LXi and WideBody PTO/Pump Splines

[davidbrady]

Folks,

Some time ago I worked on and provided a solution to the early PTO/Pump spline failure that some of us see on our Series-60 equipped LX[i]'s and WideBodies. For those who don't know, the PTO and pump assembly is what provides hydraulic power to our hydraulic engine cooling fan assemblies. The PTO bolts to the transmission and spins the hydraulic pump.

The problem is that the 7/8"-13T SAE 'B' splines aren't strong enough. Going to the 1"-15T is markedly better and if cared for properly (or if wet splined) should achieve lifetimes on the order of the Allison transmissions.

Chelsea provides the 1" splined PTO and QCC provides the pump. The system is proven on our buses.

Part numbers:
The original Pump, 7/8"-13T spline: CPC 1040 CPC 030-R-2-AA-BC
The upgrade Pump, 1"-15T spline: CPC 1049 CPC 030-R-2-AF-BC

The original PTO, greasable, 7/8"-13T spine: 267XDFJP-M5GK
The upgrade PTO, greaseable, 1"-15T spline: 267XDFJP-M5GF

The original PTO, wet-spline, 7/8"-13T: 267XDFJWM5AK
The upgrade PTO, wet-spline, 1"-15T: 267XDFJW-M5AF

The 'field serviceable' 7/8"-13T, wet spline kit: 328591-141X
The 'field serviceable' 1"-15T, wet spline kit: 328591-129X

Additional part number:
The 'field serviceable' 1"-15T, greaseable and rotatable (in 30 deg increments) kit: 267XDFJPM5GH

In WaGu's trusty Document Library, you can:
click here for Chelsea PTO Documentation, and
click here for Quality Control Corp (QCC) Pump Documentation.

[Arcticdude]

A clarifying question: is the "field serviceable" a part that includes everything to change over to wet spline? If changing to a 1", you'd also need the upgrade pump and upgrade PTO, correct?

[davidbrady]

(04-29-2013 16:18)Arcticdude Wrote:  A clarifying question: is the "field serviceable" a part that includes everything to change over to wet spline? If changing to a 1", you'd also need the upgrade pump and upgrade PTO, correct?

John,

Part number: 328591-129X, converts our stock 7/8"-13T shaft PTO to a 1"-15T wet-splined (AF) PTO; i.e., the kit comes complete with a new flange, 1"-15T output shaft, bolts, seals, pressure hose, and gaskets.

The wet spline kit T's off the fluid line that's currently going into the PTO and adds a line to the flange cavity. A hole in the flange returns fluid to the gear cavity and back into the transmission.

[Arcticdude]

So add the 1" pump and you're good to go?

[davidbrady]

(04-30-2013 00:44)Arcticdude Wrote:  So add the 1" pump and you're good to go?

That's right John, add the 1"-15T Quality Control Corp Pump (CPC 1049 CPC 030-R-2-AF-BC) and you're ready to go.

It was quite a process coming to a conclusion on the PTO/Pump spline early failure. I eventually showed my worn splines to a metallurgist and a gear specialist. The gear specialist gave me a spread sheet which I've attached two copies of, one for the 7/8" and one for the 1". The spread sheets show that the 7/8" isn't strong enough. The 1" is, but with a slight safety margin. The cause of the failure is most likely fretting due to shaft misalignment along with undersize splines. There's no sign of shock loading or load reversals as I had initially thought, so prolonged engine idle isn't an issue. I spoke with a long time Chelsea tech person who said that the tolerances of the PTO are poor and have gotten worse after outsourcing manufacturing. Muncy also offers a full time PTO but word is that their alignment isn't any better then Chelsea's. So the best root cause we have to-date is misalignment which initiates fretting and overloading of the spline due to undersized splines.

If you look at the attachments you'll see the "shear stress in teeth" and "compressive stress in teeth" for the 'Fixed Spline': 1) 'compressive stress in teeth' margin-of-safety of -0.129 for the 7/8" shaft and 0.349 for the 1" shaft, and 2) 'shear stress in teeth' margin-of-safety of -0.032 for the 7/8" shaft and 0.487 for the 1" shaft. My gear guy would like to see safety margins no less than 1.5x to 2.0x. The 7/8" shaft just isn't adequate. The 1" shaft is markedly better, but it's still too wimpy to make an overall wet-spline recommendation.

Given the slight safety margin of the 1", folks will have to make their own call as to whether to go wet-spline (AF) or grease (GF).

[Arcticdude]

It looks like the 1" shaft is only .834, whereas the 7/8" shaft is .724. That would certainly explain why there's not much improvement in moving to the 1" shaft. Too bad it's not truly 1.000". Why do the OTR guys not see issues with theirs?

