what prefix those are and start looking in the parts books and see if things like the gasket between the tranny and bevel gear case are the same.  That would tell me if the bolt pattern is the same.  I can’t see Cat making a special case for a low production ag tractor, but I stand to be corrected.  

BP

The SA "Special Application" ag tractors had that shift pattern.  My D6D SA has it.
 

  Bruce Try the Quinn Cat parts depo in Fresno they deal in used parts. Should have the info you need and might be able to get you the parts. Being a cat dealer they should be able to look it up for you. Good luck Skinner

I'll check my direct drive D6c...that pattern looks strange...maybe i'm seeing things...

Do the Direct Drive transmissions have a drop box like the powershift transmissions? If so, maybe there are different gearing sets for the drop boxes.

Wombat

my D6c 99j series trans is how Deas says...so you do have a different duck...

Hi Neil. I’ve looked at the tranny schematic in the parts book.  I can’t see a way to change the gearing at all.  I haven’t looked at different ring and pinions.  You’re right, if I had a higher ratio, I’d be able to leave the tranny alone.  I’d loose top speed, but I don’t need to go 5.6mph anymore.