D4 2T 5T Compatibility

One is Wide guage and other is Narrow , so I think every thing except wide componetry should Fit . there were Changes during these in location of carrier rollers I know, but basics are the same, most of these parts are common to the Gas R4 also . LJ

Hi, Hookblock and Lance Jones.
It is my understanding that the 5T was the next model on from the 2T, not the wide version of the 2T. As far as I know, both came in narrow or wide versions with some of the wide machines having a 'W' after the serial number. The 5T was, I believe, the first with the bigger outer track frame bearings, outboard of the sprocket. Other than that, there is not a lot of outward difference in appearance between the two.

Personally, if the track frames and outer bearings are in good shape on the 5T, they are the ones that I would be using, athoughI think it may also involve using the 5T axles, sprockest, etc.. I think there is a pretty high degree of compatibility between the two models and I suspect that there was a slight increase in horsepower in the 5T.

If there an 'SP' suffix after either serial number, that machine would have some special parts in it. These were quite often in the transmission but could also cover things like lighting, electric starting on either the pony or the main and other items.

Hookblock, how much is wrong or missing on the 5T machine?

Hope this helps.

The 2T & 5T are basically the same tractor.....comes in narrow or wide gauge....the change to the large rear hubs occurred at 2T8270. The corresponding track trucks match the small or large hubs.

Thanks for the info guys. What I have is a D4 2T779 and the D4's I found are 5T9565W engine # 7U2083 The second is 5T2093 engine# 5T2023 The third is 7J5562WSP They are in rough shape motors are tight and parts missing. I am down to the second one as an option. One reason for the parts machine is where the draw bar bolts to the tranny housing 3 of the 4 bolts broke the casting, and if it can be fixed I wouldn't have to swap it out. The second reason is the second machine has a blade I might be able to use on my machine.

Hi, Hookblock.
That's a bit of a menagerie that you are looking at there. The 7J series is the first after what was originally the RD4 with a name change to just plain D4 during its production run. Then came the 2T and the 5T, both of which came in narrow and wide versions. These were followed by the 6U - narrow - and 7U - wide - models.

T'would appear that the first 5T hes been re-engined with a later motor out of a 7U series crawler. Nothing wrong with that, just a bit more grunt.

If your country is at all hilly, that first machine, the wide 5T - 5T9565W, would be a good one to build on, especially if you have enough good undercarriage parts. As I understand it, the track frames and outer bearing are specific to the models/machines they came from. Track frames from machines with the larger outer bearings will not swap to the smaller outer bearings and vice versa. I am not sure if there is any difference in the axles and sprocket hubs but would not be surprised if there was some difference.

Pity it doesn't have the dozer on it.

As far as I am aware, the rest of the machine is pretty much the same for both 2T and 5T models.

I am curious to know how come those 3 drawbar mounting bolts broke the casting out 'cos they are only supposed to be carrying the weight of the drawbar and any supported implement, NOT doing any actual pulling.

Just my 0.02.

Hi Deas, Thanks for the info and help. It was used in a factory as a winch tractor with a draw bar added out the front to tie the tractor off, then the line off the winch run through snatch blocks to what ever they were moving or picking. It was my first cat it ran good everything else worked good the u/c was in good shape, seemed like a good little project and still does, after all if it was easy whats the challenge 😉 I was excited about it and missed a few things.

That's to bad....drawbar out the front probably put wrong leverage on the bolt pad.
Judging from the oil, I'd suspect the housing is cracked also. It's a big job but I think the only way it would be right again is to swap out the case......or transfer the good parts to another tractor which you are apparently considering.