Is allison 6-speed shift timing adjustable?

[sdlcrazier]

I am new here and this is my first post. I searched the forum but unable to find the answer so please pardon me if this question is a duplicate...

I am about to purchase a 98 Country Coach Intrigue, everything appears to be fair except the transmission being kinda gittery - I can feel the gear shift from 1st to 2nd and from 2nd to 3rd is short and abrupt. I am not sure if Allison transmission is using vacuum which is leaking/low, or a bowden cable which is due to be adjusted, or if this indicates a potential internal failure. Appreciate it if somebody have such experience and share your thoughts...

Steve in SoCal

[Rook]

Steve.....could be something simple.....but probably not! It will be a good use of your time and $$ to get permission of the owner to allow you to drive the coach to a qualified Allison Transmission Service place and let them check it out. Might save you a very bad and expensive purchase decision. Rook

[RickO]

Welcome to the forum! Good advice from Rook IMO.

Good luck...

Rick

[sdlcrazier]

Thank you Rook and Rick. Yeah I forgot the pro inspection part, it will be well worth the money. I'll search if Allison authorized shops are nearby.

[Grimesy]

I don't have the info handy but in the past I have contacted Allison, spoke with a tech and felt comfortable with their responses.
Don

[sdlcrazier]

Thanks Don. Checked Allison service centers, the closest is about 30 miles away from the rig location.

[336muffin]

Steve, welcome to the forum. I have to ask are you pressing the mode button to drive it or not. What is the ambient temperature when test driving? And don't take offense, but have you driven motor homes with Allison's before? Mine drives a little different when cool and takes a while to "warm up" and start shifting smoothly. If not pressing the mode button, this will make the Allison feel odd if not accustomed to driving one. Give a little more info please on previous experience.

[sdlcrazier]

Quote:

Originally Posted by 336muffin Steve, welcome to the forum. I have to ask are you pressing the mode button to drive it or not. What is the ambient temperature when test driving? And don't take offense, but have you driven motor homes with Allison's before? Mine drives a little different when cool and takes a while to "warm up" and start shifting smoothly. If not pressing the mode button, this will make the Allison feel odd if not accustomed to driving one. Give a little more info please on previous experience.

I had test-driven CC rigs before and test-drove this one that I was interested. The ambient temperature was about 60f and engine was in normal operating range. When felt the jittering, I tried in mode 4 and then in 6 (6 is full gears), the results were the same. Reverse was smooth. Asked the seller who sit with me he said it had been like that since new.

The rig has about 62kmi and one-owner. I am thinking if the seller was telling truth, there might be adjustments somewhere due. (I have been driving diesel cars for 20+ years and fixed vacuum and adjusted kickdown cables to make those shifting smoothly. I am not sure Allison has those components).

[Skip426]

Steve, as 336Muffin, has stated the 6spd Allison shifts are temp sensitive, and if the 98, in question is similar to my 99(3060), then all inputs are electronic, and there is a marked improvement of shift quality when full operating temp, is achived. Has the current owner given any indication of trans service/repair, if so was the servicing done recently enough to be an upgrade to synthetic trans fluid ? Synthetic fluid is now the Allison rec-commended change up in fluid, and I'm not sure how many years ago that started; other posters will probably have the date.

[sdlcrazier]

Thanks Skip and 336muffin. The seller was a small business owner, the rig registration was on his name since 98. Funny thing is - there were no service records prior to 2010, he said during that period all services were done in his company so no receipts! He did show me two recent receipts (last year), but all were for minors like sensors or vents etc, none of them were related to transmission (surprised to me that he didn't know what chassis was "DynoMax"). I did check tranny fluid, it was fresh, so was engine oil. Lots of mystery

[wa8yxm]

Is it possible to change the shift points.. YES, How to do it, Well, I have two answers.

1: No clue
2: Brazill's RV (At least I think I spelled it close) They do know how to do it. and that is about all I can say.. Oh, Redlands RV can do it too.

[sdlcrazier]

Quote:

Originally Posted by wa8yxm Is it possible to change the shift points.. YES, How to do it, Well, I have two answers. 1: No clue 2: Brazill's RV (At least I think I spelled it close) They do know how to do it. and that is about all I can say.. Oh, Redlands RV can do it too.

Next time when I drive to Brazill I'll have them do it for me :
(Where is Redland RV btw?)

[Steve Ownby]

Steve,

These electronic Allisons utilize "learning" programing. If the chassis batteries have been completely disconnected lately than the transmission would have lost its adaptive programing and it takes several learning cycles to settle down.

Buying a '98 model with no service records is a gamble. The future longevity of the drive train in particular is a direct result of the care it has received. Press him a little bit for service specifics. The transmission fluid should have been changed several times. Has he switched to Transynd fluid? If he continues to be vague and you are really interested then I would ask for both Allison & the engine manufacturer ( probably Cat) to run diagnostics and test a sample of both fluids. Look at the birth date of the tires also. Cheap insurance. Hopefully it will all check out because those Country Coaches were great coaches.

Good luck & safe travels.

[Gary RVRoamer]

Shift points are controlled electronically and the only way to change is to reprogram the computer module. There is, however, adaptive logic in the module that tries to tune itself to the operators driving style. If you have a heavy foot and the owner had a really light touch (or vice versa), you could notice differences in how it responds.

If any doubt at all, get it to an Allison shop for a check-out as a pre-condition of the sale.