Allison Transmission Questions

[chevy81allison]

Allison Transmission Questions

Dear AllisonMan,
I have 35" tires on my chevy 2500HD and cannot find any info on how to correctly recalibrate my speedo and TCM. Am I stuck with regearing my truck?

 

[AllisonMan]

Allison Transmission Questions

Hey chevy,

Sorry to say there are no calibrations except what comes with the truck. Besides your speedometer calibration being off, this also throws off output speed to your transmission computer (TCM). At the last Allison regional meeting I went to, even though an Allison dealer cannot touch an LCT in a pickup until the warranty runs out unless it a service, they were very convincing to NOT put any bigger tires on your pick-up. It has a VERY high potential to ruin the transmission. I am sorry the dealer did not tell you this when you bought the truck.What it does is throw off the calculated output speed, making the transmission shift at the wrong time and torque time. I still hope you have a Great Day! (I sure wish there was a new calibration. Our president of my company really wants them too)

 

[AllisonMan]

Allison Transmission Questions

Hi again william,
Sorry I have not had a chance to look up this CIN. It is correct the older WTEC II started with 0800.(My service writer is on vacation and man I'm busy LOL) I will try for Friday if not Monday for sure. Thank you and have a great day!

 

[AllisonMan]

Allison Transmission Questions

Hi Bruno,
The different ratings are because in the calibrations, they cut back torque in the calibrations. This is why an MD3000MH can handle 400 hsp. Thanks Bruno and have a great day!

 

[AllisonMan]

Allison Transmission Questions

Hi Hancock,
Sorry to say we are not up on the Kingcruise system. The only thing I can tell you is that I have gone on a few service calls where the Kingcruise is the problem. Did you get a book or number to call for Kingcruise? They were very helpful when I called. They took me through the troubleshooting procedures step by step. On the other hand, we would love for you to come to our facility even if we do not do the service on your motorhome. I think you will be impressed with us here at Pacific DDA in Ridgefield, WA. Thanks and have a great day!

 

[chevy81allison]

Allison Transmission Questions

Thank you AllisonMan. At this point the tires are on and I will not be changing them. Currently shifts seem to be fine. I should probably watch the tranny temp though huh? I am currently talking to a company that says they can adjust the parameters for my 35"'s but we shall see. If I don't care about a void warranty, can someone do the recalibration for me? Also, wouldn't regearing to an equivilant ratio solve my problem?
Thank you,
chevy81allison

 

[AllisonMan]

Allison Transmission Questions

Hello Mr. Phelps,
Here is what your ECU is calibrated for.
6 speed
shifts @ 2500 rpm (meaning your engine must turn at least 2650 for this calibration to work)
Set up for TPS not for an electronic engine
and this calibration is out odf a utility truck or refuse.
It is setup for exhaust brakes if you need.Preselect is set for 2.
Hopefully this is the info you needed. Thanks and have a great day!

 

[AllisonMan]

Allison Transmission Questions

Hi Chevy,
Let me know what you come up with. As for recalibrating, I would have to request one from Allison and they do not let us touch pickup trucks unless warranty is out. Also as far as I know, there are no calibrations yet, but I would hope someones working on it because I'm sure there a a bunch of people who would love to put big tires on their rigs. Thanks and have a great day!

 

[chzgil]

Allison Transmission Questions

Allisonman
My freightliner dealer told me their was no reason to change the main filter at 6,000 miles just wait until I am ready for a fluid and filter change. He says Allison can give no reason for the filter change and he feels it's unnecessary.
What do you think ??
Thanks
Charles

 

[AllisonMan]

Allison Transmission Questions

Hi chzgil,
Wow, please dont believe what the Freightliner dealer told you. The reason for the filter change is when this transmission is assembled, of course debris from installing snaprings, debris from freshly made hoses (rubber), and what about the cooler? This is the reasoning behind the 5,000 mile service (filter change only). Also Allison requires it to maintain your warranty, so I would try another Allison dealer or better yet, the local distributor for your area.Thanks for the question and have a great day!

 

[RobtS]

Allison Transmission Questions






Allison man---My coach runs and shifts normally until I am on the road for 30-90 minutes. Then it starts downshifting from overdrive to 4th and back up to O.D. very erratically. My only solution was to lock it out of overdrive by using the switch on the dash. So far the only answer is "to bring it in" but no-one really seems to have a clue.

Ever since new, this transmission, usually doesn't shift up to O.D. until I lift my foot from the throttle around 55-60mph. On one ocassion, I experienced the clunking and shuddering noise while putting it in reverse---but that only happened once and has never re-occurred.

Could this possibly be a heat related issue?

