NAG1 Issues

[JpRngr]

So, I've now got about 100 miles on my car and am trying to work out some bugs. I installed a 6.1L Hemi and NAG1 trans. The transmission was a "good" used part out of an '07ish SRT8. It's acting like it's lost a gear when I step on it(2nd or 3rd), and the engine will bounce off the rev limiter. If I feather it, it seems to shift through all the gears just fine. It doesn't feel like it's slipping, per se, when it actually gets in gear, so, I'm wondering if there's a solenoid or something that might be causing this. Any thoughts?

Corey

[mopar jack]

I think you are feeling the torque management at the max shift point. When I bought my 07 srt I thought I was hitting a rev limit at full throttle shifts from 1st to 2nd but realized it's the programmed shift point to cut power just before it hits 2nd gear. Also unlike an old school car if you use the manual shift function it will automatically up shift to the next gear regardless of the gear selection at the high shift point.

[JpRngr]

I'm not sure about that. It acts like when you miss a gear in a manual transmission. When you let out the clutch and there's nothing there. Then you kinda have to back pedal and try to get it in gear. I have to let off and then it will upshift. Not sure if it's into that gear or the next one.

Corey

[Bullitt-]

I don't know how applicable this is as it involved a couple of late '90s Dodge trucks but here goes.

Had a '98 V6 Dakota that would not go into second, like it jumped out of gear, under moderate to heavy acceleration but did OK under light.  Added some kind of fixit stuff & the problem went away for a while... when it started doing it again I flushed the fluid & replaced with Chrysler spec fluid & new filter... never had the issue again.

On a '99 V6 Ram that had recently been serviced by Express was slipping all the time. Added some friction modifier specifically for Chrysler products & solved the issue. 

Also some issues with an early 90's Caravan that shuddered when it shifted after an Express fluid change... Took to dealer & they changed the fluid... problem solved.

[mopar jack]

Here is a good read on the NAG transmission, a  little long. https://www.lxforums.com/board/transmissions-gears-and-diffs/314488-nag1-5-speed-automatic-transmission-tcm-refresher-info.html

[JpRngr]

Here is a good read on the NAG transmission, a  little long. https://www.lxforums.com/board/transmissions-gears-and-diffs/314488-nag1-5-speed-automatic-transmission-tcm-refresher-info.html

Thanks for the link! From what I gather after reading that, I need to have an adaptation procedure done to it to start with. Will have to see if I can get that done here soon.

[Burdar]

Aren't those transmissions extremely sensitive about fluid level?  Are you sure you have the proper amount of fluid in it?  I thought I remember reading that the fluid level needed to be set with a scan tool.(Didn't read the link yet)

[JpRngr]

Aren't those transmissions extremely sensitive about fluid level?  Are you sure you have the proper amount of fluid in it?  I thought I remember reading that the fluid level needed to be set with a scan tool.(Didn't read the link yet)

The scan tool allows you to get a more accurate temperature of the fluid. There's a table based on trans temp of what the trans fluid level should be. I set the level based on the ambient temp, cause there's a listing on the table for the temp it was when I set it.

[JpRngr]

So, yesterday, was able to get one of shops I deliver to, to do a re-learn on the trans. I think it's better, but still not 100%. Seems to be getting a little better, the more I drive it. So for now, guess I'll just keep putting miles on it and see if it gets better or worse.

Corey

[JpRngr]

So, realized I never followed up on this. I ended up attaching more grounds to the engine and transmission and re-adjusted the shift cable and it now drives awesome. Don't know which fixed it, probably shift cable adjustment, as I did both at the same time.

Corey