Cat 977 Mayday (Blueox/Nige-help please!)

[Robert Boggs]

I took a few vacation days to get some things done and had an incident on the Cat 977L or K (11K 01133 according to the engine). A friend was running it and yelled on the radio it lost drive. I can hear the machine load lightly when I run it through the gears in forward and reverse, but it won’t budge. First dip of the trans stick was dirty, but the next two were spot on and clean. I’m thinking something broke in the link between the transmission and steering clutch(s). What connects the two?. Any other thoughts?

Best

 

[Nige]

Start by lifting the floor plate and look at the drive shaft between the torque converter and the transmission. With the engine idling in neutral the shaft should be rotating. Engage any gear and it should stop. Shift from one gear to another and the shaft should turn slightly then stop again. Try that in all gears and report back.

 

[Robert Boggs]

Start by lifting the floor plate and look at the drive shaft between the torque converter and the transmission. With the engine idling in neutral the shaft should be rotating. Engage any gear and it should stop. Shift from one gear to another and the shaft should turn slightly then stop again. Try that in all gears and report back.

Thanks Nige, that's the first thing I checked but incorrectly assumed it should remain rotating. It does NOT stop rotating, and even appeared to speed up as I moved through the gears.

 

[Robert Boggs]

I need to bite the bullet and buy a repair manual for this machine. If anyone could tell me whether this would be a 977K (I think) or an 977L repair manual, or share a service manual part number that would be great? Serial number (only found on the engine): 11k 01133

 

[Nige]

Thanks Nige, that's the first thing I checked but incorrectly assumed it should remain rotating. It does NOT stop rotating, and even appeared to speed up as I moved through the gears.

That means that the transmission clutches are not engaging, usually but not necessarily as a result of low transmission oil pressure.

With the floorplate up take a look for the housing containing the magnetic screen. It will have a cover secured by 4 bolts. Get that screen out and post photos of what you find stuck to the magnets (metallic) and to the inside of the screen (non metallic).

Do you have pressure gauges capable of measuring up to say 400psi.?

 

[Nige]

I need to bite the bullet and buy a repair manual for this machine. If anyone could tell me whether this would be a 977K (I think) or an 977L repair manual, or share a service manual part number that would be great? Serial number (only found on the engine): 11k 01133

The appropriate Service Manual for 11K01133 is Caterpillar Publication REG00635. See this LINK for one on eBay. There are others if you search under the Publication Number. A new one is priced at $285 BTW, so don't go paying too much.

 

[Robert Boggs]

I'll check it out soon as I have a chance.

If I don't have a gauge I can get ahold of one this evening. Does the machine already have provisions to pressure test, or will I need a tee? If so, would you happen to know what thread type/size? Thanks!

 

[skyking1]

@Robert Boggs are you in Washington? I worked with a Boggs a few years back.

 

[Robert Boggs]

@Robert Boggs are you in Washington? I worked with a Boggs a few years back.

No sir, WV.

 

[Nige]

Does the machine already have provisions to pressure test, or will I need a tee? If so, would you happen to know what thread type/size?

A machine from that era is not likely to have quick connectors for testing, probably threaded plugs that will most likely be 1/4" either NPT or similar. You'lkl have to whip some of the p;lugs out and take a look. See the attachment. Don't go too far on this just yet, first get into the screen/magnetic filter and see what you find.

 

[tctractors]

You would find it best to use a 0 - 600 psi test gauge on all CAT powershift transmissions.

 

[Robert Boggs]

Very good call Nige on not getting too far trying to prep for fittings, I have trouble in paradise. I’m going to scour the parts manuals to see what I can ID, but assuming I’m into a transmission and full flush if I repair it.

 

[Robert Boggs]

Photo #5

 

[AllDodge]

Does look like the trans is coming out

 

[Nige]

Does look like the trans is coming out

Yep. She fcuked.

 

[Nige]

I’m going to scour the parts manuals to see what I can ID, but assuming I’m into a transmission and full flush if I repair it.

You’re also looking at a pump and a transmission cooler in addition to the transmission rebuild if you do it right.

 

[Robert Boggs]

I’m having a hay of a time even trying to locate parts new or used to pull an estimate together. Guessing I’m in the $10k-$15k range? Any suggestions on what would be the safest way to start it so I can get the bucket raised and tow it out of the way without further contamination?

 

[Robert Boggs]

You’re also looking at a pump and a transmission cooler in addition to the transmission rebuild if you do it right.

Sure appreciate you holding my hand through another one Nige!

 

[Nige]

I’m having a hay of a time even trying to locate parts new or used

Until you get it torn down I think it's highly unlikely that you will be able to make a definitive parts list. I worry about the metal parts that look as though they came from a bearing cage and what other damage that might have done.
Offroad Equipment in Alcoa TN is a good source from what others have posted on this forum. www.offroadeq.com/

 

[AllDodge]

Any suggestions on what would be the safest way to start it so I can get the bucket raised and tow it out of the way without further contamination?

Your not going to make it any worst, put screen back in and fire it up and lift the bucket.