[davidbrady]

(04-30-2013 16:52)Arcticdude Wrote:  It looks like the 1" shaft is only .834, whereas the 7/8" shaft is .724. That would certainly explain why there's not much improvement in moving to the 1" shaft. Too bad it's not truly 1.000". Why do the OTR guys not see issues with theirs?

Ahh, but it's more than just an increase in root diameter, it's also an increase in tooth count and an increase in effective width of the engaged tooth.

Going to 1" decreases the stresses on the steel by 35% and puts us well below the spline's allowable design stress limits. The improvement is well worth the effort. The spreadsheet only requires a safety margin greater than zero which we achieve with the 1" shaft but don't with the 7/8", and there's zero price increase relative to the 7/8" splined PTO and Pump.

We're very fortunate that both Chelsea and QCC provide parts that allow us to achieve design strength and to do it within the space constraints we have.

[Itchintogo]

(04-30-2013 18:36)davidmbrady Wrote:  

(04-30-2013 16:52)Arcticdude Wrote:  It looks like the 1" shaft is only .834, whereas the 7/8" shaft is .724. That would certainly explain why there's not much improvement in moving to the 1" shaft. Too bad it's not truly 1.000". Why do the OTR guys not see issues with theirs?

Ahh, but it's more than just an increase in root diameter, it's also an increase in tooth count and an increase in effective width of the engaged tooth.

Going to 1" decreases the stresses on the steel by 35% and puts us well below the spline's allowable design stress limits. The improvement is well worth the effort. The spreadsheet only requires a safety margin greater than zero which we achieve with the 1" shaft but don't with the 7/8", and there's zero price increase relative to the 7/8" splined PTO and Pump.

We're very fortunate that both Chelsea and QCC provide parts that allow us to achieve design strength and to do it within the space constraints we have.

Luuucy... thats alot of "splining to do". Thanks for clearing that up with the science David.

[pgchin]

(to the tune of the Beach Boys lil GTO)

Lil PTO, you're really looking fine
with a brand new hydraulic pump
You're really quiet all the time!!!!

Gotta here ya tack it up now
and here your s60 whine, yeah, yeah!

OK, so I told David I would be off the forum for a week due to the holiday.
What I DID NOT tell him was why, I "inferred" the holiday. I did not want to spill the beans and jinx myself, but alas, I brought the coach in over the holiday weekend and installed the new PTO and pump, that I've only had since 4/12! Yes, the KING of procrastination and "just in time" replacement parts! Hey, don't pick on me, I road last year around with it under the bed and had the tools AND the 5 gallons of oil to do it on the road if I needed to!!!!! What's a few extra hundred pound on the drives and tags!
I am not going to focus on what size shaft, what type of lubrication system because I think we beat that topic to death and in the end it comes down to personal choice. I am going to focus on tips and techniques for install on 95-97 and all LXI s60 equipped buses in case you decide you want to do this job yourself.
First, time..... It took me 8 hours spread over 2 days, NOT including cleanup, old oil recycling, lunch breaks, etc. Now that I've done the job once, I could probably do it in about 5-6 hours, 1 day. This is FYI in case you are trying to find out the correct amount of hours a shop should charge you if you do not care to do it yourself or are not physically capable of doing it yourself. This will give you a "ballpark" idea of labor.
95-96,97-2003....... The BIGGEST difference with respect to this job and those year s60 breaks is engine cradle. The 95 and 96 engine cradle sits about 12 inches higher the the 97-2003 s60 wide bodies and LXI's. That's because in 97 Wanderlodge lowered the engine cradle to build a walk in closet in the bedroom and kept that configuration up through 2003. The reason I mention this is because it will go easier for you and you will have more room if you roll out the battery trays that hold the the house batteries. If you have a 95 or 96 AND you are the correct physical size, you can use the "sit up" position in the back of the battery box area and remove and install both the PTO and pump while you are sitting up and NOT have to work with your hands over your head on the 97-03's. THAT was a big advantage for me as I did the job myself and I'm a skinny weakling. Working with your hands over your head on your back, requires more arm and chest strength and a "second pair" of hands to help install the new PTO if you can't hold the heavy item with one hand while you screw the bolts in. Just FYI.....no deformation of ANY products here, just differences. Bottom line, you may need a second pair of hands, worst case, for the new PTO install 1 to hold, 1 to screw in the bolts. Some people have used a motorcycle tiedown strap to hold the new PTO in place but for the life of me, I could not find a way to do it where it would hold it correctly and not bend the gasket.
Before you crawl under the bus, make sure you have jackstands,the bus blocked up, etc. Please work safely under the bus with at least 2 forms of supports like jackstands AND levelers for support.
Start by draining the hydraulic oil tank (blue tank). Loosen the 2 5/8 inch bolts on the top clamp, remove both the clamp and tank top and pump the old oil out, I use a cheapy hand pump from Harbor Freight, about 5 bucks for both pump out and new in.....worked great!
Once the tank is as dry and you can get it, GET CARDBOARD and an oil pan!!!!!! Locate the pump. It has a high pressure side (smaller top line) and a 1 1/2 inch feed line (lower line). The top line you can remove at the pump, the feed line (lower) you cannot get a wrench on it (2 1/4"). The lower line has a upipe and about 1 1/2 foot of 1 1/2" rubber line. It attaches to another steel pipe that comes from the tank. Detach the bottom line at that joint and the upper line at the pump. Remove the 2 bolts holding the pump to the PTO and you can then remove the pump with the upipe and 1 1/2 foot of flexible hose. CAUTION, when you break that lower hose loose, no matter HOW LONG you let the line bleed down, when you remove the pump, that upipe STILL has a ton of oil in it and you are going to get an oil bath if you DO NOT get out of the way!!!!!!! That's what the cardboard and oil pan is for. Place cardboard under the entire engine area and use the oil pan under the joint so when you pull the pump, you can angle the pump and upipe to the pan to drain the residual oil. Don't forget to remove the upipe clamp on the tranny bracket by the top back of the tranny...3/8' bolts and nuts BEFORE you slide the old pump and PTO apart.

