View Full Version : New here

Manx Kat
12-01-2006, 05:40 PM
I am new here and just learning how to use this BB.
I do not own a cat at the moment I have owned 2 in the past. The last being a D7-17a. It was sold 3 years ago after I got sick and was barely able to walk. I have since made a very good recovery and miss my CAT. So I am looking for another one. I found a D8-2U that will be on an auction of a retireing farmer in the spring. I intend to go to see it.
I have a few questions for you experts if I may ask.

1. Does a D8-2U have a wet clutch?

2. What differences are there as to the way they work from the D7-17A(example are the steering clutches hyd assisted )

3. Since not even CAT is perfect do they have any particular weak spots?

I am trying to do some research now so I am better informed by the time I get to see this cat.

D.K. in S.K.

Old Magnet
12-01-2006, 05:58 PM
Hello Manx Kat and welcome.
Happy to hear your are on the mend and needing a little Cat therapy:D :D

The D8-2U did not have an oil clutch until serial #5307-up.
At serial number 5307 they also came with a transmission oil circulating pump.
The 2U series never did have hydraulic assist steering clutches and made due with mechanical spring assist.

Those are probably the only areas of concern but otherwise they are pretty much bullet proof and a fine machine.

Meant to add: They built about 23,500 2U's from 1946-1953.

Delta Dirt
12-01-2006, 10:13 PM
Manx Kat---

I know you are a helluva long ways from Columbus, Mississippi----but just for what its worth, there is a D7 17A and a couple of parts tractors for sale down at Columbus. See the Sale/Trade Forum----this equipment belonged to Johnny Morrison who passed away a couple of months ago. I brought the For Sale info over from the ACME site as a courtesy to his family.

Johnny had been working one of these tractors----apparently the other two are not running. Even got a truck and lowboy in the listing.

I know this would not be feasible for you----but maybe somebody else might notice and give them a call.

Hope you find something to fit your needs close to home----glad to see you up and running and here on the board. I know what its like to not be able to do what you want to do, need to do, and use to do----gets sorta frustrating. Gotta keep moving forward---the world ain't gonna wait on none of us.;)

Good luck---

Delta Dirt

12-01-2006, 11:15 PM
Manx Kat,

I would add that even tho OM is right about the D8 2U having the oil clutch starting with Sn 5307, and was thereafter standard equipment, here were two oil clutch field kits that could be added to the earlier 2U’s in the field. So it could be very likely, you are looking at one that has a field kit installed. If you can get us the Sn of the tractor in question we could research the oil clutch a little further, if in deed it as a oil clutch, and is earlier then Sn 5307.

They were as stated, almost bullet proof and were top of the line in there time. I would check the sprockets with a bar of looseness, as well for any leaks from the finals. I’m sure you having owned tractors in the past you will be eye worthy to other areas of wear.

Keep in touch with the progress of your investigation on this tractor and good luck with it as well as your health.


Old Magnet
12-02-2006, 11:07 AM
Per my parts manuals, if I interpret correctly the oil clutch did not become standard until serial #21,513 but field conversions were available back to serial # 5307.

Manx Kat
12-02-2006, 04:14 PM
Thanks all for the good info. I am greatful to you all.
Yes I am a ways from Columbus BUT if you knew somebody that might haul one up at an price I could afford maybe a backhaul I would be interested.
I will not see this D8 till spring (april or may) so will not have ser# till then.
It will be sold june 23 so I have to wait a while if I am to get this one.
As for the dry clutch I am not very worried I ran a TD18A ( ya I know its IHC but it was painted YELLOW)am I allowed to mention IHC on here:D :p :eek: for years and it had a dry clutch with no problems.
As for undercarriage I think I have a clue what to look for.
Will keep you posted as to how my search is going. might be back with other questions.

12-03-2006, 03:29 PM
I miss read your post, thinking you meant the 2U came out with the oil clutch at Sn 5307.
“The D8-2U did not have an oil clutch until serial #5307-up.” Sorry about miss reading the same, I took it as Gospel. The Sn 5307 was more noted for the change in the 2U,s transmission from the “Selective gear” transmission (Slide Bar) to the “Constant Mesh” type transmission.

I can’t find a parts manual that shows when the oil clutch in the D8 2U did arrive on the scene, but, I do have other information showing in fact it was Sn 21513 (I knew that but forgot). Not only is Sn 21513 the right number when they became standard equipment, it is interesting to note (to some at least) that the first oil clutches in the 2U’s had trouble being disengaged and had to be repaired in the field, but that problem was corrected effective with tractor number 2u21693.

