Allison Transmission Questions

Allison Transmission Questions

Allison Man,

I just bought a 1986 Diplomat by Executive (now Monarch). It has a 454 / 400. I noticed that an Allison 4 speed was available as on option and am curious as to whether it would be like an "overdrive" unit or one that gave me more grunt (don't need more..). What model would it have been? The p-30 chassis is an 85, the motorhome an 86. Are they still available? New/used? Expensive? Just curious about what I can do to lower rpm when driving over 55. Vehicle weighs 16000 and as near as I can research has a gross vehicle tow rate of 19000.

Allison Transmission Questions

Hi Cobra54,
I think I understand your question. If you have an 85 or 86 coach, the option would have been the Allison AT545. If you have not replaced your transmission yet, I would say you made the right decision. The combo of Allison AT545 married with a GMC454 was not the best of marriages. Your top gear ratio is 1:1 on the AT545. This transmission does not have a lockup feature like the bigger Allison or even the replacement of the AT, that being the LCT 1000, 2000 or 2400. These are all electronic and do have the lock-up feature which would help with high rpm down the road. Unfortunatly you cannot buy these transmissions yet for re-gearing.So I would say, enjoy the setup you have now, it has been good all these years. Sometimes change can be a big headache. I hope this answers your questions. Thank you and have a great day! :)
Allison Transmission Questions

Thank you AllisonMan. Yea, I'll stay with what I have - I just know, the other grass IS always greener. Appreciate your insight.
Allison Transmission Questions

Hey Allison Man,

I have a 3500 Chevy 4x4 with a duramax and of course the allison tranny. I also have a 2500 with the 8100 Vartec and the allison. The 2500 will really slow you down if you just tap the brake. The tranny cuts in and you'd have to add fuel going down hill to keep going. The 3500 with the duramax doesn't seem to work that way. Do I have a problem?
Allison Transmission Questions

My local Allison dealer told me not to use synthetic (sic) oil, stay wit Dex. III in my 95 MD3060 any comment????
Allison Transmission Questions

Hello Denny,
The one thing that comes to mind is that your engine ECM may be giving a signal to the Allison for an exhaust brake. If it is, the transmission will be fooled thru J1939 communication interface into thinking "you want exhaust brakes" and thru autodetect of your transmission, it downshifts to lower preselected gear everytime you let off the throttle. I hope this is it. Please keep me informed as to what your local GMC dealer finds out. I would contact your local Allison dealer to find out which GMC dealer in the area is best trained to diagnose your Allison. I know around the Portland/Vancouver area, there is only one dealer I would take a pickup to. The others are car dealers and only started working on Allisons 2 years ago which is not enough training.Have you logged on to and looked at pickups "most asked questions?" This may also have an answer. I also have to ask a question, Have you put bigger tires on either truck? If you have, this may be the problem. Not the fault of Allison but GM for only having one calibration for all pickups and if you change tire size, it really messes up shifts and eventually will fail transmission premature. Thanks for the question and have a great day! :)
Allison Transmission Questions

Hi Ken Powell,
I kind of agree with your dealer. If I had a 95 and never had a problem, I ask "Is it worth the expense of transynde?" You may have very low miles, then I would consider it but if you are up around 50,000, I would stick with the dexron III. My reasoning is if you use Dexron, you have to have the fluid changed every 2 years or 18,0000 miles whichever is first. This would give you a chance to have your transmission checked out for any problems. Remember, Allison came out with the World Transmission in 92 so a 95 still has had many updates to it, thus keep driving it the way you have been since you have not had a problem yet but having a 95, I would feel better giving you advise to stick with 2 year Dexron services.Thanks and Have a great day! :)
Allison Transmission Questions

Hi AllisonMan;

Did I understand you to say you folks will do all the required maintenance on motor homes? I have a '91 Dynasty which is due for its 80,000 maintenance. That amounts to just about everything that needs to be done is scheduled to be done bumper to bumper. Can you give me a ball park figure of cost to perform all this work?

