Ricky Beals

How would I go about figuring out which one?

I noticed today that my oil pressure in mack rd688 never gets over 30 psi. It usually runs around 20 psi and I’m thinking that’s awful low. It is full of oil, runs fine so maybe my gauge is faulty. What do you guys think?

I have a 2000 RD688 and the air gauge in the truck has two needle, green and orange. When I really trying to stop my truck the green needle drops pretty quick. I have to watch or the parking brake light comes on. I can hear any air leaks but I’m thinking I have one. Can someone with a little more experience explain what’s going on and how to fix it. Thanks in advance.

Can anyone tell me the correct bug screen to get that will fit my 2000 mack RD688. When I purchased truck it didn’t have one. It fits in front of radiator and I think uses screws to attach it. A mack part number or a aftermarket part number would be fine. also if an add says it fits R600 does that mean it will fit my RD688?

Sorry guys I have been busy with a dozer that I had to have and believe me I wish I had never bought the damn thing. I got a lot of irons in the fire. Transmission is a Eaton fuller 8ll. The shop called me yesterday to tell me truck is ready. I never have gotten the truck since I dropped it off 1.5 months ago. I would stop in and one of the mechanics left in the shop late in the day would tell me what He had heard was wrong. My invoice said the slave cylinder was rebuilt. Nothing was wrong with truck except the clutch was going out. I took the truck in and clutch was replaced but when they test drove it the hi-low switch wouldn’t work. So they went to replacing parts but the first two parts didn’t fix the problem so they put my old parts back on. Today I went by to pay my bill which was 3300.00 and again owner wasn’t there but young mechanic said the slave cylinder was rebuilt. Which fixed my problem. Sorry that’s all I know and will have someone take me up after work tomorrow to get the truck and drive it back home. Thanks for all the advice and I may be asking for more but hopefully this truck is ready to work.

I’m guessing I need to make a decision on this whole mess. Go get my truck and take it to the mack dealership. Surely to the heavens they have tripled checked those air lines.

Macks it turned out good. We ended up having to the trunion bar due to a loose nut wearing away all the threads. my biggest concern on this whole hi/lo switch not working. I was told the valve on the transmission was worn out they replaced it and problem still there. They have replaced two parts and not fixed the problem. Yes they put my old parts back on but the trust isn’t there. I mean if the first valve they changed out was worn out how is it working now. im no mechanic but my gut tells me they have screwed something up and they don’t even know what it is they have screwed up.

Still don’t have my truck back. The shop has replaced two parts but not finding the problem. They have put my old parts back on. They are now saying they have to rebuild a valve located near the rear of transmission. My question is this a coincidence or did someone mess something up replacing my clutch? Again my high/low switch was not working. Before clutch replaced never had any issues with it.

They were saying at the shifter but last I talked to them they said it was a valve on transmission that operates hi/lo

I had a local shop to replace my Eaton fuller clutch. Never had a problem with hi/lo switch leaking air or not working. Well after several weeks I went in to check on truck and was told The hi/lo switch was leaking air. Nobody really could tell me what exactly was wrong seems they were wanting me to talk with main mechanic. Next day I talked to main mechanic and said the lines were correct( thought they were switched) and he would have to trouble shoot. Week later he is saying a valve on top or side of transmission is bad. Does this make any sense to you guys. I’m at the mercy of having to listen. Is this a coincidence that the valve went out. Never had a problem out of hi/lo switch before?

I have a Kolbelco 135 what is yours. How long is your trailer on the flat part?

Ok thanks guys for the input. I’m going take it off.

Here is a photo of the trailer plug on my dump truck. Can someone tell me what this does? I always thought it was a 7way pin but it only has this one big wire going to it. Thanks for any help on this.

looks like I’m going to get a new clutch. Took it by shop and they tried adjusting it but couldn’t. This is a Eaton fuller 8LL. They mechanic said it would cost about 3,000 for parts and labor. That sound about right? I also have noticed a loud rattle/vibration in the higher gears. It quits when I let up on gas. It doesn’t do it all the time but it’s starting to annoy me. What do you guys recommend I do to try and figure out what’s causing this. My driveline right out of the transmission is not timed correctly. It’s a little off so could that be causing it?

