Allison Transmission Dead?

[cmduran]

I posted this on the Class A motorhomes forum and someone suggested I post it here.

I have a 98 Holiday Rambler Endeavor with a Cummins engine and Allison transmission. It has 40K miles on it. Periodically the transmission would not go into gear, then it would. So I took it to a big truck center here in San Antonio, with certified Allison mechanics. It had been giving a 2511 code, so everything I read led me to believe the problem was electronic. But the mechanic says it's internal, probably the C5 clutch or possibly a piston seal. He hooked up the computer for me and explained his diagnose. He has 25 years experience and pretty much convinced me that he was probably right. I'm still awaiting an estimate but I suspect it will be more than the whole RV is worth and I'll have to sell it for salvage.

Anyway, just thought there might be some folks who would want to comment....or at least offer condolences.

[Old Scout]

....hard to argue with that much experience.....sorry about your loss!!!!!!

[cmduran]

Originally Posted by Old Scout

....hard to argue with that much experience.....sorry about your loss!!!!!!

LOL. Thanks.

[Arizona]

Maybe ask him to help you find a replacement transmission. Usually that’s the last thing to fail.

[CoCoDave]

Like Old Scout said, it's hard to argue with that much experience. That said, given the cost of your options as they exist today, I'd get a second opinion.

Good luck!

[NHRA225]

Is this an MD3060 ?
If so
Code>Code 2511 means the output speed sensor has a zero speed reading. Check the speed sensor and connection, the ohm reading should around 300 ohms. Also check the ECU connectors. Make sure they are tight,clean and undamaged. Check the fluid level and check wiring to the sensor has no opens, shorts between wires or shorts to ground.

[BigSkyBob]

Originally Posted by NHRA225

Is this an MD3060 ?
If so
Code>Code 2511 means the output speed sensor has a zero speed reading. Check the speed sensor and connection, the ohm reading should around 300 ohms. Also check the ECU connectors. Make sure they are tight,clean and undamaged. Check the fluid level and check wiring to the sensor has no opens, shorts between wires or shorts to ground.

Wow, could it be that simple? Let's hope so. Good info nevertheless.

[NHRA225]

Originally Posted by BigSkyBob

Wow, could it be that simple? Let's hope so. Good info nevertheless.

Nothing is ever that simple on my old Bird !

[YC1]

Originally Posted by NHRA225

Is this an MD3060 ?
If so
Code>Code 2511 means the output speed sensor has a zero speed reading. Check the speed sensor and connection, the ohm reading should around 300 ohms. Also check the ECU connectors. Make sure they are tight,clean and undamaged. Check the fluid level and check wiring to the sensor has no opens, shorts between wires or shorts to ground.

It never ceases to amaze me the talent and vast knowledge base this forum has.

[NHRA225]

Originally Posted by YC1

It never ceases to amaze me the talent and vast knowledge base this forum has.

I'm not knocking the OP's Mechanic but an Allison with only 40,000 miles on it should not have seal or clutch issues. on the other hand a 1998 coach with only 40 K miles has been sitting somewhere for a very long time. who knows?

[cmduran]

Originally Posted by NHRA225

Is this an MD3060 ?
If so
Code>Code 2511 means the output speed sensor has a zero speed reading. Check the speed sensor and connection, the ohm reading should around 300 ohms. Also check the ECU connectors. Make sure they are tight,clean and undamaged. Check the fluid level and check wiring to the sensor has no opens, shorts between wires or shorts to ground.

Thanks for the comment. Everything I had read led me to believe that my problems were likely to be electronic. He said that was true and that most of the time, when he repaired Allisons, he replaced wiring, sensors, etc, but he showed me specifically with his diagnostic software how that was not the case with my issue. I should have said in the OP that I had initially taken it to another place and they replaced the sensors, which didn't solve the problem. Their final analysis was that the problem was likely internal. So I took it to the Allison specialist for a second opinion. I suppose there is always the possibility that he was wrong, but I had little doubt about his qualifications or sincerity.

[cmduran]

Originally Posted by NHRA225

I'm not knocking the OP's Mechanic but an Allison with only 40,000 miles on it should not have seal or clutch issues. on the other hand a 1998 coach with only 40 K miles has been sitting somewhere for a very long time. who knows?

That was my thought also. These things might stay on the road for several hundred thousand miles in a truck. In fact, the tow truck I road with on the way to the repair place had an Allison Transmission with over 400,000 miles!



But, yes, it had sat a lot. I can see from the service records that most of the miles were put on it in the first few years that the original owner had it. It had been sitting for about 1 1/2 yrs before I got it.

[cmduran]

Originally Posted by cmduran

That was my thought also. These things might stay on the road for several hundred thousand miles in a truck. In fact, the tow truck I road with on the way to the repair place had an Allison Transmission with over 400,000 miles!



But, yes, it had sat a lot. I can see from the service records that most of the miles were put on it in the first few years that the original owner had it. It had been sitting for about 1 1/2 yrs before I got it.

But I should add that when the tow truck was taking me back to my car, he couldn't get it out of first gear - LOL. It would have provided some much need comic relief if the tow truck had had to call a tow truck.

[cmduran]

The estimate came in lower than I thought it might, so I'm going to have them do what needs to be done. There's really not much choice unless I take a big loss by selling it as is. I guess you can pass the point of no return with these things, huh? Metaphorically and literally.