Re: How Much to Spend for Service on U300 Reply #25 – June 15, 2011, 10:24:15 am Kent,I would make sure that this person has the equipment that can read the engine codes. If he is good he should be able to explain what each code means. I would call FOT to find out the final drive (rear end) ratio. I would be very surprised if Foretravel put in a high numerical ratio. Please let us know what kind of luck you have with this guy so we can add him to our list if he is good. Quote Selected
Re: How Much to Spend for Service on U300 Reply #26 – June 15, 2011, 11:11:17 am If rear axle ratio is of interest, most axles have a small plate with the ratio on it along with the axle serial number.Brett Quote Selected
Re: How Much to Spend for Service on U300 Reply #27 – June 15, 2011, 11:52:26 am Quote from: wolfe10 – June 15, 2011, 11:11:17 amIf rear axle ratio is of interest, most axles have a small plate with the ratio on it along with the axle serial number.BrettBrett, I checked the plate. If I read it properly it is a RA 307 according to the plate. I have no reason to think either of the previous owners changed it. Quote Selected
Re: How Much to Spend for Service on U300 Reply #28 – June 15, 2011, 12:16:37 pm Wonder if that is 3.07?Remember with the 4 speed Allison, 4th gear is 1:1VERY different than 6th gear on a 6 speed Allison which is .65:1.Brett Quote Selected
Re: How Much to Spend for Service on U300 Reply #29 – June 15, 2011, 12:28:28 pm Quote from: wolfe10 – June 15, 2011, 12:16:37 pmWonder if that is 3.07?Remember with the 4 speed Allison, 4th gear is 1:1VERY different than 6th gear on a 6 speed Allison which is .65:1.BrettI sure hope its 3.07. Sorry, I always had problems with those little dots. That was kind of bad in business, particularly when marking up new products. I'm pretty sure 3.07 is the standard differential ratio for this coach and engine combo. Quote Selected
Re: How Much to Spend for Service on U300 Reply #30 – June 15, 2011, 01:06:41 pm Not surprising, 3.07 has been standard with the 4 speed and the 6V-92.Kent, under the valve covers, you only have the valve adjustments and two fuel lines per cylinder to check for leaking, IE, if leaking they will put fuel into the engine oil, NOT GOOD. Other wise, there is not much to the DDEC to check unless you want a scan on the computer or an update on the computer. For me, IF you are not making oil, meaning not getting fuel in the oil, and it runs nice, smooth, I would not be in a rush to have someone getting into the valve covers unless you have a heck of a lot of miles on it, like over 150K miles.FWIW and good luck Remember the ole saying "If it ain't broke, don't fix it" is still true Quote Selected
Re: How Much to Spend for Service on U300 Reply #31 – June 15, 2011, 02:21:28 pm Quote from: Dave M – June 15, 2011, 01:06:41 pmNot surprising, 3.07 has been standard with the 4 speed and the 6V-92.Kent, under the valve covers, you only have the valve adjustments and two fuel lines per cylinder to check for leaking, IE, if leaking they will put fuel into the engine oil, NOT GOOD. Other wise, there is not much to the DDEC to check unless you want a scan on the computer or an update on the computer. For me, IF you are not making oil, meaning not getting fuel in the oil, and it runs nice, smooth, I would not be in a rush to have someone getting into the valve covers unless you have a heck of a lot of miles on it, like over 150K miles.FWIW and good luck Remember the ole saying "If it ain't broke, don't fix it" is still trueThat's kinda where I am on things but this local mechanic already has the valve covers removed and we are preparing to check and adjust the valves as needed. He's going to replace a leaky starter gasket and change the oil while he's here but I am not going to change the antifreeze or transmission fluid until after I get them analyzed. I'm pretty sure the Allison has TranSyn in it based on the description given by the Allison guy I talked to. This stuff is a little browner than regular red transmission fluid and it smells different, not burned but different. I have verified the 6V92 is a dry sleeve engine and uses standard antifreeze and requires no additives. Thanks again to all who contributed. Boy I learned a lot from this thread. Thanks to all. Quote Selected