Now, this where I "stopped for the day". Put the top back on the tank, used zip lock bags over the exposed hoses (2) and taped them with blue painters tape so the system would not be compromised by water, rain, etc. Once you seal the 2 hoses with zip bags and put the top of the tank back on, you are good to go..... if you are working in a GARAGE like SOME people I know you have no worries, but us poor people doing it on the driveway or in a campground need to take precaution against intrusion!
I stopped here because I needed to reuse the hose fittings from the old pump and install then on the new one with new orings. I DID NOT have a
vise or any way to do this, no matter how big a wrench or sleg I used I could NOT break those old fittings off the old pump. So, I took both the old and new pump to my local hydraulics guy and for 15 bucks and 10 minutes of his time WALLA... done!!!! And I saved my knuckles and hands!
Once I did, this, I came home and reattached the upipe and flex hose to the new pump taking care to make sure I had the upipe at the correct angle as the pump sits at about a 45 degree angle on the PTO and the upipe mounts to a tranny bracket level so the upipe has to be vertical when the new pump mounts. So how did I do this? Well, I purchases one of these:
http://www.harborfreight.com/24-inch-com...96791.html
BEFORE I removed the upipe off the old pump I placed it on a level floor and put a a small level on it to insure it was level. I used the tool above, removed the 45 degree clamp off and moved the 9o degree clamp to the bottom. Using the level in it I now had the metal ruler sticking straight up in the air next to the upipe and the pump level. I got a wooden yard stick, placed it parallel to the upipe and moved the tool above to the yard stick. Using the semi circular clamp, I locked the yard stick to the upipe while both the tool and pump were level and tightened down the semicucular locks on the tool and now I had the upipe angle! I then removed it and reversed the process to install it on the new pump, when I installed the pump, the upipe was perfect!
Day 2:
So with the the new pump and old upipe mounted to it and ready to go I focused on removal and installation of the PTO...... pretty straight forward just follow the directions that come with the PTO. Removal of the old one is no big deal, 8 bolts, leave the top center for last, break'em all loose first as they are lok tighted in, then hold the pump in 1 hand and remove the top center bold LAST as per the instructions. Remove the tranny feed line at the transmission and the 1 clamp BEFORE you pull the old pump so the tranny line comes down with the old pump. You will want to replace that line so you can order the correct one with the PTO or have your local Hydraulics shop make one up for you. If you choose the latter take a picture of the tranny end lines FIRST and bring it with you so they can give you the correct fittings, the area is a little tight!!!!!!
Once you have the old pump down mount the new tranny line to the new PTO BEFORE you install it AND the flange PLUG as the new flange on the PTO has a hole in it. Then mount the new gasket to the tranny and guide pins, ridge facing the installer and mount the new PTO. Hold it in with 1 hand or a strap or buddy while you put the new top bold in. Once the top bolt is in, you can relax a bit and install the remaining all hand tight. BE CAREFUL with the new gasket...... you do not want to bend it and it has a tendency to have gravity act on it and move while you are trying to line up the new PTO on the guide pins per the instructions. Here's an old mechanics trick... get a little wheel bearing grease and dab a TINY DAB on the top (2) and sides(2). DAB A SPOT, DO NOT COAT the darn thing!!!!!!! The wheel bearing grease DAB's will help hold the new gasket in place on the tranny and guide pins and help you defie gravity while you align the new PTO on the guide pines and bolt it in place. Now you have all 8 bolts in you can torque them down according to the instructions. Cross torque them 1 top, 1 bottom, side to side,etc and go in increments. 10lbs, 20,lbs, 30lbs, final lbs as you are working with an aluminum tranny and you'll get a better result! The bottom center bolt is tough to get a torque wrench on so you may have to wing it here or use a universal socket. Won't be prefect but is should do the job. Install the new tranny line on the tranny and clamp, check the line for clearance and spacing and the PTO is IN!!!!
Now all that remains is attaching the new pump and upipe to the new PTO. Very easy, align the shafts, slide it in, use 2 bolts and tighten the pump to the PTO flange!
Attache the 2 lines, fill the tank with oil, change the 3 filters in the tank, start the bus up for 15 seconds, turn off and recheck the tank, then start it up and run it for about 15 minutes. The fan should start turning right away or on the second start.....mine ran right away!. Road test and recheck the tank for correct level the next morning and your fittings for any seepage, etc.
FYI for those using grease lubrication, grease the shafts on both the new PTO and pump before you install them.
That's it!!!!!! Good luck and post if I've not been clear and I'd be happy to answer your questions. Also for those of you who have done this please add any tricks you may have used I've forgotten. I also want to thank a friend of mine, Mallie, who helped me get the pump and gave me some intital tricks you see here, a good pal and friend of the wanderlodge community!

