Allison SLAMS while in gear

[Riverholic]

I just recently lifted my truck and put 37" tires on it. My question is if I am in level 4 of the hot juice occasionly I will get a huge SLAM in 2nd gear. It is not when it is shifting, it is about half way thru the rpm's and then all of a sudden 'the SLAM'. I have since set the juice up for levels 1 & 2 and it doesn't do it. I am going to regear my truck to the 4.10's when money allows but do you think that the gearing has anything to do with 'the SLAM' or is it something with the Allison?

[a64pilot]

Methinks it's something with the ally induced by the Juice. IMHO pick a level, any level and leave it alone for a couple of hundred miles or so and see if the erratic behavior goes away.

[RVGuy]

Riverholic,

I'm having the same thing happen. Although, in my case its in T/H, level 2 while towing my 5er.

It really hits hard. I've got to where I can react to it quickly and reduce the slamming to an extent.

I just wish it would go away all together. Next time I tow, I'm going to remove the Juice and see if it happens without it.

Then, put it back and try different levels, etc.

If you come across anything on this, please post it here and I'll do the same.

[Billy14]

Hey guys,

I've posted on this topic several times without receiving any solutions. I pull a 16,000 lb. dozer occasionaly in T/H level 2 & thrown coffee against the back seat with the cup in the console. Scary, but haven't had to use the dozer to round up parts on the hwy. YET! Happens from 2nd - 3rd and sometimes 3rd - 4th.

Edge told me to drive easy for an hr. or so with no load. This did work but only for say maybe 6 -10 shifts then it started slamming again.

I run level 4 in regular. If I hit it after the Allison shifts into 2nd, it will slam into 3rd almost every time with 60 - 100% throttle applied. Don't know what to do but it seems eventually something has to break.

On Edit: RV Guy is right. If you anticipate the next shift and back off the throttle its not as bad but, when pulling up a grade the tranny shifts so fast it gets pretty tough control.

Billy

[ 06-14-2003, 12:08 PM: Message edited by: Billy14 ]

[ACCRASH]

I have also noticed the hard shift fron 2nd to 3rd. It really hits hard. Thankfully, it doesn't happen all the time. Just wish I knew the cause. Maybe someone with some insight can help us out here. :(

[Billy14]

To all,

A few of the guys have enlightened me to what appears to be a matter of impatients on my part & maybe yours.

See Duramax 6600 & topic Hot Juice L4 - Too Much Fun

It appears that if you start up with the Hot in the lower settings & work up to L4 the Allison will perform as it should without the hard shifts.

I will wait for a few more answers to my last post which you should probably monitor.

Billy

[Waypoint3D]

All the talk about a slam shift 2nd-3rd got me curious this weekend. So I went about trying to reproduce it.

I was able to make it happen no load, under these conditions. First , everthing was done t/h, I dropped my level from L4 to L3, then right about the 2nd-3rd shift point I would hesitiate or slighlty back off the throttle and get back into it very easy. Sure enough...bang..hard shift. The second way was accelerate slowly and just before the 2-3 shift, accelerate hard....bang..hard shift.

So I don't no if we can class it as a problem or just one of those things you get when you modify from stock. I'm sure it has to do with a combo of added power levels, tire size, loading, varied driving styles and the Allison 1000 trying to figure out what to do.

Sooo... I'm going back to L4 t/h and drive it ...

Jim http://smilies.networkessence.net/s/contrib/edoom/theyareontome.gif

[RVGuy]

While I do appreciate the fact that others have experienced this and/or have been able to "make" it happen while doing certain things, etc. I can assure you this is not a natural act being performed by the tranny. Nor is it an act that is being induced by certain driving habits.

Unless you call mildly accelerating from a dead stop to cruising speed, while towing a 5th wheel in T/H mode as anything other than normal driving habits. We're talking constant pressure on the go pedal, producing about 15 psi of boost while shifting up through the gears. Then...all of a sudden, slam!! Doesn't do it everytime. In my case, I would say it does it 20% of the time while towing.