Re: How Much to Spend for Service on U300 Reply #32 – June 15, 2011, 03:46:48 pm Kent,Thanks for the thumbs up! In checking the book, you should have a 3.07 rear axle ration. You verified it by checking the tin tag attached to it. Brett had an excellent post with the formula for your speed vs. RPM. It worked out amost exactly with my speedo and gps readings.For others out there with 3.07 (or any ratio), here is a previous note to Kent:QuoteReading Brett's calculation memo about ratios and rpm, I got to thinking about the note you send me a while back. You said you were going 67 mph at 1900 rpm. I looked up the RPM (revolutions per mile) of our tire size. Plugging 512 tire rpm and a 3.07 rear axle ration into the formula, I came out with just a trace over 72.5 mph at 1900 engine rpm. This works out almost exactly to the real world numbers I got on my gps of 82 (calculation gives 81.5) mph at 2100 engine rpm. So, (engine rpm x 60) divided by 1571.84 (tire revolutions per mile (512) x rear end ratio (3.07) ) will give you the speed of our U300s at a given engine rpm in fourth gear assuming transmission lockup with 1 to 1 (direct) ratio. Hope this helps you figure out the reason for low fuel mileage and rpm/speed discrepancy on your next trip.The formula is: (Engine RPM x 60) / (Rear Axle Ratio x Tire Revolutions per Mile x Transmission Ratio) = MPH You can look up the the Tire Revolutions Per Mile by doing a Google search for the info for your tire size. If you have a six speed, just stick the .65 or what ever it is in your manual/online in the equation. Using the Foretravel manual to find the ratios, you can do a quick calculation of the speed/engine rpm for any gear in your transmission. If you know your engine RPM and speed, you can also work backwards to find your ratio.Has the new mechanic checked to make sure the trans is going into lockup? Kent, smart to do a trans analysis before changing. Don't know about the brown color. I have seen a dark brown/reddish color in transmissions with contamination or that got hot but they usually have a telltale smell. Perhaps other members may have encountered a brown colored trans fluid?If anyone suspects oil dilution, you can stick it and then walk into fresh air and smell the dip stick. If there is any diesel in the oil, you may be able to smell it (depending on your sense of smell). A good idea if you have a higher reading on the stick than you think you should. Quote Selected
Re: How Much to Spend for Service on U300 Reply #33 – June 15, 2011, 05:32:24 pm For anyone reading the last paragraph in my last post, the oil dilution and sniffing the dip stick I was speaking about was for engine oil not trans. It just got me thinking about an earlier post so I tossed it in. Quote Selected
Re: How Much to Spend for Service on U300 Reply #34 – June 15, 2011, 06:30:05 pm As always thanks again Pierce. I know what burned ATF smells like and this definitely does not smell burned, the analysis will tell the tale. I have used the local mechanic you found. He should be finished tomorrow with the top end. I also had a leak in the starter gasket which is needs to change. Other than that, everything looks pretty good. The controversy over antifreeze has me confused. The mechanic says our engines are dry sleeve and don't need anything but regular or extended life antifreeze automotive antifreeze. I also spoke with the local Detroit Service Manager and he confirmed the use of regular antifreeze as did James Triana. However, Brett sent me a link to a copy of the Detroit tech bulletin that states it requires the SCA or DCA additives. What do you use in your U300. Quote Selected
Re: How Much to Spend for Service on U300 Reply #35 – June 15, 2011, 07:32:01 pm Kent,Have just been reading the site relating to different coolant types, use of the right water, lawsuits for false claims etc. Check it at: Forward - DEX-COOL 2007The sleeves are only part of the picture. Radiator solder joints, water pumps, etc. are to be considered. As computers crunch the numbers, better and better products are seen on the market. The products you see today do an even better job than say, ten years ago and are easier on the environment. Brett had a perfect answer for concentrated vs. 50/50 in the jug. I have RO water here at the house as the well water tastes terrible and spots the cars. I will fill a few containers with RO and rinse the system as earlier posts. When you add the concentrate doing it this way, you can control the final