Downshifting at WOT???

[Sal 87WE2]

Hey all, took the GN for a spin and i hit the gas in 2nd gear and took off. The rpms starting to increase and i was at full boost and then for some reason it decided to downshift into 1st instead of running through the gear and upshifting. This happened a couple of times on test runs today. Any idea what is going on?? Keep in mind this was at a higher RPM and should not have kicked down at such a high rpm... I redlined the heck out of it...

thanks in advance for any help.

 

[jakeshoe]

My initial guess is that the band is releasing at high rpm due to pressure loss from pump starvation.
Deep pan?

 

[Sal 87WE2]

My initial guess is that the band is releasing at high rpm due to pressure loss from pump starvation.
Deep pan?

Negative. Stock pan.

Recently had tranny fluid/filter change. Maybe low on fluid? I Didnt bother to check after my tech did the work...

 

[black86gn]

Always check your fluids...that is number one. These transmissions can do funny things with 2004r filters especially. Let us know if it was low. Should be overserviced by around a quart or so.

 

[Sal 87WE2]

Always check your fluids...that is number one. These transmissions can do funny things with 2004r filters especially. Let us know if it was low. Should be overserviced by around a quart or so.

10-4

Great advice, still have not been near GN but will check fluid AND overfill by a quart today for sure.

Thanks!!!

 

[Sal 87WE2]

OK, drove GN about 5 miles, nice and warm. Check Tranny Fluid and looks like over a quart full. I never added anything.

What next?

 

[turbo nasty]

Negative. Stock pan.

Recently had tranny fluid/filter change. Maybe low on fluid? I Didnt bother to check after my tech did the work...

Did it work right before fluid change?

 

[black86gn]

And what type of fluid was used? A synthetic could possibly cause problems. Make sure that type F was used.

 

[Sal 87WE2]

Synthetic was used because that was the only thing they had on the shelf at parts house i went to. Dexron.


I think maybe it happened a couple of times before as well... I really cant remember, i drive it once every other week sometimes once a week...

 

[black86gn]

First thing I would do is replace that synthetic atf with some type F. A lot of times synthetics can cause problems in automatics because the fluid reduces friction a lot. You need a little more friction so that clutches grab faster along with everything else that is applied in the transmisison such as your bands. So if you want, you can try draining what is in there right now and replace it with type F and hopefully that will fix or maybe even cushion your problem. If not then you may be looking at a rebuild. I do know that once you slip a band the damage is permanent and will continue to slip until replaced or upgraded....in some cases you can adjust bands to reduce slipping but am not sure for our specific gearboxes. Good luck with it and hope that you have good results.

 

[77 cruiser]

Get a pressure guage on it & test.