Busted Tranny Housing

Topic: Busted Tranny Housing (Read 1896 times) previous topic - next topic

Re: Busted Tranny Housing

Reply #25 – April 17, 2019, 10:27:04 am

Quote from: Old phart phred – April 17, 2019, 02:15:01 am

I beg to disagree with your opinion, as u joints roll rover center when not inline, and my coach drive shaft is only about 16" long. So 1% to 3% total from the axle centerline to the to the transmission tailshaft has to be made up as the suspension moves up a down a couple of inches up and down from design ride height. For this reason I believe rear ride is important.

No, the angle coming out of the rear end the the angle coming out of the transmission never changes as they remain parallel when the rear end travels up and down. The driveshaft angle changes but not the extended centerline of the pinion and input shaft for the tranny. For a conventional driveshaft (no constant velocity joint) 1 degree is ideal with 3 or 4 degrees the limit for long joint life. Note how to calculate driveshaft angle in the second image attachment.

So, while it's nice to have that 1 to 3 or 4 degree driveshaft angle (not pinion or input shaft angle), it will operate at angles exceeding this but it's not likely in our coaches while traveling down the road. Note the calculation for the real angle in the second image. It would seem much greater but when the measured 7 degree angle is actually calculated in relationship to the U-joints, it's only 4 degrees. While it looks like a lot, when you calculate it, it's only about half that much.

With proper rear end geometry, the rear axle assembly will NOT rotate as it travels up and down over bumps, etc but remain parallel with the centerline of the transmission output shaft.

Pierce

Re: Busted Tranny Housing

Reply #26 – April 17, 2019, 10:31:30 pm

I believe this whole episode started back when we bought the coach. I immediately had the chassis serviced and the mechanic found some slop in the output shaft. After some research, I found that Allison had issued a service bulletin that the retainer torque, for the tapered roller bearing at the end of the output shaft, might not be properly torqued. I gave the new torque spec to the mechanic, but he said that was way too tight. He retorqued it to what felt 'right' to him.

Fast forward 5 years and 16K miles.

I tend to think the retainer loosened again and that the driveshaft 'worbled-out' the seal which then resulted in profuse oil loss.

We pulled into a RV dealership in Gilbert AZ. They suggested that they could take it to a Freightliner dealer and have them repair what I was fairly certain was the culprit. "Were'nt there some posts a few years back about the seal area on the trans wallowing out and causing a problem?" I appreciated their offer and took them up on it.

Fast forward a few days.

We went home to Augusta, KS as we just couldn't reconcile ourselves to a lengthy motel stay with two hounds...1200 miles from home...and tax time upon us.

Fast forward a few more days.

Freightliner called and said that the driveshaft had jammed into the transmission housing, and that the housing was damaged to the point where it would no longer retain a seal.

After some deliberation, I recalled that the RV dealer employees ALWAYS dumped the air to set their coaches lower for easier entry by potential customers. I recalled that it was just a reflex action on their part. They always did it.

So my guess is that when this RV dealer had an employee shuttle our coach to the Freightliner shop, he undoubtedly dumped the air.

At this point, I need to tell you that the air system in that old U295 is no longer robust (still easily meets DOT). It takes a while to get up to 110 psi. The old coach won't go to ride-height until you release the brake after hearing the pop-off valve. However, the brake releases arounf 60 - 75 psi if you wanted it too.

My quess is that the mechanic...always in hurry...released the brake as soon as the whistle shut off...not realizing that he hadn't attained ride-height...and drove (not crept) the dumped coach over the door threshold and caused the ensuing damage.

I've discussed this...over the phone...with James at FOT. He agreed that 'MIGHT' have caused it.

Anyway, I won't be sleeping too good tonight after reading some of your reponses.

Larry

Re: Busted Tranny Housing

Reply #27 – April 17, 2019, 10:39:35 pm

I seem to remember Al & Sue McMurray had the same issues after MOT ferried their coach from southern Oregon to Nac to consign for sale......... It also was a 36 footer..

Re: Busted Tranny Housing

Reply #28 – April 17, 2019, 11:26:37 pm

Regarding Xtreme...shortly after we purchased the coach in 2014, the bay door over the propane tank popped open...while driving...and damaged it. Ripped the rivet holes along the hinge-line like a failed zipper.

When we went to attend wife's driving school, Xtreme rebuilt it for us. After installing the repaired door, the fiberglass tech offered us a quick look-over (at no cost) for other problem areas. He then pointed out how the bulkhead repair had already been accomplished on our coach.

