I have an 02' Mustang GT Premium. I just finished swapping the motor with another 4.6l 281ci that was a little beefier with a few more mods. The motor I put in was freshly rebuilt with fully forged internals and a roller cam. However, the motor was on a fairly stock tune. Sunday night, I was comming down the interstate and noticed a horrible shake between 50-80mph, but once the car was outside of that range it was fine. I tried opening the car up to see what would happen. The car handled fine with no shake over about 90 all the way to 160. When I allowed the car to rest back down to cruising speed, the shake occured again. I pulled over to the side of the road and I heard a sound something like the unwinding and popping of a spring. Then the car was stuck in gear. Even when the stick is in the neutral posittion, the car still attempts to go forward and dies when the clutch is released. I lifted the back tires and i cannot turn them even with the car off and the stick in the neutral position. Do I have a rearend problem or is it just the trans?

 

It has to be a transmission issue, purely speculative of course I could see a bad pilot bearing leading to a broken main shaft as a cause of what you describe--are you sure the newly rebuilt engine had a pilot bearing installed?

 

No. I am not sure whether or not they installed a pilot bearing... Am I better off buying a used trans or having this one rebuilt? The new motor has just over 300hp so I am thinking that the original t3650 wasn't designed for that kind of power, especially when it was constantly called upon. lol

 

I have recently aquired a 97 gt and the car has been running great until last night when i left the parking lot it wouldnt shift out of first gear until it redlined then it shifted. so now i have to manually go through the gears to get a smooth shift pattern or run first gear out till it hits 7k rpm and then it will shift out like it should. iv changed the filter and fluid. also had afriend of mine tell me to disconnect the tail housing speed sensor and see if that does anything. the only thing it did was give me a code and then i had to do the same as above. can anyone offer any advice?

 

There are people running 500 to 600lbft through the 3650. It is a robust unit rated at 360lbft input (transmissions are rated by torque capacity, not HP).

At 5252 engine rpm that would be 360HP, As I said this is the manufacturer's rating, it can handle quite a bit more--here is a good read re: the TR3650.

 

Please take this as constructive criticism:

Why don't you start a new thread about your automatic transmission problems, rather than hijack a manual transmission thread?

 

When my T-45 took a dump on me it would be stuck in gear even if the shifter was in neutral and when I let the clutch out with the shifter in the neutral position it would jolt forward and die. The guys at the shop told me it was the clutch forks that were shot. I didn't inspect the trans because I swapped in a 4r70w but I don't think my pilot bearing blew up, trans just didn't like powershifting anymore.

Also, I didn't notice any shaking when I was driving the car back. My trans was stuck in 1st.

 

Sorry to all who were offended by my posting of the auto trans post. I though this was a transmission thread in which we could post about any trans problems.

 

There was no "offense" taken (???), the point is that your issue would stand a better chance of being responded to in its own thread with a subject line such as "97 GT, auto trans not shifting as it should" or the like.

 

im no expert when it comes to transmissions however a friend of mine had this same problem and his clutch was toast, it shattered, im guessing the unwinding and popping of sounds was your clutch taking a dump?, he replaced it and the PB and TOB just to be safe and its fine now.