T-5 problems.

[wythors]

The background: Recently completed a T-5 swap into my AOD car. Bought a used T-5 from a friend of a friend that supposedly came out of an 88 Saleen with about 80,000 miles. Installed with aluminum flywheel, King Cobra clutch kit and a used FRPP aluminum driveshaft that came out of the same car, though supposedly with less than 10,000 miles on it. Drove the car, HATED the way the clutch engaged and the low speed driveability with the aluminum flywheel. Also, and this is the problem I'm seeking help with, there is an incredibly violent vibration under load in 4th gear. So, I swapped out the aluminum flywheel for a new cast iron one and reinstalled the stock driveshaft, thinking that perhaps the aluminum one was out of balance or had a bad U-joint. The cast iron flywheel cured my problem with clutch engagement and low-speed driveability, but the same vibration is there in 4th gear. The shifter handle vibrates so violently that you almost can't grab and hold it. Also at 95 mph + in 5th, there is a deep, thrumming vibration that seems to increase with speed. Other than the vibration, the thing shifts smooth and crisp and makes no noise at all.

My assumption here is that the bearings in the tranny are FUBAR. Any other educated opinions?

 

[cenok is family]

i'm sorry to hear about your troubles. my old transmission used to do that. INCREDIBILY violent vibration/shaking when above about 4000 rpm. i have a few t5's sitting in my garage so i got one rebuilt and threw it in. cured the violent part of the vibration but it still vibrated at 65+mph speeds. obviously that was a u joint, so i bought a new ford racing aluminum driveshaft from latemodel about 3 weeks ago, i now have ZERO vibration in my drivetrain. i agree with you on the bearings in your t5 being shot. get it rebuilt for about 400 and use the aluminum shaft.

 

[795.0pacecar]

It sounds like it could have a bent tail shaft.

 

[wythors]

It sounds like it could have a bent tail shaft.

I would think that that would manifest itself in all gears, not just 4th.

 

[795.0pacecar]

As would bad bearings considering all of the gears and shafts are always turning while the car is running. Also bearing problems almost always make a lot of noise. Harsh vibrations are usually some kind of balance problem. I would pull out the trans and pull it apart to eliminate some of the guessing going on here. To be honest with you, I never would have put in an 80,000 mile trans without rebuilding it first.

 

[ninety15.0]

I have a similar problem. I dont have any harsh vibration under load. But i do have a deep humming/pulsating noise that only shows itself when driving in 5th gear above 80mph. So i try not to cruise any faster than 80 for fear of making the problem worse. I had my stock driveshaft re-tubed and high speed balanced with all new u joints. That cured all of my vibration problems but did nothing for the high speed humming/pulsating noise in 5th.

I have always thought in the back of my mind that it was a bent tailshaft or something along those lines. who knows...i'll wait till the stocker t-5 gives out on me. 160k and going strong...kinda