I changed the oil on my transmission, it had about 40,000 kms on it. It had worked pretty hard pulling my 5th wheel. It was a good color yet and didn't smell burnt. Put new filter on it as well.

Now shifting from 2-3 the rpm's come up and it shifts quite hard. Also from park to reverse is about a 2 second pause and from reverse to drive about 2-3 seconds before it engages.

I put a new NSBU on last year, I hope it's not that again, it would be my 5th one on this truck.

Any Idea's about what happened.

Thanks in advance.

Check your fluid level, allisons can be real picky if the fluid level is'nt correct. Should be in the cross hatch on the dipstick when up to full operating temp.

Check your fluid level, allisons can be real picky if the fluid level is'nt correct. Should be in the cross hatch on the dipstick when up to full operating temp.

Good point. Common mistake to fill the trans to "full" with the engine off. With it not circ'ing through the cooler, that will be a quart or more low.

Level must be checked whilest said engine is running.

Put it in the middle of the "HOT" when idling in park with the trans warmed to 80C/175F.

The oil level is bang on when hot. It seems to be shifting better as I drive it more until I put it into tow/haul, that it shifts hard and bangs between shifts.

Could it be that the brain needs to relearn again with new fluid in it? Could the new fluid reveal a bigger problem that I've cooked my tranny? Could the internal filter need changing to make it do something like this?

My shift indicator is still on so I'm convinced it's not the NSBU.

Before you know you are going to be driving it for awhile - and also the normal way that you drive it - take your HyperTech programmer and reset the trans-learn.

See if it smooths out after some miles.

It is starting to shift better already after a week of driving.

One thing I didn't think of was that I went back to my summer tires at the same time I changed oil. They are a little smaller than my Blizzaks and maybe the combination of fresh oil and tire size was enough to make the computer freak out a little bit.

The tranny oil smells fine and temp gauge is good, so I'll keep on driving it, I guess.

Thanks for the input all!!

This is one of the best places to get good advice on the web!!!

This happened to me too when I changed to Torque Drive synthetic fluid. I pulled my 7k travel trailer right after changing the fluid. I thought something was wrong the way that it shifted. Tow/haul mode was really bad so I put it in regular mode and it acted a little better. After about a week it seemed to straighten out. It seems like the trans has to "re-learn" how to shift with the new fluid.

did you use a allison filter or another brand?

What kind of fluid did you use?

I used and OEM filter and the oil was Petro Canada's Dextron ?, not sure which number but they said it was the right one. we have a 45 gallon drum of it for all our trucks, 7 Dmax's. None of them have had any issues using the oil.

As I've thinking about this there may be more to the story than I first thought. I had changed the oil and tires and then on the way home, I had an idler pulley sieze on the engine. I put the truck's transfer case into nuetral, and towed it back to the shop. I also put the tranny into neutral, the manuel says to tow it in Park. I only had to tow it 4 miles and we towed it at about 15 miles an hour.

I talked to our dealer's service manager, great guy and honest, he said that I should reset the computer on the tranny as the tow may have messed with it.

The saga continues. The tranny shifts slow under light throttle. Under heavy acceleration, the engine defuels, and takes a second to shift to 3rd gear and bangs hard when it shifts. So I'm not pushing the truck obviously until I can get the tranny reset.

I'm going next week to get that done.

Also, I took my programmer out to see if it had anything to do with this. It still shifts the same. So tried to put it back in now I get an error code that won't let me reinstall the programer, big sigh of frustration.

What do you guys think?

Sound like you need your ECM and TCM reflashed.

Well the saga continues. I flased both the ECM and TCM and it seemed to work well for about 12 hours, then it was worse than ever. The shift from 2nd to 3rd would slip real bad and 4th to 5th would slip as well. The tranny fluid was smelling burnt now as well. So I guess I cooked my tranny :(.

Time for an upgrade :). Now have the Heavey Hauler Race tranny in and I love it. My tranny was bad for a while compared to how firm this baby shifts. Now I'm not afraid to add more power toys to this thing :D.

That's the way things go I guess.

Thanks for all the input!

How many miles did you get out of it?

It only had 180,000 kms on it before it packed it in. It must have been going for a while though. The truck always had a little hesitation and a flutter (don't know how else to explain it) when you would accelerate, not even hard acceleration, just light acceleration and it would shake back and forth like it wanted to go, but just couldn't. That's all gone now with the new tranny.

Loving the new tranny more each day, it rocks! :D