Cummins C6AT8.3 with an Allison 5 speed I believe.
Allison Transmission Questions

Hello Allison Man,
I have a 03 Kountry Star, purchased April 2003 have 1300 miles on it at this time! Configured with an Freightliner XC Chassis, 330 Cat 3126E Engine, and 3000MH Allsion transmission!

I read the owners manual and it says to change the 2 filters no matter what fluid at 5,000 miles or 200 hours, Filters are the Main and the Aux/Lube!
I read on the Allison web site that I only have to change One Filter!
What do you think!

Also I have called Newmar, and Allison, and no one can tell me what type of fluid is in the transmission? I do not have a sticker on the tranny dip stick either!

I have not been able to get in touch with Freightliner yet to see if they can solve my mystery!
Since the type of fluid, dictates the future Servicing for the transmission I need to know exactly what I have!
thanks for your thoughts!
03 KS DP
Allison Transmission Questions

Hello ByronK,
Thank you for inquiring about our services here in Ridgefield, WA Pacific Detroit Diesel Allison.
Yes we do service everything under the coach body (engine, Allison transmissions, brakes, etc). The engine is easier to give a price on. For motorhomes we run a special price of $195 which includes oil, filters, fuel filters, 34 point chassis inspection (brakes, leaks, differential, coolant level and condition, etc.)advising you after we inpect if problems are seen. We check air filter and advise if needs replacement.
Without knowing which transmission you have, I will give you prices of an MT643, MT653 at $270.83 and for the bigger HT (I would think you have the MT 643 or 644)is $243.21. We test drive your vehicle and advise on any work if needed. We remove oil and pan, check your trimmer springs, make any adjustments if needed, clean internal screen, assemble, fill with new DexronIII oil, flush cooler and check for leaks. We do have synthetic oil but I would advise Dexron with the amount of milage on your vehicle has done very well with the regular Dexron fluid, this also is way less expensive.
If you have any questions, please give us a call at 1-800-452-0776 and ask for the Allison department. I look forward to meeting you. Thank you and have a great day! :)
Allison Transmission Questions

Hello n8rt,
This is about the most confusing question that comes up time after time. We here at the Ridgefield, WA branch agree with the Allison website and follow their guidlines of only changing the main filter at the first 5,000 miles.
As far as what oil the OEM has installed at the factory, I go by if the dipstick has either a tag for Transynde or at least a red wire tie attached to it (the tags do come off but not the ties)I say it has transynde (synthetic). If there is no tag or red wire tie, I say it is regular Dexron III.
I suggest if you put synthitic in to have a sample done every 2 years. If you stick with the DexronIII you should be good untill 23,000 miles or 2 years whichever comes first.
Thank you and have a great day! :)
Allison Transmission Questions

AllisonMan....I have decided to change my transmission fluid to the new TranSynd. I have purchased a five gallon bucket of TranSynd and the 2 filters necessary to make the change. I have a 2000 Discovery with a Cummins 300 and the MD3060 tranny. Is there a web site where I can find instructions for changing the tranny fluid? I understand that the tranny casing is aluminum and that the filter bolts must be torqued so as not to damage the casing. I need to know what that torque spec is. Thanks.... :laugh:
Allison Transmission Questions

Hi Allison Man. I noticed your invite to Portland Oregon. I live in Vancouver WA. and just purchased a used 1997 Holiday Endeavor with a 6 speed Allison and a 275 Cat on Freightliner chassis.
Being the unit just turned 30k and I have had no contact with the previous owner (bought from a dealer)I feel I should have a service done. Where would you recommend I have it serviced and what do I expect in costs. Thanks for any help to a real novice newbie. Bruno Galliano 360-896-9749 :8ball:
Allison Transmission Questions

