Cat 977 undercarriage

I was wondering if a 977L has the same undercarriage as a 977k and also are the engines interchangeable?

no the 977L has the 8.5"pitch track and the older 977K series has the 8".. 18"w track pads should be interchangeable tho..the early 977K had the D330 and the 977L had the 3306. Cat changed to the 3306 in the 977Ks somewhere in the later serial # range; maybe Nige can chime in on that. If you swop the whole engine/torqueconv into another loader it should work as the only connection to the transm/bevel gear case is the prop shaft under the op station

The early L's up to about 1973 kept the 8" pitch, up to about 11K5959.

StumpSlinger said:

I was wondering if a 977L has the same undercarriage as a 977k and also are the engines interchangeable?

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Impossible to attempt to answer without knowing the Serial Numbers of the K and the L in question, and even then an answer is not guaranteed 100%.

To give you some idea below are a few snippets of info.

The 977K was first introduced in 1967 (US), and 1968 (Japan & Scotland). It had a turbocharged D333 engine producing 170 FWHP. The 977K was manufactured in the US, with an 11K or 46H Serial Number prefix, in Japan (70J or 76H prefix), and in Scotland (48J prefix).
In 1971 Caterpillar replaced the 977K with the 977L but retained the same 11K/48J/70J Serial Number prefixes that were previously used on the 977K models. (977K 46H prefix (US) and 76H prefix (Japan) production had already ceased before the 977L was introduced onto the market.)
The 977L featured an increase in power to 190 FWHP, beginning with Serial Numbers 11K3919, 48J586, & 70J1303.

So the early-production 977L tractors were in essence nothing more than uprated K models using the same engine but with a tad more horsepower.

AFAIK it was only when the "new version" 977L of 14X Serial Number prefix (US-1978), 64X (Scotland-1979), and 95X (Japan-1980) came on the market that the power unit changed to a 3306.

^^^^and there you have it.

Truck Shop said:

^^^^and there you have it.

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Oh no you don't..............
That's just a taster, maybe only about 10% of "it" where 977K/L models are concerned.

Too many options spoil the cat!

Thanks I don't have s/n now. How do I tell the track pitch?

Try to find a place where the track is reasonably tight and with at least 5 track pins in a straight line. If you can start the machine and put it in reverse then gently ease back until the top run of the track is not sagging so much the better.

Measure the distance between the centres of Pins #1 & 5, then divide the result by 4. That’s the track pitch.

Nige said:

AFAIK it was only when the "new version" 977L of 14X Serial Number prefix (US-1978), 64X (Scotland-1979), and 95X (Japan-1980) came on the market that the power unit changed to a 3306.

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I'm pretty sure that there were some 11K's with 3306's. I bought a 977L 11K that originally came with a 3306. The previous owner had put a D333 in it. He has had a number of 977's over the years and knows them pretty well.
I no longer have that machine and can't for the life of me remember the serial number. I still do have the service manual for the machine and the engine section is for a 3306. I don't know anything about the 64X and 95X machines.

Bam, you may well be right. The problem is that the information available on the 977K/L is confused at best.
TBH my first call is always to look at the engine to see whether or not it carries the same Serial Number prefix as the tractor. If the engine is the exact same S/N as the tractor that would indicate the engine was the original D333. An engine of the same S/N prefix (e.g. 11Kxxxx) as the tractor but a different S/N would still indicate a D333 engine but not the one originally installed when the tractor was built.
On the other hand a 3N or 49V engine Serial Number prefix would indicate the tractor had a 3306 engine installed.

I agree 100%. I have no fact's as to exact serial number breaks etc. I am only going off what I have been told by a couple of contractors who have owned numerous 977's over the years. Those machines were pretty popular in my neck of the woods 15-20 yrs ago for building terraces. Nowadays most of the 'loader guys' are running 963's and 973's.

The "K" model became "L" model @ 11K3919 and both used the D333c until the 3306 (3N) came in at 11K5051
8.0" track pitch to 11K5958 then changed to 8.5"

Thanks again, there's several 977s grazing around my community that could be bought and I would like have one with a parts machine. Looks like I have some homework to do.

Just for starters the 8" pitch ran on all the 977K's and then on L's till the 11K5958. The undercarriage is hard & expensive work. If it works for you I would go with the newer 8 1/2" machines.

Cat977 said:

Just for starters the 8" pitch ran on all the 977K's and then on L's till the 11K5958. The undercarriage is hard & expensive work. If it works for you I would go with the newer 8 1/2" machines.

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Hi there
Question... With the track pitch being different.. are the pads different from a 11K to a 14K machine?

Vaughn86 said:

Question... With the track pitch being different.. are the pads different from a 11K to a 14K machine?

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Yes. The pads are different.

Nige said:

Yes. The pads are different.

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thank you