mixture easily. All auto parts stores sell percentage indicators of many types so you should have no trouble getting it to 50/50. This mixture protects down to -37F so temp should not be a problem. All combustion chambers have "hot spots" where one area sees higher temperatures than the rest of the chamber. A water only or lower percentage coolant may allow the coolant to vaporize on the other side of the metal potentially causing damage or in a gasoline engine, pre-ignition. Another reason to check or replace the pressure cap (14 lb cap raises the boiling point considerably) when doing a coolant change.And last, speaking of the environment, don't leave the old coolant in an open container of any kind. It tastes good to most animals and is usually fatal if ingested. Some creatures may even chew on a plastic container to get to it. Spouses have also been known to make lemonade from it for those who speed too much time or $$ on the RV.To get to the other side of the bush, I will see what is on sale that meets the extended life and protection I need. Next week or so. Make sure to get all air out of system when refilling. Some engine/cooling systems do it better/easier than others. Out the door to photo the Robin Hood kids play. Later. Quote Selected
Re: How Much to Spend for Service on U300 Reply #36 – June 15, 2011, 09:02:58 pm Pierce, what procedure do you suggest to get the air out of the 6V92 system when changing antifreeze? Quote Selected
Re: How Much to Spend for Service on U300 Reply #37 – June 15, 2011, 10:07:40 pm Kent,I'm going to jump in here and say for the 10 years I've owned my coach I've always heard and read that 6V92s were wet sleeve and to be very particular about the coolant. For the spin-on coolant filter I use DD's "need release" to make sure the additives are up to snuff. I'm curious if I'm wrong about the wet sleeve - I hope others will chime in one way or the other.As far as getting the air out, I believe FT does it right by adding burp lines in the system. They are small hoses (they look like pneumatic hoses because they have the same fittings) that vent air pocket areas back up to the radiator (or reservoir). At lease I know my coach has these. That said when I change my coolant I do find that I need to add a little bit more after a test drive. Quote Selected
Re: How Much to Spend for Service on U300 Reply #38 – June 16, 2011, 01:30:29 am The 71 series Detroits were dry blocks and actually the same size as the 92 series in outside dimensions. As I remember, they kept the same stroke but punched out the block and put wet liners in it. I think the liners contact the block up a ways from the bottom so that may be part of the confusion. Lots of problems with the green 92s, especially turbo models, but the silvers had block, head (dog bone ID mark), water pump, aftercooling, etc. changes that made them very reliable. I think the rod/main bearings are the same size and part number as the 71 series. I have heard that oil contamination from fuel can lead to main bearings spinning in the block in the 92s that make it an anchor so watch your dipstick.We did have an 8V-71 in a new fire truck leak coolant into the combustion chamber. Bent a connecting rod on a start up and had a bit of vibration until we figured out something was wrong later that day. Replaced the rod and piston. Another had the tip of an injector blow off. Incredible black smoke out of that cylinder but the factory picked up the tab for both problems. The only other problems I heard about at the seminars were the early Jake brake models gradually loosening the fuel supply/return lines on the injectors from vibration and diluting the oil in the pan. Thought that was addressed years ago but a good reason to check the oil every day while on trips to make sure nothing is being added to what is already there in the pan. With a 19 to 1 compression ratio, they sure do start fast. No glow plugs either. Probably the reason for three start batteries. One guy was knocking Detroits to a another with one. The owner said when they get old, they age like a fine red wine. The other guy said they turn to vinegar. They did start life back in the 1930s.John,Yes, there are a couple of lines that go to the high points that might trap air and vent back to the black pressure tank with the radiator cap. Good eyes. Quote Selected
Topic: How Much to Spend for Service on U300