And while I understand the Juice (Hot in my case) may have a learning period while it does its thing with the Ally trans, this type of shift should not be apart of its shifting patterns under any circumstances..learning or otherwise.

Oh, by the way, I tow in Level 2, T/H mode.

[ 06-16-2003, 04:48 PM: Message edited by: RVGuy ]

[Billy14]

Waypoint,

What you described is the exact technique needed to produce the slam shifting in my truck as well.

Billy

[Waypoint3D]

RVGuy....you're correct...what I mean't to say was in my case I have to change driving patterns to reproduce it. So until I tried to make it happen I hadn't experienced it. However, that does not diminish the fact it is a real problem, especially if towing.

Do we know if any of the other performance boxes cause the slam shift?

If it's a Juice only issue, the more details we give the Edge guys, the better.

[Billy T]

Guys,

My 02 was doing he same thing in T/H with or without juice. I never tried to learn how to make it slam, but every now and then while towing our fiver, slam on 2-3 shift. Told my dealer about it, they reflashed it and it has not done it since.

Good Luck

Billy T

[RVGuy]

Billy T,

This is good news. You are the first person that has said that your Ally slams without the Juice.

I'm making an appointment with the stealer tomorrow.

I'll post the results as I will be pulling the 5er this weekend.

[mackin]

Originally posted by RVGuy:
Billy T,

This is good news. You are the first person that has said that your Ally slams without the Juice.

I'm making an appointment with the stealer tomorrow.

I'll post the results as I will be pulling the 5er this weekend.

Slam in second gear while in
T/H with juice turned up. Lockup engages in second gear
and most likely is the cause for the slam. Flow reverses in the converter
from converter to lockup mode and I wonder if we have a timing issue.

Done deal my friend ..... ;)

Don't ask !!!!

Mac :D :D :D

[RVGuy]

OK!!

Where did the quote come from???

And what was the solution to the ally "timing" problem?

[Kennedy]

When you take a fully adaptable, electronically controlled transmission, add a bunch of HP to an engine with a power box varying over a wide APP range,add varying load conditions, it's hard to be prefect...


pun intended ;)

[blakmax]

Gents, I rebuild Allison World Transmissions and this shift problem sounds so similar to the bigger Allisons.My truck included.The TCM commands shifts and is a watch dog that measures shift timing, i.e how long a shift time happened!If the transmission slipps or hits hard the tcu can adjust it.Makes me think the tcm is losing its memory. I'll post ya when i get out of Allison school in September.How embarassing,I have rebuilt Allisons since 1976, My new software is forcing me back to class!My truck will put your coffee to the back of your throat when it is shifting to second for two upshifts when cold.

[mackin]

Originally posted by kennedy:
When you take a fully adaptable, electronically controlled transmission, add a bunch of HP to an engine with a power box varying over a wide APP range,add varying load conditions, it's hard to be prefect...


pun intended ;) That is an understatement ..... Get ready to be indulged with Q's.... My APP is so tight,not much ankle exercise needed ....
;)

Mac :D :D :D

[ 06-19-2003, 04:49 AM: Message edited by: mackin ]

[Dave K.]

Same Problem, no juice.

My 2001 Duramax /Allison does the same thing and it is completely stock. This hard erratic shift problem just started a month ago and I had the truck in the shop twice. It will slam into second gear hard enough to throw a can of coke from the holder, rev-up between gears and as well downshift hard with a bump just before stopping.

The dealership cannot find any codes that show a problem. They did a recent update to the computer as of 6/06/03 to remedy shift problems and "help" the trans learn ones driving habits. Well it worked ok for a couple of weeks but now it is doing the same thing as before. The dealership stated that they are "researching the problem" but without the codes there is nothing they can do for now.

If anyone finds something out, please let me know.

Dave K.
E-mail: Baysiders@aol.com