Allison Tran

[williamp321]

I have erratic shifting with my 8.1 Allison 1000 tran. 50mph and above my tack shows 2200 to 2500 up and down from my tran shifting. Any one else every had this problem with this Allison 1000 tran.

[rgatijnet1]

Also it is a good idea to confirm that the fluid level is correct. Just because it was serviced does not mean that the mechanic filled the transmission properly. Most mechanics "guess" at what the level should be and do not actually go out and drive the coach long enough to get the transmission fluid hot enough to properly check the fluid level. Fluid must be checked with the engine running in PARK, after the transmission has reached normal operating temperature.

[ArchHoagland]

williamp321 wrote:
Arch now u know the years and the miles cant you tell me any info now.

It's important to know the all the information as tomousecap's repy proved.

On certain years there are problems with certain things and having all the information helps us to provide accurate answers.

For instance, now that I know you have a 2003 I know that it came with Dexron III transmission fluid and not Transynd. That means you should have changed your transmission fluid at the very minimum of twice over the past years along with the spin-on filter.

In any case it looks like the ABS symptom ties in with the problem you have and hopefully your issue will be solved.

[williamp321]

Arch now u know the years and the miles cant you tell me any info now.

[tomousecap]

williamp321 wrote:
Bob u hit the nail on the head My Abs lite on the dash came on and its erratic also. Taking it in the shop tomorrow to put a computer on it to fine out about the abs lite Thanks.

I expect that it could even be the brake caliper problems causing it if you haven't had the brake calipers all replaced per the Workhorse recall. These darn vehicles now days have everything tied together by networked controllers. Good luck fixing them yourself anymore.... 🙂

Hope you get it figured out.... 🙂

[williamp321]

Bob u hit the nail on the head My Abs lite on the dash came on and its erratic also. Taking it in the shop tomorrow to put a computer on it to fine out about the abs lite Thanks.

[williamp321]

Its a 2003 Georgetown 35 foot 8.1 Allison workhorse . No I don't use the speed control in the hills. 52,000 miles

[tomousecap]

I am going to worry you a little here, but we had that same exact symptom on ours early in life. The 1000 was going in and out of torque converter lockup allowing the RPM to vary around 300 RPM up and then back down. The cause was not a bad transmission or overdrive cycling. The cause was that the ABS brake system was throwing error codes right and left. When we finally got to a service place that would work on it, it was found that the right rear wheel bearings were going bad and the right rear wheel was moving in and out confusing the ABS sensors causing ABS error codes. The trans was getting messages to drop the torq converter lockup from the ABS system... Upon teardown the rear axle was discovered to have the wrong outer bearing cone in it from the factory and it was on the verge of allowing the wheel and axle to come out while rolling.... shiver, shiver... Would have been pretty messy had that occurred while moving. Fixing the rear axle corrected all the symptoms in the trans and all was well.

Long story short is that be aware that the ABS system can cause trans controller corruption/errors because it is trying to compensate for a problem... 🙂

Good Luck with your problem.

I might add that the right rear wheel oil seal was also dumping oil on the inside of the wheel where it didn't show outside easily. I was told when this happened that there were a number of the axles made with the same wrong bearing around May 2006 when our chassis was built. They also use the same axle on some of the Fords.

[ArchHoagland]

What year and how many miles?

[rvten]

Are you running hills in cruise control?
This will cause a lot of unneeded down sifting.
As other have posted. Need to keep above 55.
I miss my Allison trans.

[williamp321]

I just service it and it still does it. I keep it between 60 and 70 and it does it more then. I will put some miles on it this week end since I service it I done a road test of 10 or so miles and it was still doing it. will report on it after I put some miles on it this week end.

[othertonka]

I believe what you are experiencing is it is going in and out of Overdrive. Either turn overdrive off until you can reach a speed that will keep it in Overdrive, which is around 55 with a steady throttle. If you get it in OD and then you allow it to drop the speed below 55 it will usually downshift and drop out of Overdrive. This practice is not good for the tranny and tranny fluid can heat up. So when this happens either speed up or turn the overdrive OFF.
PS. I have the 1000 tranny and this is what I do.

[wa8yxm]

Yup, turn off overdrive when it does that.. This can happen if you are towing and hit just the right combo of grade and weight and headwind and such.

Also, the suggestion of routine service is a good one.

[rgatijnet1]

Going in and out of overdrive?
How many miles since the last fluid change. Transynd or Dex III?