Community Forums

PKontheroad · 08-19-2009, 07:21 AM

04 Workhorse. Climbed steep hill from camp to main rd. Unit not fully warmed. Outside temp around 70. At top of hill, transmission failure light came on. Rig was in L2, shifted to D & rig barely moved. Reading later, I figure I was in Limp Mode. Got to shoulder, shut down, waited a minute & restarted. Transmission failure light off. Put rig in D & took off. Operation seemed normal. Drove about 30mi & stopped at rest area. Checked fluid. Approx 1/4 qt low. Added fluid (Mobil 1 syn) & drove additional 100mi to camp. Climbed several fairly steep hills & geared down on descents. No more problem.

Heading to Calif, wondering about mountains. Was this a one time thing?
My thinking: Unit was not fully hot/slightly low fluid level/fluid to rear of tranny due to incline. Was cause merely low fluid?

Appreciate any help

speed racer · 08-19-2009, 07:56 AM

It would be good to know 1# how many miles on unit. 2# have you had the fluid and filters change on trans. 3# do you tow a car. Without knowing it sounds like both tranny filters should be changed.

PKontheroad · 08-19-2009, 08:08 AM

45k miles, tow Honda CRV, switched to Mobil 1 syn & new spin on filter at 25k

Fred and Bonnie · 08-19-2009, 03:50 PM

When you noted the 1/4 qt low, was that below the "Hot" zone or added to reach the top of the "Hot" zone? The reason I ask, when I fill to the top of the hot zone and pull long hills, I "Blow" fluid out the vent, not a good sight to leave a smoke screen.

BTW, if that was the first fill with Mobile 1, and it's been two years, since the change, I would change the fluid to ensure a 100% concentration.

Fred

PKontheroad · 08-19-2009, 04:10 PM

It was 1/4 qt below top of hot zone. No blow out yet. Plan to drain & refill this winter as soon as I can set somewhere long enough. Check same post on Allison section. Former owner had same problem & it was tracked to low coolant????

morninghill · 08-21-2009, 10:37 PM

Are you using Mobil Delvac Synthetic ATF? I thought Mobil 1 was engine oil, not trans fluid.

Oemtech · 08-22-2009, 05:12 AM

Mobil makes both a Dex III Synthetic fluid for those transmissions that were filled with Dex III and TES 295 Synthetic Allison approved Transynd for the later models.

I have the Mobil 1 Dex III running in my Allison 5 speed with no problems. Come spring I will switch to Transynd in the spring.

DriVer · 08-22-2009, 06:06 AM

Quote:

Originally Posted by morninghill

I thought Mobil 1 was engine oil, not trans fluid.

Apparently they have an entire family of Mobil Delvac synthetic oils and lubricants.

speed racer · 08-22-2009, 08:10 AM

Quote:

Originally Posted by PKontheroad

45k miles, tow Honda CRV, switched to Mobil 1 syn & new spin on filter at 25k

You might want to check but I do beleive their is a filter in the trans oil pan also.

Oemtech · 08-22-2009, 10:21 AM

Quote:

Originally Posted by speed racer

You might want to check but I do beleive their is a filter in the trans oil pan also.

But, it is only change on tear down according to the doc.

EngineerMike · 08-22-2009, 11:49 AM

OP's problem sounds like a brain fart. That happened to me twice on a P30 chassis w/L480E transmission. For whatever reason, the tranny went into limp mode and wouldn't shift above 2nd (or maybe 1st, that setup didn't have a gear-selected indicator). W/shut-down & restart, problem disappeared. Haven't heard of that happening w/an Allison, but anything is possible in an electronic world.
Maybe Microsoft did the programming on some part of the drivetrain, and vehicle needs to be shut down & rebooted periodically?

DriVer · 08-22-2009, 12:46 PM

Quote:

Originally Posted by EngineerMike

Maybe Microsoft did the programming on some part of the drivetrain, and vehicle needs to be shut down & rebooted periodically?

I'm sure that you are not too far off the mark because that has been my experience.

A very brief shutdown and restart appears to clear up a lot of issues which often don't repeat.