Hello bondo3,
If you purchased genuine Allison filters, there are very good instructions inside the filter kit including torque specifications. The only thing it does not cover is how to flush your system to get maximum transyde inside. What you do is after you have done the filter change and added oil, you have two cooler hoses going into the transmission, one either with an arrow pointing into the trans or saying "from cooler. Disconnect this hose and get a 5 gallon bucket. Have someone with the parking brake set and in nuetral, while you are holding the hose, start the vehicle then shut off right away to make sure the vehicle shuts down. Then have them start up again and oil will come out of the hose into the bucket. Watch the oil and you will see it turn from brownish to red. At this point, remove about another 1/2 gallon then yell to "SHUT OFF" so your person starting the vehicle shuts it off. This flushes the Dexron out of both the Torque converter and the cooler which is what you want to do when installing Transynde.
Thank you for the question and if I can help further, please call 1-800-452-0776 and ask for the Allison department. Have a great day! :)
Allison Transmission Questions

Thanks for the info, AllisonMan. I opened the filter kit, and the torque specs were listed in the materials just as you said. Unfortunately, I did not get back to this forum before making the change and I did not get your tips on flushing the system before buttoning everything up a starting her up. Guess I will have to change the tranny fluid again after my next 25,000 miles.....sure was looking forward to that extended interval. One more thing, I noticed some very small particles of shiney metal in the bottom of my drain pan after disposing of the old fluid. Is this normal, or should I have the tranny checked for excessive wear? Thanks for being are doing us and your company a great service....bondo3
Allison Transmission Questions

Hello again bondo3,
No, metal particles are not normal. I usually go with the idea that if it is more than a teaspoon, then have it checked. If this was the first service, it may explain the particles. Was the bucket clean or could it have had previous metal in it? If you were having any internal problems though, I would believe you would have logged a code sometime. Is there excessive slipping in any gear? If you have extended warranty, it would be a good idea to have checked out right away, but if you just had minute particles and the explanation could be maybe this was the first oil change. Allison wants the initial change of the main filter done at 5,000 miles for this reason but I know you are the second owner and it is almost impossible to know. I do not want to scare you, I really do not think you have much to worry about but I have not seen the oil either. Lets hope your bucket may have been contaminated. There is a screen in the valve body module that is a tell-all. It holds almost all of the debris from any internal problem and this project I would not try on your own. My opinion is if it is just a few particles, don't worry but if you thought it was excessive, by all means it is better to have checked out now than when you are on a nice relaxing vacation.
Thank you for the kind words, I love showing all the comments to the president of my company, he can't believe I do this on my own time and is very pleased. I really enjoy it. Please stop in if you are in the Vancouver WA area. Have a great day! :)
Allison Transmission Questions

I'm looking at a 92 diesel pusher with an Allison 5-speed, is this the "World" transmission? The service records are incomplete, and the coach has around 100K miles on it. It seems to run out just fine, but was just curious what a rough estimate on the cost of a rebuild in your area, let's say? How 'bout a replacement? Just wondering what the worst case scenario might be.....

thanks in advance!
Allison Transmission Questions

Did a fluid change this weekend and used the electronic measure on the console. Code flashed ol-95 indicateing sensor failure. Is this item easy to change and could this problem be that I have not run my rig and heateed up the fluid??
Allison Transmission Questions

Hi there lump-dog,
92 was the first year the world transmission came out.Does it have a pushbutton shift tower, a shift selector or does it have a toggle switch? If it is a pushbutton more than likely it is a MD3060 and one this early, Allison will not except for a core so it would be on a time and materials basis. A newer serial number has a wire harness coming out of the case instead of a harness from the chassis attatching with a rectangle connector like the early transmissions have.
You may have an MT654, MT653 which is not common to motorhomes. Are you sure it is a 5 speed or does it make 4 shifts? You might have an MT643 that shifts 4 times but 1 is what we call lockup.
You can tell the model by looking at the tag on the right side of the transmission just above the VB module or pan splitline.
Please give me a call once you have looked at the tag and I can give you our exchange prices. We do have our own factory authorized rebuild facility right here in Vancouver, WA (not our location but very near)called North Trends/ Pacific DDA.My direct number is 360 887-7556 Thanks and have a great day. :)