Old Magnet
12-03-2006, 06:22 PM
Hi Kelly,
Yes it is a bit confusing. The oil clutch shows up in the 2U1-2U9661 parts book but only as a field change over. The dry clutch was carried along up until Sr. # 21,512. Interesting that the oil clutch is offered only as a field change over and not as an attachment option. Makes it look like you could only get a dry clutch from Cat and would have to have the dealer change to oil unit if requested. What's your take? I know we went through this before:D :D will have to take better notes this time.

12-04-2006, 12:03 AM

It is strange, Cat having the change over groups in the parts manual 2U1-2U9661. You might be right…..are you saying maybe Cat was issuing the oil clutch as a add-on change over group before is was standard equipment in the 2U‘s ?

What do you think of this “Shade Tree Assumption”, that the parts manuals in question were printed at a later date and the oil clutch change over groups were an addition to the publication? Sn 2U9661 was a 1950 tractor some three (3) years before the oil clutch was introduced with tractor Sn 2U5613 which would be a 1953. Am leaning to the S.T.A..

I have the same parts manual 2U1-2U9661 with the same change over groups as yours and 2U-2U15000 which has the oil clutch charge over groups as well. The 2U15000 would be a 1953. But I don’t have a parts manual showing an thing about tractor 2U-21513, service manual yes, parts manuals no.

Yes, better kept notes for sure. I think about everything on this BB have being gone over at least once. ;) LOL


12-04-2006, 05:15 AM
Kelly & O.M. - The release information on the oil clutch for the 2U series D8 is found in the Service Magazine dated June 30, 1953.

There's over 10 pages detailing the construction and operation of the new clutch .. and also the major changes .. not only from dry clutch to wet clutch .. but the additional changes of ..

1. Improved crankcase guard ..

2. New type steering clutches with greater capacity ..

3. New type steering clutch control group, with easier steering control ..

4. Changes to the design of the operating linkages for the #24 CCU, and the #46 Hyd control (due to the oil clutch design) ..

5. A range of transmission improvements (bronze bushes in the gears .. replaceable races for the idler gear .. double row taper roller bearings at the forward end of the pinion and upper shafts) ..

6. Changes in the reverse speeds of the standard transmission ..

7. The option of a special 2H 1530 Transmission Group .. which has 6 mph speeds in both forward and reverse gears ..

8. An alteration to the transmission shift pattern ..

9. Design changes to the instrument panel (the oil pressure gauge and temperature gauge were relocated to the center of the dash to improve visibility .. and knock-out holes were provided for ammeter, dash light, and switch that were included with the optional lighting system groups) ..

10. Design changes to the floor plates, to allow for the fitting of a semi-recessed battery box ..

The Service Magazine states that the oil clutch was available as a retro-fit to 2U 5307 and up .. and gives 3 separate changeover groups, for retro-fit of the oil clutch to ..

1. Tractors 2U 5307 to 2U 14278 ..
2. Tractors 2U 14279 to 2U 16899 ..
3. Tractors 2U 16900 and up ..

These changeover groups were comprised of a number of components that were specific to the tractor S/N range that they were intended to fit ..

The fact that parts catalogs show the oil clutch as a fitment to tractors from 2U 5307, can be easily explained, as Kelly suspected .. that the parts catalogs are later reprints, and include the clutch changeover parts, as part of Caterpillars regular upgrades of written info ..

Kelly - I trust this info jogs your memory back to your operating days, when those improvements appeared .. and I know, you'll probably be able to add to what I've itemised, from your personal experiences .. :D

Old Magnet
12-04-2006, 08:38 AM
Hi Ozdozer,
Thanks for the info, the 1953 Service Magazine explains when the changes occurred and the parts manual reprint explains the sequence. I don't think this topic would ever be resolved without the advantage of the BB's.

12-04-2006, 01:00 PM
Thanks for typing all that up. What I first remember about the oil clutch on those old 2U’s was you never had to have a gallon “Log Cabin Syrup Can” full of engine oil riding on the deck for the clutch fingers, that leaked allover your slicker sack. With those old dry clutch’s, you could take off the small cover on the deck above the clutch and pour a small stream of oil at low idle on the upper right bolt hole and it would hit right on the clutch fingers……easy to engage after that……almost as easy as the new oil clutch it‘s self. Thanks again. Om and myself swear to keep better notes, since this subject has been gone over before. LOL