Tell me if this sounds like it's shifting right

[WILD-BILL]

First off, it's a 94 Winnebago W/ a 230hp Cummins and a 6 spd Allison. Not sure exactly what the #'s are on the trans though it does have the push button pad for shifting.

Now, a little history.....

Ever since I first bought it (used) about 7 yrs ago it has had a very hard down shift from 2nd into 1st gear. Other than that, it upshifted and down shifted fine and would kick down a gear when you out your foot into it. However, I never noticed a difference (either while towing or without the trailer) in the Economy mode.

About 2 yrs ago I lost the kick down feature. After some research I replaced the throttle position sensor and still had no kick down. During this time, the rig seemed to be down on power as well.

Fast forward to about a month ago. I took the MH to the local Allison service center and they showed me how to read the codes and determined that the TPS was failing the low side counts. I adjusted the cable mount as instructed and it seems to have fixed ALL my issues yet raised a new concern.

While it no longer has the hard down shift and I am able to step on the gas and have it kick down it seems I have lost all my engine breaking during deceleration that I used to have.

Prior to the repair I could be traveling at speed and either coasting or on the brakes the trans would down shift and help slow the rig down.

Now, I can be doing 60 mph and get on the brakes approaching a 35 mph zone ahead and it will stay in 5th gear till I'm way down (say maybe 20ish mph) or step on the gas and it will downshift (rather quickly but not hard) down to 3rd and then go.

My father has basically the same MH and running that mine has and it seems that this is the way his has always been.

Does this sound right to anyone?

Should the coach have some engine braking while decelerating?

Oh, and no. It does not have an exhaust brake

[Mekanic]

It sounds like you may have adjusted it just a bit too far. Sometimes on these TPS sensors it is hard to find the just the right balance point.

[WILD-BILL]

So, I should have some engine braking when decelerating even without an exhaust brake?


FWIW, it's not throwing any codes now. Either high side or low side counts.

[WILD-BILL]

Quote:

Originally Posted by Mekanic It sounds like you may have adjusted it just a bit too far. Sometimes on these TPS sensors it is hard to find the just the right balance point.

You may be on to something. While I have yet to adjust anything I I did drive the rig W/ the trailer down the same road to the track I've always used so now I know I need some kind of adjustment. There is one ill that even in Cruise Control that it would down shift to 4th just before cresting the hill. This time it only went to 5th and never down shifted after that like it used to so it looks like I have to tweak it till I find that sweet spot.

Thanks

[WILD-BILL]

Well, I adjusted it down as far as I could with out resetting the low side count code and will see how it performs on this weekends trip.

[WILD-BILL]

Well, now I'm not sure what to make of it.

After adjusting the cable down as far as it would go without resetting the code it did, on some occasions shift down into 4th gear going up some of the hills it used to but not some others. There has been no change however in down shifting during deceleration.

That said, My parents have an almost identicle MH with the same drive train and as near as I can tell both are down shifting the same on deceleration.

I'm hoping the trans down shifting issue when I'm trying to go up a hill is nothing more than the trans trying to releanr after being without the TPS for so long.

I guess time will tell.

[allisontec]

You may need to take it to a Distributer,have them check the TPS counts,I prefer around 60 counts,also reset TPS %.You probably won't feel much hold back until 4th range(1:1) 5th and 6th are Overdrives.It wouldn't hurt to have them reflash the ecu to the latest calibration.

[WILD-BILL]

I asked them about a reflash and they said there weren't any and no more updates due to the age of the trans.


Any way I can check the counts myself?


I do feel some hold back once it goes down to 4th but I think (and it used to) shift down sooner. Sometimes it doesn't reach 4th until I'm below 35mph.

Also, while in cruise control and going up a hill, sometimes it will do really well downshifting and maintaining the speed even going into 4th and holding the speed, and other times, on a longer/steeper hill it will only downshift to 5th and lose almost 10mph.

[allisontec]

True,there may not be any recent updates,but if yours still has the original cal(version 7)then it wouldn't hurt to reflash.It will update itself to the latest cal available.Something else to consider is engine power will cause a lot of shift concerns.Make sure your not running a little low on power.