Hello everyone I have a D8H 62A powershift Caterpillar bulldozer with some issues I couldnt trouble shoot in time for the season but id like to ask for some advice on what may be wrong. The issues are, it will not stay in gear pops out under throttle and under load will not pop into gear without a little bit of throttle seems to have grinding gears sound and feedback when shifting into reverse uphill sometimes loss of forward power once it warms up slowly lose steering once it warms up the clutch levers don't really give any feedback I took apart the clutch valve assembly and that seems to be clean and working fine I replaced the transmission pump because the book said that might be an issue When I got the dozer it barley had any steering, I ended up replacing the left clutch pack and brake band because it had signs of heat stress and fractures on the surface of the clutch pack I figured somebody had drove the dozer with heavy brakes on and ended up destroying that left side, I'm worried about any seals in the bevel gear clutch housing area it might've gotten really hot and melted the seals I think the clutch release piston may be damaged but the book doesn't have much information on that it doesn't even show how to take that out or disassemble it specifically, so I was hoping anybody could give me an idea about that as well. once I reassembled dozer with the new clutch pack break band and the new transmission oil pump I was able to turn right with a lot of brake pressure but I wasn't able to turn left very much still, then I took apart the clutch valve assembly and replaced transmission pump and I was able to turn left and right with a lot of pressure on the brake pedals. I adjusted the brake calipers both sides and I didn't help after the dozer warms up and I run it for 20 minutes I start to lose all ability to turn the dozer just seems to want to go straight If I do apply enough break to get it to start turning the dozer it stop. then after I ran it 5 or 6 times after 30-40 minutes I started losing forward power and then all power, then after I let it sit for nine hours and cooldown it had power again and I was able to drive back and I ended up parking it for the winter book says it could be pressure modulation relief valve, load piston/differential valve spool improperly adjusted or stuck open, priority valve stuck open, leakage within transmission air or leaks in line oil or pump failure, and torque converter failure the bevel gears been replaced I replaced the transmission oil pump and checked for leaks transmission doesn't seem to be leaking although I do have a leak into a final that seems to be filling up constantly, I believe it's coming out of the bevel gear/clutch housing I'm not sure. someone prior to me definitely got into the transmission housing underneath the seat and I'm not sure what they did if they adjusted anything im a bit nervous to get into the transmission, not sure if I need to check into that yet I was hoping it was something simpler
Do you mean 68Axxxx? never heard of a 62A. Do you have a service manual? Need to run pressure checks, on both transmission and steering clutches. That should tell what's going on. Kind of seems like steering clutch piston seals are gone.
There are two serial prefixes that apply to the 8H as far as I know; 36A which was the direct drive model (4 serial breaks and not as common) and 46A (power-shift, 4 serial breaks). It would definitely help to have the last 4 or 5 digits of the SN to aid in troubleshooting. Another possible issue I see from my end is that SIS only lists the Parts Identification section of the Service Manual, there is little to no information regarding systems operation, troubleshooting, schematics, etc. Someone else out there with access to SIS maybe be able to confirm this? From what I can see the 8H was made from 1958-1974, with over 30000 power-shift units. You mentioned a book, is this the service manual sold with the tractor?
The 68Axxxx is the U.K. version of the USA 46Axxxx.
Possibly the 62A is the UK version of the 36A? Op mentions grinding gears, etc. Leading me to think it's a DD machine.
There is a 5 2A series, U.K. built. Very early production, 1960 -1962, with only 84 built according to ironrecord. I'd never heard of a 52A either.
52A =US 35A=fuel torque converter drive with constant mesh gear transmission and it's own special clutch. 776 units built, I have the parts manual. 22A is U.K. version of US 35A Direct Drive/oil clutch
62A is a 561B sideboom tractor. Or a V60E, 70, 80 or 90 lift truck. Bob
22A is closer to a 36A but not the same. Bob
Shows 62A to have a D333 engine and Direct Drive????? Yes, 22A is U.K. version of US 36A Direct Drive/ oil clutch (my typo)
Thank you for helping me with this. sorry to say the dozers way out in the bush at the Brooks range. It has a square tube reinforced rollover cage, hydraulic tank on the right side of the seat, 4 barrel ripper. I left my note page with the serial numbers at the mine, big mistake. The books I have at the mine were collected by the previous owner who broke and replaced the bevel gear. Ill be bringing out sets of gauges to test with for sure. This is the hydraulic tank serial numbers and a few other pictures I have if that helps ID it.
Since the hyd. control is a 193B 3 valve US built I'm gona guess 46A. Bob
Agreed but my parts book shows that s/n to be for the 183 & 193 Hydraulic Control. No "B".