After thoughts:
If you have a GOOD hydraulics shop AND TIME, then you could probably save some bucks by just removing the old PTO and pump and having a local shop rebuild them for you. We have a great one here in FL, that services most of the counties, fire departments, businesses, etc. They are located in Tampa, Daytona and Jacksonville...... Central Hydraulics Great guys and gals!!!!! Time was not a luxury for me as I can only have the bus at the house for 36 hours and did not want to do the job in the storage yard so I purchased new. I found out LATER that they offer 2 business day turn around on rebuilds so had I asked First BEFORE I purchased new, I would have probably risked a letter from county code enforcement and just let the bus sit a week in the driveway and had my old ones rebuilt..... Lesson learned here is to ASK First!!!!!!!!! Also I had an old 265 PTO, EXACTLY like a 267 EXCEPT the end cap did not allow you to grease the shaft..... BUT the shaft was drilled for grease!!!!!!! If I knew that I could of changed the end cap and added a fitting!!!! Since mine was NEVER greased since it was new, I got 19 years and 90,000 miles out of it! An engineer at Chelsea told me anything over 30,000 on a 265 was good! I still had some teeth left and about another 1-3 years but I am glad I changed it now. Also when I pulled the old pump from the old PTO the amount of metal filings and rust over the 19 years that came out could fill a bathroom dixie cup!!!!!!!!! Holy cow!!!!!!!!! Just FYI.................

[davidbrady]

Wow Pete! BTDT!

I know what a great feeling it is to have a new PTO/Pump unit installed! Congrats! I'm sure you're enjoying the smooth and quiet operation that comes with new. Are you also going to look into your fan speed control? It may be worth while to take a photo tachometer to the system to get a baseline for speeds. At this point the only items that could impact fan speed are the controller and the fan motor.

I couldn't agree more about the 2 1/4" u-pipe and flexible hose couplings. I couldn't budge one of them. I also hauled mine down to my local hydraulics shop for them to separate the couplings. They clamped it to their mongo vice, grabbed a 4' cheater pipe, and brought over their forklift to apply pressure the the cheater bar! It popped! I don't know what's up with those large connections - there may be some galling going on that welds them together.

On the LXi style lowered chassis models I was able to hold the combined PTO/Pump assembly up with one hand while I positioned the bolts with the other. In fact, I did it twice, which is usually my luck. The first time I put the PTO/Pump assembly together after topping up with fluid and starting the coach I noticed that the seal at the PTO shaft was leaking (at the grease fitting side). So, I drained the fluid a second time, took it all apart, brought down the PTO/Pump as a single assy, installed a new seal and lifted it back up with one hand and bolted it in place with the other. Don't mess with me, I'm a Hercules! Not!

Way to go Pete! I'm glad you go that job done!