The bay door damage...and the bulkhead repair...is really, really sore point with me. Has NO ONE...at FOT...ever heard about such a thing as minimum edge-margin for fasteners? Grrrrrrrrrr...

Re: Busted Tranny Housing

Reply #29 – April 17, 2019, 11:35:48 pm

Your theory about the tech driving the coach before acheiving ride height sounds plausible. Tire contact with the top of the wheel well by the drive wheels would also try to force the axle back towards the tranny. At any rate, you will sleep better when you know the root cause of the damage, so I hope your investigation brings you that closure. Everything looks better after a good nights sleep, so I hope you get that tonight!
Don

Re: Busted Tranny Housing

Reply #30 – April 18, 2019, 03:02:40 am

Larry,we all emphasize with you and wish this did'nt happen but you may never know the cause just the result of the problem.
Hate to say it but the root cause may be the air system not building enough air and loosing air.The coach is fixable,is there
any way your insurance would pay for a tow to another shop in case your not happy with this one?If the guy did not torque to
the right spec and his feel was off that's probably what happened with the oil loss.When you finally get the coach running make
an appointment with HWH in Iowa and they will go over your system free of charge,won't fix it for free but tell you what's wrong.
Keep us posted and what year is the coach.

Re: Busted Tranny Housing

Reply #31 – April 18, 2019, 11:12:55 am

Quote from: U295 Owner – April 17, 2019, 10:31:30 pm

I gave the new torque spec to the mechanic, but he said that was way too tight. He retorqued it to what felt 'right' to him.

. . .

My quess is that the mechanic...always in hurry...released the brake as soon as the whistle shut off...not realizing that he hadn't attained ride-height...and drove (not crept) the dumped coach over the door threshold and caused the ensuing damage.
I've discussed this...over the phone...with James at FOT. He agreed that 'MIGHT' have caused it.

Anyway, I won't be sleeping too good tonight after reading some of your reponses.

Larry

I'm sorry for your loss, and you might understand my paranoia when dealing with outside "help."

A past friend of mine, Tony, owned a 1959 Cadillac Eldorado Biarritz Convertible and this automobile too had air bag suspension powered by a vacuum operated duplex air compressor. The final blow was a simple engine oil change at the dealership where the driver didn't want to wait for the air suspension to rise from its rest and crunched the engine oil pan on the lip of the garage.

This stuff happens more often than you think it does.

Let us hope that the Freightliner shop is more professional.

Re: Busted Tranny Housing

Reply #32 – April 18, 2019, 12:31:02 pm

John, the coach is a 1995.

I really don't blame Freightliner for the situation. Most coaches, in that age range, don't level with air. I suspect that the tech (mostly used to working on trucks) may likely have never encountered such a situation. The shop has a good favorability rating, and they are quite cordial in keeping me abreast of what is happening.

There is much more to my story. My wife and I had been contemplating upgrading to a larger and newer coach for some time. This dealer had a consignment coach that came fairly close to matching our 'want list', so we bought it. However, it was a bit like a shotgun wedding. The 1995 has to be fixed before I can consign it in good conscience...assuming that I, indeed, do want to consign it. Turns out that the grass is always greener on the other side of the fence, and the newer coach isn't exactly paradise either. We are actually mulling over consigning the newer (2002) coach and keeping our old 36' 1995.

For example, I had always assumed that 450HP would move a 42' foot coach up the on-ramp rather assertively. It doesn't. It whimpers up the on-ramp. The C8.3 moves our old 36-footer much more assertively. Obviously, the 5.13 axle ratio on the 1995 is a HUGE factor when compared to the 3.91 axle ratio on the 2002 coach.

Anyway, I'm sure the epilogue on my gravestone will read that there is one thing worse than becoming old - becoming old and stupid!

Larry

Re: Busted Tranny Housing

Reply #33 – April 18, 2019, 01:14:16 pm

Quote from: U295 Owner – April 18, 2019, 12:31:02 pm

For example, I had always assumed that 450HP would move a 42' foot coach up the on-ramp rather assertively. It doesn't. It whimpers up the on-ramp. The C8.3 moves our old 36-footer much more assertively. Obviously, the 5.13 axle ratio on the 1995 is a HUGE factor when compared to the 3.91 axle ratio on the 2002 coach.

Anyway, I'm sure the epilogue on my gravestone will read that there is one thing worse than becoming old - becoming old and stupid!

Larry

I don't understand the infatuation with acceleration.* Never mind the number of long trips I've taken in antique automobiles, I once spent three summers driving my freshly built 1926 Ford to antique auto shows in New England. What could have taken 5 hours now took my 12 or more hours travel time. I enjoyed the day and gained an appreciation for just how much smaller our world has become.

