Help! Cat D4D SN:84J798 Information and Advice

[WesMohler]

I am new to equipment restoration and need help identifying my Cat D4D. (See Pics Below)

Original SN: 84J798

At some point, a previous owner stamped a "Z" over the "J" but I am not sure what this means. Need help please.

Current SN: 84Z798

A few things I think I know...

• This cat does not have a "hard-nose" so I think it would be an Ag tractor? However, I do have a utility blade where the arms can swing back and attach a ripper bar.
• The "Z" stamped over may have something to do with the transmission?? Rebuild?
• Engine runs well, clutch seems to stick engaged sometimes.
• Track "tensioner" grease seals were replaced

My Dad and I want to be able to run the dozer blade, or take it off and run a BG low-pressure open bowel scraper. Really hoping to get some info, advice, and history on this machine. Looking to restore it over the next few years and post update videos on Youtube. Any help is appreciated, thank you.

 

[Old Magnet]

The 85Jxxxx series is a " Special Application" Ag tractor, Direct Drive with sliding gear transmission. D330A engine.
My info is conflicting with one source saying 1969 and another 1972 production. Maybe someone else can pin it down closer.
There has been discussion about other "Z" marked units. As I recall the only conclusion was the the "Z" designation was For "Zigler Tractor" a major US equipment and service company.

 

[Coaldust]

We have a great ag track - type tractor discussion going on, that Truck Shop started.

That old girl looks like a gem. I would totally restore that beast (with your money).

 

[WesMohler]

We have a great ag track - type tractor discussion going on, that Truck Shop started.

That old girl looks like a gem. I would totally restore that beast (with your money).

Can you share the link to this discussion?? I can't seem to find it.

 

[.RC.]

The 85Jxxxx series is a " Special Application" Ag tractor, Direct Drive with sliding gear transmission. D330A engine.
My info is conflicting with one source saying 1969 and another 1972 production. Maybe someone else can pin it down closer.
There has been discussion about other "Z" marked units. As I recall the only conclusion was the the "Z" designation was For "Zigler Tractor" a major US equipment and service company.

It has a D330C engine by the photo's. Which would correspond to either a 69 or 72 DOM.

 

[Old Magnet]

My apologies, D330c is correct. My quick glance at the parts book locked onto the fan drive thinking it was a belt drive pump.

 

[Coaldust]

https://www.heavyequipmentforums.com/threads/crawlers-i-photod-recently.94225/

 

[OzDozer]

OM actually got something wrong re an antique Cat? Record this rare event!

The "Z" stamping over the "J" is odd, seems like it might have been an attempt by thieves to hide the real Serial Number?

My book says 1969 year of build. It's a very early production number, Cat produced over 4000 84J machines between 1968 and 1977.

Because the tractor is not fitted with a hardnose, you will not be able to fit the standard construction-style blade - but you can fit a "toolbar" blade, which has the swing-around sidearms for fitting either a blade or toolbar.

 

[FWD]

My book says 1969 too.
FWD

 

[Lumberjack Matt]

Parts are still easily available, do it!

 

[Nige]

Normally any Part Number with a "Z" in it indicates some sort of Custom Shop Arrangement or Custom Shop attachment.
However I can find no trace of a 2Z-3634 Arrangement or Group anywhere.
Why a "Z" would be stamped over the top of the "J" in the machine Serial Number I have no idea.
There isn't a plate somewhere on the tractor with "Custom Product by Caterpillar" (the image below may or may not look like it) by any chance does it.?

 

[WesMohler]

Parts are still easily available, do it!

Awesome, thanks for the advice Matt.
Ps: Huge fan of your YouTube channel. Looking forwards to the next few videos, especially since your build turned out so great.

 

[WesMohler]

Normally any Part Number with a "Z" in it indicates some sort of Custom Shop Arrangement or Custom Shop attachment.
However I can find no trace of a 2Z-3634 Arrangement or Group anywhere.
Why a "Z" would be stamped over the top of the "J" in the machine Serial Number I have no idea.
There isn't a plate somewhere on the tractor with "Custom Product by Caterpillar" (the image below may or may not look like it) by any chance does it.?

View attachment 273712

Unfortunately no, There is no plate or decal on the tractor resembling this.

 

[Nige]

Unfortunately no, There is no plate or decal on the tractor resembling this.

Shame, but it was worth a try. Generally anything with Z or Q in the Attachment, Group Number, or Part Number indicates a Custom Shop product. The unfortunate part is that way back when your machine was manufactured the Custom Shop did not have a good reputation for supplying parts and service information for their offerings. What was on microfiche was probably thrown into a dumpster decades ago and unfortunately very little of it made it to the present day online system. The only publications listed applicable to your Serial Number are a Maintenance Manual and a Parts Manual, both covering the 84J prefix from first machine built up to 84J1524.

Have you tried registering on the ACMOC site and asking there.? There is a lot of knowledge of that generation of machines on that site.

 

[Welder Dave]

Maybe a dealer modified tractor possibly by Zigler tractor?

 

[WesMohler]

It could be more obvious than I previously thought.

The tool bar /dozer attachment
that was on tractor when purchased from the water utility district is all cat yellow and seems to be a Cat/ or cat accepted “aftermarket product” . Blade and arms seem “normal” but it’s support is overbuilt and larger than all others I’ve seen.

The dozer steel support area that bolts up to both outside undercarriage sides is extremely heavy duty and 2” thick rather than the typical approx 1”thick I’ve seen all all other D4’s with tool bar/dozer attachments.
It’s so thick and 3” in excess height that it physically
didn’t allow the main track guards to unbolt and slide off to outside.
They were piled up with dirt for long time and not accessible to service track assembly.
Torched them off / found new ones and modifying slightly the
oversized toolbar support area
to achieve access.

Possibly the oversized toolbar support assembly is the “z”??

No one known in sales transaction of tractor from
Cat dealer to ag business to water district to talk to - I’m left with some “guessing” .

Thanks all for help.