Thanks for any suggestions

PS---sorry for the double post

 

[AllisonMan]

Allison Transmission Questions

Hi Robt,
I would be more concerned that it is an engine problem. It may have a loss of power and when it makes the shift when warm, you lose rpm causing the transmission to shift back and forth. One way to tell if you have an engine problem or a transmission problem is a stall test. With the transmission in neutral, see what your engine no load rpm is (just push throttle to floor and engine has a govenor and will stop rpm at certain point. CAUTION DO NOT DO IF GAS ENGINE DIESEL ONLY!)Next put transmission in drive with parking brake set and foot on brake. Step on the throttle again and see when rpms stop (ONLY DO THIS NO MORE THAN 4 OR 5 SECONDS AFTER RPM STOPS) ideally stall rpm should be approx 4-500 rpm lower than no load rpm. For example, if your no load is 2600rpm and your stall rpm is 2100-2200 this is good. If stall is lower than that for example no load 2600 and stall 1800rpm, then more likely to be an engine problem. If your no load is 2600 and your stall is 2400 then Id be pointing to transmission. If everything in the stall test look ok, please write back and I'll see what else may cause this.
Is this a worhorse chassis? If it is, look under the coach on the right side of your engine. I have noticed battery cables melting in this area. Please, it is very important that you let me know if this is the problem so ZI can get GM and Workhorse to inform their OEM's. I would also like to know who the OEM (bodybuilder) is. Thank you and have a great day!

 

[RobtS]

Allison Transmission Questions

Allison man---This is a gas Workhorse chassis---8.1Vortec with a Allison 1000 transmission---sorry didn't realize I had omitted all that info.
I crawled under my MH to check the battery cables and they were OK. In fact it looks like a very neat installation --with aluminized tape covering most of the cable to the starter. This unit is a 2002 Holiday Rambler Admiral.

I have an appointment in the A.M. to let Allison take a look---hopefully they'll be able to point me in the right direction.
Thanks for your time---I may be back
Bob

 

[AllisonMan]

Allison Transmission Questions

Hi RobtS,
I appreciate the feedback on the body of your Workhorse chassis. I am glad you did not find any melted wiring. If you are going to an Allison Distributor, they can run on their computer a SCAAN run. They need to take tire size, gear ratio's, etc. and then they can compute road speed that all your shifts should be occuring. Good Luck and have a great day!

 

[RobtS]

Allison Transmission Questions

Allison Man--Well my tranmission has been re-programed according to
18-1K2K-02, Rev.A
July, 2003
Product Code(s).
Page 1 of 2(This is an Allison Rev.)(It still is erratic but supposedly, not as bad.)

Allison says that now the engine needs to be re-programed to mesh with Allisons new program.

I'm in the process of getting GM(Chevy) to re-program the engine computer. Hopefully that will stop the erratic up and down shifts from 4th to 5th and 5th to 4th.

What a pain!!!!

 

[Flynlow]

Allison Transmission Questions

I posted this under General RV but I think I may have it figured out
Good morning Mr. Phelps.
(Remember that from Mission Impossible T.V.)I hope this isn't.
You are providing a valuable and needed service THANKS!!!
I have a 2002 Chev 3/4 with Duramax and allison. At light throttle around cruising speed,the transmission seems to be shifting in and out of gear so fast it is allmost like a chatter (it feels like the engine is missing) so much so that to talk it sounds like we are warbling or talking under water. I took it to the local dealer who checked the "codes" and test drove it and said it was performing as normal. I noticed on one of the web sites that for 2003 they provided a lockout to prevent "hunting". I also noticed that you would only recommend one dealer in the Portland area who was competent with Allison.(my paraphrase). Can you recommend a solution and the dealer to take it to?
Thanks

 

[chevy81allison]

Allison Transmission Questions

AllisonMan,
I am thinking of re-gearing to compensate for 35" tires on my 2500HD 4x4. In theory, re-gearing should trick the stock computer programing into thinking the original smaller tires are still on. I have done the gearing calculations to go from 3.73 to 4.56 and it is very close. The trans output speed should be the same as stock no? Therefore, speedo should be right, shiftpoints should be right.

Is this a good solution?

chevy81allison

 

[Sailorman]

Allison Transmission Questions

Hi Allisonman, Posted this to the wrong section will try again!
Just serviced my '94 MD3060 transmission with filters and Transynd fluid and noticed the new Gold line filter kit (P/N 29540476) has a different number from the original - the new (six inch) filters have a slightly raised rim where it fits on the base plate making the filter slightly longer (overall) than the original standard filters. Also the instructions do not mention the MD3060 at all, but rather, refer to the MD 3000/B. Filters seem to fit just as the old ones did and appear to work fine. The Allison parts man said these filters are the new configuration. Just wondering if possibly the 3000 and the 3060 filters are now interchangable or did they give me the wrong filters?

 

[AllisonMan]

Allison Transmission Questions

Hi RobtS,
Sorry for the slow response, it has been a busy week for me. Has anyone changed the lockup solenoid? It could be working electronically, but mechanically may be sticking? Has anyone hooked up pressure gauges? These problems can be very tricky to resolve. Please keep me posted and I will you if I think of any other checks. Thanks and have a great day!

 

[AllisonMan]

Allison Transmission Questions

Hi Flyinlow,
The dealer may be right that there is no problem. An Allison transmissions whole shift pattern is decided by the drivers position on the throttle. A very light throttle actually is worse than full throttle. What happens is the shifts come at a lower rpm and when it makes the shift, you are not in the correct torque curve and the transmission wants to shift back and forth trying to find the right gear for the rpm and torque. Just try pushing a little farther on the throttle and see if this resolves your shift cycling. If it does not, please let me know, then I need to dig deeper. Thank you and have a great day!