Community Forums

RV-Writer · 02-05-2017, 12:10 PM

Having an issue on my transmission and hoping you all have some advice.

They replaced the TCM because it was causing a no start issue. Rig starts fine now, but it is a hard shifting son of a gun. I didn't notice a hard shift on my test drives. I was running at 65mph and hit a slight hill with cruise control set. It automatically shifted to 5th and had the hard shift also hard when it shifted back to 6th. Drove about 75 miles and didn't seem to get any better.

Turned on exhaust brake at one point and that seems to be dramatic as well. I didn't look to see if the transmission was downshifting while using the exhaust brake - does the tranny downshift with exhaust brake? It was very dramatic and seemed like it was hard shifting. Any thoughts?

Wondering if I should take it back to the shop under parts and labor warranty to adjust programming on the new TCM?

6 speed MD3060 Allison

tinstar 1114 · 02-05-2017, 01:06 PM

It sounds like you're going to have to take it somewhere to fix it. If the shop is competent I would let them do it unless the trip is too far. They broke it, they should fix it.

Davidjeff · 02-05-2017, 01:29 PM

I am not rear familiar with Allison transmissions but I am with current light truck car. Here's a thought, if you did not have a problem prior it may just need to relearn the shift points. You may try disconnecting battery power and waiting 15 minutes then reconnect and slowly cycle thru park to reverse to neutral to drive and back through to park. Do this 3 times pausing in each selection for 10 seconds then drive the coach light throttle allowing it to shift to highest gear and slowly come to a stop. Do this 3 times gradually increasing the throttle to normal accel. Some vehicle have to be taught and some have to have the memory erased before teaching.. if it still acts up then go to a service center

RV-Writer · 02-05-2017, 01:53 PM

Thanks - I have it in outdoor storage right now. Will go out this week and give it a try. 75 miles to the dealership/repair shop with a toll road

sent the mechanic a note asking his opinion.

greystroke · 02-05-2017, 01:59 PM

Since I live in Florida and normal travels is in a 600 mile area I don’t have shifting problem on level road but when I venture north and get into hills I may experience rough shifting. This occurs normally in 5th an 6th gear in hilly areas such as an Auto downshift on the hill and then back to upper gear. What I do is manually select a lower gear to eliminate unnecessary up and down shifting. The control panel has two windows, “gear achieved” and “gear selected” If you select a gear with the arrows then it won’t upshift above what you selected. this will cut down on a lot of hard shifts

You may have an economy mode. Makes sure you only use it for level ground

So I just can’t tell you if your shifting is normal without being there but the MD3060 is not the smoothest transmission.

When the exhaust brake is on it will change shifting when you remove your foot from the accelerator. Again if your driving on grades you may want to “select” a lower gear to prevent excessive shifting.

Also make sure your oil is ok not by dipstick method. Use the shift control panel.

Maybe it would be worth a trip to Allison for a check.

Mr_D · 02-05-2017, 02:12 PM

TCM needs to lean your driving habits. It'll shift hard till then, but I'm not sure how long it should take.
Economy more is most efficient in rolling hills where it's shifting up and down, otherwise it makes no difference. The economy mode delays the shifting under high throttle conditions so it doesn't shift down at each little hill.

greystroke · 02-05-2017, 02:12 PM

Jim

Did you get the tranny oil changed??? If it is the wrong oil it would cause rough shifting. Only use Transynd or Allison certified oil. Wrong oil could ruin the tranny!!!

RV-Writer · 02-05-2017, 02:12 PM

Quote:

Originally Posted by greystroke

Since I live in Florida and normal travels is in a 600 mile area I don’t have shifting problem on level road but when I venture north and get into hills I may experience rough shifting. This occurs normally in 5th an 6th gear in hilly areas such as an Auto downshift on the hill and then back to upper gear. What I do is manually select a lower gear to eliminate unnecessary up and down shifting. The control panel has two windows, “gear achieved” and “gear selected” If you select a gear with the arrows then it won’t upshift above what you selected. this will cut down on a lot of hard shifts

You may have an economy mode. Makes sure you only use it for level ground

So I just can’t tell you if your shifting is normal without being there but the MD3060 is not the smoothest transmission.

When the exhaust brake is on it will change shifting when you remove your foot from the accelerator. Again if your driving on grades you may want to “select” a lower gear to prevent excessive shifting.

Also make sure your oil is ok not by dipstick method. Use the shift control panel.

Maybe it would be worth a trip to Allison for a check.

Thanks Tom. How do I use the control panel to check the fluids? I am going to see what an Allison shop will charge me to service the tranny. If I can find one in Denver area. My first shift up to 6th when I pulled out of parking lot at dealership was rough. On flat terrain. But I wasn't looking at whether it was any particular gear attained that was rough. Never touched the economy button. Will have to see how that works too LOL gotta love the learning curve!

Mr_D · 02-05-2017, 02:18 PM

Quote:

Originally Posted by greystroke

Jim

Did you get the tranny oil changed??? If it is the wrong oil it would cause rough shifting. Only use Transynd or Allison certified oil. Wrong oil could ruin the tranny!!!

Dexron III used to be the Allison approved transmission fluid until they came out with the far better TranSynd. In fact some Allisons used regular engine oil.
Just be sure to use TES-295 approved fluid, not necessarily TranSynd.

RV-Writer · 02-05-2017, 02:22 PM

I don't think they changed transmission fluid. It isn't on the work orders at any rate. I think Allison shop is calling my name - dang it LOL. Thanks All for the tips and guidance

RV-Writer · 02-05-2017, 02:37 PM

Looks like the dealership I bought it from and did the TCM swap is an Allison authorized center. Will see what they say about bringing it back to them for warranty work and see what a service will cost for oil and filters etc...

1 year parts and 90day labor warranty on the TCM so hopefully it won't cost me anything

greystroke · 02-05-2017, 02:55 PM

Quote:

Originally Posted by RV-Writer

Thanks Tom. How do I use the control panel to check the fluids? I am going to see what an Allison shop will charge me to service the tranny. If I can find one in Denver area. My first shift up to 6th when I pulled out of parking lot at dealership was rough. On flat terrain. But I wasn't looking at whether it was any particular gear attained that was rough. Never touched the economy button. Will have to see how that works too LOL gotta love the learning curve!

Ok Jim attaching instructions. Also sent you a list and link of Allison approved fluids.

oldguy70 · 02-05-2017, 03:08 PM

When you use the exhaust break it will shift down and keep shifting down as you slow down. After I changed the oil in the tranny using transynd the tranny shifted way smoother

RV-Writer · 02-05-2017, 03:12 PM

Quote:

Originally Posted by greystroke

Ok Jim attaching instructions. Also sent you a list and link of Allison approved fluids.

Thanks Tom - I will update once I get some answers from dealer. Think I will get the tranny serviced a sap with transcend oil just to be on safe side. I am hoping it is a combination of the TCM learning and the "unsmooth" Allison that you experience. Either way, the shop has a 90 labor and 1 year part warranty on that new TCM which I think would cover the TCM programming. Should know something end of week I hope.

Got both documents. I will check the oil status using shifter panel Wednesday. Really appreciate it.

Jim