That being said, recognizing that you aren't happy with a recent decision and having the ability to change your mind makes you intelligent.

*I have a very fast motorcycle for that foolishness.

Re: Busted Tranny Housing

Reply #34 – April 18, 2019, 01:16:13 pm

Larry,

You should have your fuel pressure checked as your M11 40 footer should not let much grass grow underneath it. Something must be amiss that perhaps other owners may want to comment on.

I followed a 36' U320 M11 and while we were up at a little over 5000 feet, we had to have just the right upgrade for our Detroit to barely creep up on the other coach. The rest of the time, the six speed U320 was just faster, especially from stop signs where the perfect first gear in the U320 had them half way down the block before I crossed the intersection with our four speed.

Your coach should do almost as well as a 36 footer so get it checked out.

Pierce

Re: Busted Tranny Housing

Reply #35 – April 18, 2019, 02:13:27 pm

I have no infatuation with acceleration...though it makes me sweat when a car bears down on me at 75 mph...driver texting instead of having eyes on the road...while I'm still doodling along at 25 mph.

Re: Busted Tranny Housing

Reply #36 – April 18, 2019, 02:32:21 pm

Whitch coach you keep is up to you alone to choose,pros and cons for both ways.I would put it for sale here with your low price and see what happens before consignment,you can always try and sell without the trans repair as long as you disclose the problem.

Re: Busted Tranny Housing

Reply #37 – April 18, 2019, 08:08:50 pm

Quote from: Pierce & Gaylie Stewart – April 18, 2019, 01:16:13 pm

Larry,

You should have your fuel pressure checked as your M11 40 footer should not let much grass grow underneath it. Something must be amiss that perhaps other owners may want to comment on.

Pierce

Well if you want to go down that road, fuel filters can restrict the fuel flow enough to reduce power. 450 HP is a lot of fuel flow.

Re: Busted Tranny Housing

Reply #38 – April 18, 2019, 11:00:27 pm

Larry, we have a 40'320 w/450 and it will move right along when you want it to, as posted above I would be checking fuel flow and pressure then possibly new fuel filters
Chris

Re: Busted Tranny Housing

Reply #39 – April 18, 2019, 11:06:22 pm

And alot of intake and exhaust flow. Bigger rotating parts to slow acceleration. Colin Chapman nailed it with "simplify and add lightness"

Re: Busted Tranny Housing

Reply #40 – April 18, 2019, 11:31:30 pm

Is the 42 footer a Foretravel? If so, that 450 hp has to move a lot more weight than your 36 footer with the 300 hp 8.3 Cummins. If it is not the ISM in a Foretravel, and an ISL, in another brand, torque will be lower and acceleration could very be slower than your 36 footer. Horsepower to weight ratio is important.

Re: Busted Tranny Housing

Reply #41 – April 19, 2019, 12:50:30 am

Yes, the 42-footer is a U320 with an ISM. Yup, the 36-footer with a C8.3 has a better hp/weight ratio.

Re: Busted Tranny Housing

Reply #42 – April 19, 2019, 12:57:19 am

Quote from: U295 Owner – April 19, 2019, 12:50:30 am

Yes, the 42-footer is a U320 with an ISM. Yup, the 36-footer with a C8.3 has a better hp/weight ratio.

Had a 34 footer with the ISC 350, faster than my 40 footer with a 500 hp ISM. Can't mess with physics, talking 14000 lbs difference.

Re: Busted Tranny Housing

Reply #43 – May 02, 2019, 02:44:04 pm

Had the housing crack on one of our install trucks.. when they bolted the torque converter down they cracked the housing.. I welded it up and put it back into service. Dont know if that is possible but a cheap fix

Re: Busted Tranny Housing

Reply #44 – May 03, 2019, 12:30:53 am

Larry when I first drove our m11 I was unimpressed at the power.

Long list of changes made it much better. But we are at 36,000 pounds combined.

You certainly weigh more.

The 450 can probably be raised to 500hp. Brads brother Dave did his.

Exhaust, fan drive controller, good batteries, good alternator, solar to turn off the alternator during a drive, valve adjustment, cam position sensor, altitude sensor replacement, blue tech air filter, low rolling resistance tires, synthetic oil in wheel bearings.

Everything together made a fairly large difference in the engines ability to stay in gear up grades versus downshifting.

But at 10k more weight I would think it's still not impressive.

Brads brother Dave had friends at the Cummins dealer who may have bumped his power up even more somehow.

He's gone and no one knows. But the 500 hp is possible on the ISM

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