I have now owned my car over 16 months and sadly, when I test drove it they lived on a back road hours from any straight that I could get it up to speed and test o/d. (Besides, the car had bad brakes and a front wheel bearing that was bad so bad that whiles turning, the wheel would buckle in causing the whole thing to shift on the road).

Anyways... I drove it home and realized on the way home that it doesn't have overdrive.

Fast forward to now... I have taken the car on several road trips including 250 miles to indiana and back, 90 mph for 2 hours one way to kentucky and back, and down the interstate several times here including speeds up to 105mph.

Every time I get into it and drive it, I put the car into D (third gear) and drive it around.
I installed an aftermarket trans cooler and flushed the trans (which was red fluid still after having owned it for 15000 miles) and drove it to indiana, when I got back, the car started not going into 3rd. I checked the trans cooler and it was cold except where the lines went into the cooler it was very hot. I changed the trans cooler and now it has absolutly no problem shifting into any gear, except 4th.

When I got the old cooler off, I decided to let it set and drain only to find some metal shrapnal and the old cooler is definatley clogged.

So, is it possible my car doesn't have 4th gear anymore?any other input as to the problem?
Also... am I hurting it driving in 3rd? Like I said, I have had the car for 30,000 miles now and most of them travelling the interstate at 70-75 mph mostly and that's about 3100 - 3500 rpm.

 

3100-3500 rpm sounds like its working pretty hard to keep those speeds and killing gas mileage. When my shift pressure solenoid went out, I couldn't tell anything was wrong but I also lost OD and then I lost 3rd.

 

Well, when I tried putting it in od, the rpms go up, then settle back in. When I let off the gas in od, the rpms die down to idle and when I go to press the gas to keep at speed, they will go all the way back up to 3100 (or differant depending on speed) then engage.

I spoke with my mechanic who I've known for years (and who has taught me everything I know about cars and working on them) all he said is that its acting like its in limp mode for some reason and that as long as I keep it in D (3), it wouldnt really have any negative effects except on the gas mileage.

 

The only thing that will happen if you stay in 3rd (Drive) is that you will lose mileage, and that is obvious by your rpms. Overdrive at 70-75 should be around 2300-2500rpm. Your 4th gear shaft probably went out a long time ago before you got it from the sounds of it, especially if the tranny fluid looked good like you were saying. There is the possibility that whoever owned it before you might have flushed the tranny fluid to get rid of the metal shavings that would have been in it. You'll never know though, so you need to check the pressure solenoid and if that doesn't work, go into the tranny. It's common for 4th gear to go out on these trannys.

 

if you seen heavey metal coming out of the trans cooler there is some thing very wrong with the trans. i will drop the pan and check the magnet on the pan if there is alotof shavings on it imo i will go get a used 4t65e and have it rebuilt or get the one that you have rebuilt. because it sounds like the clutch or some gears have suvere weir and grounded out in falure

 

I would have it rebuilt instead of getting a used. i replaced the 4t65e in my old bonneville with a used one only to the it fail 3 months later, hence why I now drive a monte