Your tractor looks either a UK built 68A or US built 46A D8H. Either way,you may be in for a hard run judging from what I've read of your comments. You'll need an experienced hand,some specialist pulling gear,and a few coins in your bank. Getting the right man for the job with experience may save you thousands. Start with getting a good fitter.
so to summerize: dozer wont stay in gear (pops out under throttle, sometimes under load) Wont go into gear without some throttle losses pushing power over 45 minutes or so loud grinding sound a couple times when backing up-hill gradual loss of forward power (takes about 45 minutes) as well as reverse takes a hell of a lot of break and throttle to turn, and feels like the clutch levers dont do anything so it losses steering power as well as forward and reverse as it warms up. Also has anyone seen crush type hydraulic line o-rings? NC CAT here in Alaska doesn't have any idea what I showed them. The o-rings have a rubber core wrapped in thin aluminum or something like that. they crush to seal. I need know some type or terminology or name for them so I can try to hunt them down.
It all sounds pressure related to me. Which would do all the symptoms you say. Also, what does the trans screen, filter and magnet look like? Nige hopefully will chime in.
It was full of bearing and parts from the bevel gear bearing and seals, I cleaned out and replaced. the previous owner said he had replaced the bevel gear and it did drive 60 miles up and over a mountain range to get here. I did replace the transmission pump, but I haven't had a set of gages to check it with. I figure the break got left on and the clutches heated up until the bevel gear could sbearing Iand seals whent, then the heat ruined the clutch packs, I could see stress fractures on the surface, lots of heat damage to the clutch area. Could it be something in the tourque converter?
60 miles! Holy crap! I'd love to get up there sometime to experience that terrain.
The best thing that could be done with an D8 of that vintage after being tracked 60 miles (probably with no precautions being taken to monitor final drive temps, oils, etc) would be to turn it into a boat anchor. It's probably all it'll be good for. When you go into the back end make sure you have a decent-size shovel ready. You'll need it to dig the all the metallic debris out. I hope you have a large bank account. You're going to need it. Best of luck.
Just the time it does run it it makes me enough money to not retire it yet, but I have a few newer ones running full time with other equipment. I cleaned out the clutch and finals, and changed all the fluids. It's has a new bevel and new clutch packs, new transmission pump. I believe it's a pressure issue for the transmission, I'll test it with gages, and then the clutche position seals may have melted from when it got ran with the break on, and as it warms up they do not disengage the clutch packs anymore. I'm headed back out there to start mining April 15th and I won't have any contact so I am trying to get any information that I can about this because the books don't have any more for me.
Temps were good pressure was good all the way out there it did sit for a few years before it was ran again and then these problems started.
No s/n, no pressure tests = no answers.
Pressure operates the steering too
I'm confused is this a direct drive or power shift. oil filling up final drive is pinion seal on final drive most likely loose pinion bearings. You say that it pops out of gear and grinds. that makes me think it is a direct drive if it is trans has to come out and be rebuilt. Steering could be your steering clutch seals did you replace them when you had the steering clutch out normally loose bevel gear bearings will knock out the seals
His pictures show it to have a Powershift selector tower
Thanks it pops out of dear because the neutral safety valve is detecting low pressure check pressures have you pulled the magnetic strainer and checked it yet
Over the course of several months, I worked on this bulldozer, only to uncover a significant issue: the transmission’s last gear pack had suffered irreparable damage. Consequently, first gear remained nonfunctional, and stearing wasnt availible I belive as a result, and the entire transmission teetered on the brink of failure. In the field, I executed a transmission replacement, adapting it to accommodate the older model of the replacement unit. The bulldozer has faithfully served for the past few years. Now, as part of its ongoing maintenance, it is receiving new rails, pads, and sprockets. Fortunately, most other components were virtually brand new when I acquired it. Reflecting on the journey, I’m relieved that I didn’t consign it to the fate of a mere boat anchor.
Here is a video of It's first real test after the new transmision was installed.
I am curious to know how driving it 60 miles would automatically destroy it.
So you don’t see a problem driving a 60 year-old dozer 60 miles “over a mountain range” (to quote the OP) with a failing/failed transmission coupled with a dodgy rear end.? And that is before one starts to take the subject of undercarriage into consideration. The good thing about tractors from that era is that everything is repairable provided that you have money, parts, and a man with tools who knows what he’s doing. Of the three the last factor is probably the most important. Whether the OP has someone like that available I have no idea.
No I do not have a problem with a machine of that vintage being driven 60 miles (your post mentions vintage, not condition), especially when back when that machine was new, long hauls between jobs would not be uncommon as cartage and roads were not what they are today. Even around here back in the 1990's a company roaded some 660 scrapers a hundred km to get to a new job. Back in the days pre internet I remember reading about an expedition in Antarctica and I am not sure what they were but were either D6H's or a D7H's and all they did was pull a sled train on the expedition. I am sure if someone stuck any machine in third gear and flat out for 60km things might not go well, but 3rd gear and 1\3 revs I always found a comfortable travel speed.