Transmission, no overdrive and not shifting under WOT

[jshaw]

I am fairly new to Grand Nationals and automatic transmissions. I purchased a Grand National several months ago, and have been going through several problems (replaced turbo, shorts in radio, new window motors, suspension, etc). Now I am going through the transmission issues. From the receipts, it looks like it was rebuilt about 15k miles ago. I think the best way to express the problems is as a list:

• Does not seem to go into overdrive
• The shifter seems to detente in only 3 forward positions (it feels like it will not stay in the first gear position if not held)
• 2nd gear position acts like first (only 1 gear), 3rd gear position acts like 2nd (2 gears), and overdrive only seems to go through 3 gears
• It doesn't seem to shift under WOT, I have to let off of the gas

I haven't yet adjusted the TV because the adjustment is stuck and the problems I've read about don't seem related to these problems.

The most similar problem I've seen in forums related to the overdrive and WOT has been with a spring on the governor. I assume the strange shifting detentes could be a linkage issue.

I want to get some input before I start blindly tearing things apart. I have it on the lift right now, so it is pretty simple to run through the gears for suggested diagnostic purposes.

Any suggestions?

I do not have a pressure gauge or line for the transmission, but I guess I probably need to look into getting one.

Thanks for the help!

 

[Shawn N]

Could be a number of things from burned up clutches to a burned up converter. I suggest you find a brf 200r4 expert in your area or buy a replacement from a vendor here. Do it once and do it right.

 

[TexasT]

When you say the shifter doesn't want to stay in first, are you feeling it in park? Then as you move the lever do you feel the detents for reverse, neutral, od, 3,2 and as you said won't stay in 1? You might have the trans in d or 3 and that might be why it won't shift into od. Are you feeling the converter clutch lock up?
If it isn't shifting at wot the common prob is the governor spring coming out. While you have the pan off you can see if the tv cable is pulling the valve fully open.
A gauge is the best way to determine if the tv is doing what the trans needs. If the pressure isn't jumping when the cable is pulled something needs to be addressed.
Are you familiar with the governor and its four 10mm bolt cover? You should consider "pinning" the spring while you have it apart.

 

[jshaw]

It took me a while to get back to this, but I wanted to write up what I found in case anyone has similar problems.

The reason I was having problems with only 3 forward gear positions was that the bracket holding the cable sheathe to the transmission was bent. When I bent it back, I was able to engage all forward positions.

It also seems that the car is now going into overdrive. It might always have been, but it was simply shifting at such a low speed that I never realized because I could never get it into first. I did put it in the air, get it up to about 80 MPH with the wheels off the ground, and punch the gas several times (per the suggestions of a 2004R website I found), but I do not know if that had anything to do with correcting the problem.

I would like to thank David Husek for talking me through some of the specifics of this transmission.

As far as the not shifting at WOT problem, I have not had a chance to get on the gas enough to diagnose it. I need a bit more space without people and traffic to better sort that out. Next time I have it on the lift, I might just go ahead and drop the transmission pan to look at the governor. Thanks for that advice, TexasT.