I have the Mack truck in subject line. It only has a tractor brake inside cab. I purchased a 30,000 lb dozer and I was wondering if I could add trailer air brakes and tow this dozer. Would need a tag trailer rated for 40,000 lbs. Before I even waste time thinking about it was going ask some of you more knowledgeable guys if this was even a possibility.

Macks I didn’t see this until this evening. They came and went. It was just one guy. He took a grinder and cut a slit below the Trunnion bar in the stand. He then drove a couple of small chisels into those cuts. He then cut the bar right behind the stand on both sides. Took a 20lb sledge and knocked out both side. He then took the new Trunnion bar and slicked it up and we put it in one side of stand and drove it thru the other side. He welded everything up and was gone. Took him 2 hours.

I did inspect the bushings and they were not worn all the way thru. I’m like you guys this isn’t the original Trunnion stand. The bar looked really good just those threads were gone on one end. Yes everything is new on rear suspension and I’m talking everything. Replacing brakes while I’m back there. These guys are out of Little Rock which is central Arkansas and I’m down in SW Arkansas about 130 miles from them. They quoted 1800.00

Honestly this hasn’t been that hard of a job since we took the bed off. We talked about putting a new Trunnion stand in from Mack. I’m thinking the price was around 3500.00 and a lot more cutting and pulling the rear tandems out. The biggest factor is waiting on it to arrive and we are looking at another week. I have decided to go with axel surgeons and wrap this up this week. Bottom insulators were trashed. Anyway wanted to post up and let you guys know I didn’t fall off the face of the earth.

The bar is smooth just a lot to f grease on it. We pulled the bed and had the cylinder repacked. Changed out hydraulic fluid in the tank. Getting the old girl ready to start hauling.

Well gang just not w getting to the suspension. Pulled it all off and Trunnion bar looked good until we got to the passenger side. There are hardly any threads left. The whole bushing just slid off the bar. The bar was in really good shape, no cracks in welds but I don’t see anyway around not replacing the bar. Not going tack weld the nut on it. Probably call Axle Surgeons in morning.

Ok will call you tomorrow

You still have the glove box? If so will it fit a 2000 RD

I guess I can get a quote from Mack dealer and Stengelbrothers on spring kits My best friend hurt his back 35 years ago torquing those u bolts on a camelback. He worked part time for a diesel repair shop after school and weekends. He was using a multiplier and long cheater bar. Sitting flat on his ass and rowing like he was in a boat. Crazy but I just remembered that story.

I’m thinking that when you guys say do it right your talking springs, and the whole bit. Which makes the video Onyx610 posted (which I watched) spot on. If doing it right means replacing the springs might as well get the kit in the video where it’s already done. Just installing the springs and insulators.

The truck is my personal truck. I worked as an Insurance agent for 27 years and built a nice business. The company I worked for figured out a way to get out of their contract and well they did. I have known for a few years that I was very unhappy with the life I had. When the job ended and it just ended I asked my wife of 30 years if she would move back home where I grew up. I have always wanted a dump truck, excavator and bull dozer. A lot of folks including my wife say I’m a little crazy, might just be. I got the excavator and dump truck and hauled 30 loads of gravel for a house and shop pad. Not one time did I ever think I was working. At first I didn’t like digging near the edge with excavator but I got some seat time and now it doesn’t bother me at all. I bought the wrong dump truck and made my first post on here about changing out the front springs. It was a mack tractor that was converted to a dump. I then sold that dump and bought the RD688 and I think it’s a good truck. To me this is fun and I definitely understand my limitations. Would never try and rebuild the motor, tranny or rearend. This I think I can do with my buddies help. If the Trunnion bar and saddles are good than it was a good call. If not then I will probably post up here and see what my options are. Macks what is rebuilt back right? I have looked the springs over and not one is broke. Do they need replaced? If not then I’m going to assume everything from saddle back to cover gets replaced. On Insulators ATRO makes a kit that has all the bolts and pads. Should be good there. I’m paying the guy helping me but he is also a friend. He will be out of pocket for a few weeks but we should get this down last week in March. Mark T that’s what makes me a little hesitant. It’s a gamble and I know it. The money ain’t a problem because I have already set it aside. I’m OCD and know I will do it right. If we end up with a bad bar or saddle’s then we are over our head. I will be calling Axle surgeons of Arkansas. Think I’m going try it. It may even be fun and I definitely learn a few things.