Community Forums

RKins · 09-08-2018, 06:01 AM

When I replaced mine I was told the sensors are the same for the engine speed and the transmission output speed (at opposite ends of the tranny) - one uses a 90 and one uses a straight but both can work in either place. Take a 13mm socket and maybe a small flat screwdriver to pry a little.

Mr_D · 09-08-2018, 09:22 AM

The sensors are the same other than the 90° one lays closer to the case. Depends on how they ran the wires and if they left enough slack.

ftodaro · 09-08-2018, 03:12 PM

Allisonman: I have a 2002 XC Chassis with a 3000MH trans and Cat 330. bought the coach with 33,000 miles on it, it now has 47,500.00.

When my Trans gets warm i have an occasional flair when it is up shifting from 4 to 5.

Its intermittent, but always when its hot. It is not throwing an code. the fluid level is good. the fluid it good converted to Transind last year.

I just took a 2000 trip and it was flawless since i was in High gear 99% of the time.

Is this anything I should worry about?

ftodaro · 09-09-2018, 05:17 AM

Quote:

Originally Posted by ftodaro

Allisonman: I have a 2002 XC Chassis with a 3000MH trans and Cat 330. bought the coach with 33,000 miles on it, it now has 47,500.00.

When my Trans gets warm i have an occasional flair when it is up shifting from 4 to 5.

Its intermittent, but always when its hot. It is not throwing an code. the fluid level is good. the fluid it good converted to Transind last year.

I just took a 2000 trip and it was flawless since i was in High gear 99% of the time.

Is this anything I should worry about?

oops that should be 2001 not 02

hardy1000 · 09-09-2018, 05:21 AM

Thank you looking forward to your posts.

gemert · 09-09-2018, 11:34 AM

Quote:

Originally Posted by Allisonman

Hello gmert,
I also do not think there is any issue with the transmission because if you reach 230f it will throw a code to you for overheat. Also if you are running that hot, your engine would be running hot also because it uses the same coolant going thru the transmission cooler as the engine.
I would look to see if the wire between the sender and the gauge is shorted to ground somewhere. Also the sender or gauge could be defective.
The test I do for that is disconnect the wire at the sender (down at the transmission) and short it to ground. If your gauge pegs all the way to the right, your gauge is good and you need to replace the sender. If the needle doesn't peg, then the gauge is usually faulty. Thank you for the question and have a great day

Allisonman, Thank you. The temp routinely goes above 230 without any indicator lights showing on the dash. I have checked the temp of the sump area before when it was running hot. The actual temp (with IR heat gun) reads the same as the gauge. The engine temp never follows it high. The hottest I've seen engine temp is 196 going up steep grade. Thanks again.

Rsponsford · 09-09-2018, 01:35 PM

Quote:

Originally Posted by dbarton291

The four speed Allison cannot be reprogrammed like the six speeds. There are things that can be done to help them. You need to tell us exactly which model you have. The model designation is on the name plate which is on the side of the main case.

Following. Our 1990 Concept has the Allison HT 747(D) transmission.

Allisonman · 09-10-2018, 03:08 PM

Well sorry to say I do not think it is the Allison system. I think when they repaired your lifts that a wire may be pinched in the system and shorting out? Please let me know if they find anything.
Have a great day! :0

Allisonman · 09-10-2018, 03:13 PM

Hello,
These are not electronic transmissions unless it is ATEC. It could be a couple things. 1. The modulator might not be adjusted correctly. Most in that year have an Air Modulator and it could be getting worn out. The modulator modulates shifts higher upshifts and lower downshifts. If it is not working correctly, you will have full modulation even when off throttle and your downshift will be too high.
2. you can have the trimmer springs softened up in the valve body by an Allison distributor or dealer. Either is not too big of a job.(I say that with 40 yrs experience, I'm sure it isn't that easy LOL)
Hopefully they can smooth out your shifts for you.
Have a great day!

Allisonman · 09-10-2018, 03:17 PM

Wasn't that an electronic pushbutton shifter trans? If it is, the relay it is showing should say Allison TCM instead of engine. Being wired thru the transmission, you can choose which gear you want the transmission to shift down when the exhaust brake is on. Otherwise it will stay in 6th and that is overdrive which will not slow you down as well.
Thank you and hope all goes well!

Allisonman · 09-10-2018, 03:22 PM

I would check and see if any codes are present using your shift tower. Press both arrows at the same time. If you press once, press again and it should say D1-- if it doesn't and says for example D12216 that would be a code 22-16. If you have no codes and are still worried, stop by an Allison distributor or dealer and have them do a Transhealth test with their DOC software. This will tell you the condition of your clutch plates. some charge a fee for this, but we do not. Let me know if you have any codes. Thank you and have a great day!

Allisonman · 09-10-2018, 03:28 PM

That surprises me about the temp matching the gauge. Were you checking the cooler return line or the to cooler line which would be the hottest oil out of the transmission. Did you see if you are getting a code for high temp? Allison will throw a code at 232f?
I'm also surprised the engine temp is not rising any. Do you have a retarder on your transmission that may be causing the heat?

Rsponsford · 09-10-2018, 04:40 PM

Quote:

Originally Posted by Allisonman

Hello,

These are not electronic transmissions unless it is ATEC. It could be a couple things. 1. The modulator might not be adjusted correctly. Most in that year have an Air Modulator and it could be getting worn out. The modulator modulates shifts higher upshifts and lower downshifts. If it is not working correctly, you will have full modulation even when off throttle and your downshift will be too high.

2. you can have the trimmer springs softened up in the valve body by an Allison distributor or dealer. Either is not too big of a job.(I say that with 40 yrs experience, I'm sure it isn't that easy LOL)

Hopefully they can smooth out your shifts for you.

Have a great day!

Thank you. Now to find an Allison tech in my Northern Bay Area!

hunterstuart · 09-10-2018, 05:24 PM

Quote:

Originally Posted by Allisonman

I have been strictly an Allison Tec, manager, Allison rep and now outside sales for 40 years. I used to answer questions before about 15 years ago but became quite busy in my job and lost track.
I have come here to try and lend my expertise to RV owners who have questions about their Allison Transmissions. I really enjoy helping out so please if you are having an issue with your Allison, please leave me a question. I try and check in every other day so please be patient. Thank you and "Have a great day!"

From hot Arizona, my 2009 GMC Sierra 2500HD overheats fairly quickly when towing my heavy 5th wheel uphill. Need I pay attention to the Allison transmission as part of the solution??