Hi Guy's,

I have a 91 RS convertible with a 700R4. The last couple of weeks when I have been doing around 70MPH on the highway my revs seem to be very high around 5K and my gas mileage has gone down. The transmission shifts ok and is not slipping its only when I'm above 50MPH.
A couple of weeks back I was de-accelerating and there was a strange noise and seems to of had the problem since.

Any ideas?

Thanks,

Alex

 

My car did something similar a while back. My problem was the governor shaft had wore down so that fluid was leaking past it and causing the tranny to stay in third gear. At 70mph, in third gear, my car ran about 5k rpm's too. $45 for a new gm governor and the problem was fixed.

 

Thanks for the reply. Where abouts is it located,then I'll go and check mine.

Thanks,

Alex

 

I get you a pic later when I go to work. The gov cover is on the driver's side near the rear or the transmission. It's about a 3 in domed cover. Just take a punch and a hammer and knock the cover off. Be careful not to crack or damage the aluminum tranny case. If yours hasn't been removed before, you might have some problems getting it to pop off. Once off, reach inside and pull the governor out with a twisting motion. Look at the shaft a check for any wear. If there is, replace it. If you notice a lot of wear, you might want to have a tranny shop check the seal that the gov shaft goes through for any wear also. I'll post some pics later to help you.

 

One easy thing to check before tearing into the tranny. From a stop, accelerate like normal and count the shifts, normally you should feel three shifts and then around 55 mph, there should be a drop in rpms when the torque converter locks up. Another way th check is to have the tranny in OD and get up to 70mph. Then put the tranny into D, be careful not to go into 2. If you don't feel any change, and you normally should, then you should check the governor.

 

Sorry, the tech pics I have won't post for some reason. If you need them, I can email them to you. Otherwise, you could buy the tech cd that is sold on this site. I have the cd and it is very useful.
One other thing that could be happening is the 3-4 band is burned up. If this is the case, you might lose third gear soon and the tranny needs to be rebuilt. With these trannys, almost anything could be the problem. I'd start with the gov. and go from there.

 

The most common problem is the loss of the 3-4 clutch pack. This can give you the 5,000 rpm you are seeing ( turn down the volume of your stereo system, as 5,000 prm should be VERY NOTICEABLE). If the governor shaft is causing you to stay in 3rd gear (somewhat rare), then the rpm increase is only about 30%, not the 5,000 or so rpm you are seeing.

 

Thanks for the replies,I'll check the governor first to see if I get off easy. I now know what that parts called now. I was going to rebuild the transmission with an HD rebuild kit, so may be nows the time. I can pick up a used trans locally for about $100.

Alex

 

Hi Ace16a,

I did the test you recommended. Put the car in D and started from standing start.All shifted ok 1,2,3 then at 70 shifted car into overdrive and the revs did drop. So looks like the transmission is fine. I have had idling problems so I think it might be something else causing thhe high revs.

Thanks,

Alex