Hi Folks, I hope everyone had a good holiday season and wish all a happy healthy 2023.
I have couple of questions regarding the C6 to T5 conversion I did on my 72 F100 with a 302.
I bought a clutch kit off of ebay with a chromoly light weight flywheel. I think that was a mistake but found out long after the fact. At least that is what I think effects how the truck takes off from a dead stop. I have been driving manual cars/truck forever and had never any issues but this thing is very jerky at the start no matter how slow I ease into it. I have a hydraulic clutch setup and I think it functions well but unless I give a lot of gas I cannot seem to get it to roll smoothly. When I give some guess though I get a little wheel spin and it picks up very quickly. Is this because of the light flywheel?
I have another issue which I believe is common to T5s. It is very noisy in neutral and quiets down when I press the clutch pedal. Based on what I read online this is due to noisy bearings in the transmission. I am not sure what is considered normal bearing noise vs what is a real problem in the transmission that needs to be addressed. The transmission shifts fine although a bit notchy no whining sound when in gear.
Any suggestion is appreciated.

 

Is the throttle linkage still the original “trapeze” style or is there a rod directly between the body and the carburetor?
If there is a just a straight rod then try replacing it with a cable style that was used on the 73 and up trucks.
Replacing the engine mounts may tighten things up some.

 

It is the rod style. Do you think the throttle is too abrupt with the rod style? Engine mounts are in good shape I had to rebuild the 302 not too long ago so all is in good shape engine and mount wise.

 

I found out a long time ago about eliminating the “trapeze”. The first time I put a 4 barrel on my engine I was in a hurry to try it out. As I eased out the clutch it jerked the throttle so I went back and re installed the “trapeze”. In your case just convert to the cable style linkage.
Still if the engine mounts are original they should be replaced.

 

Yes, a light flywheel can cause this. Especially on a carbureted engine.
It’s been a long term problem for street driven vehicles that want the better performance of a lighter flywheel.

However, without actually experiencing it, I would have no way to know, or even how to describe whether it’s the light weight causing the problem or an actual defect in the clutch friction surfaces that’s causing the jerkiness.
New stuff is hard to diagnose from this end of the computer.
Was the flywheel new when you installed it? Or was it a used one out of another vehicle?

 

Another thing that can affect this in a big way is the tire size and gear ratio combination.
What differential gear ratio do you have?
What tire size in the back?

 

Rearend ratio is 4.11. I have 235/75/15 mastercrafts all around. I am going to spend a bit of time on the clutch pedal and the gas linkage. There is room for improvement there for sure. I do not want to pull out the T5 to replace the flywheel. Last time I pulled it, my wife helped and she was not happy
Regarding the noisy T5 anyone has any experience?

Thanks for all the replies.

 

Most of that noise you hear on the T5 has been the throw out bearing in my experience. When you press the clutch pedal down and load the bearing the noise goes away. That jerky feeling you describe sounds like a bad surface on the flywheel. My tractor does the same thing now because I was to lazy to pull it and have it resurfaced and now I'm paying the price. I'm going to split it and correct the issue this spring. I'm running an aluminum flywheel in my 408w/4spd toploader setup and the clutch is smooth ans silk but does take some rpm to get it going from a stop. That's part of it with a lightweight flywheel but it shouldn't chatter like what it sounds like you are getting. Is the clutch and flywheel setup a kit or were the parts bought separately?

 

The issue is not throwout bearing, I have a hydraulic throwout bearing I got less than 1K miles ago along with the clutch, flywheel etc. So everything other than the T5 is brand new.
I believe the bearings inside the T5 is where the noise is coming from. I wonder if a thicker oil in the T5 would quite things down. I used ATF which is what Ford suggest for T5 but I used Dexron VI not the older Dexron II I wonder if that could be the issue.
Thanks for the feedback.

 

Did other entities besides Ford use the T5? If so, what lubricant did they recommend? I've seen differences in other gear boxes in the past, but don't know if it pertains to the T5 specifically.

With older gearboxes (much older!) I've always had great luck with a synthetic 75w/90 for my uses. Don't need a heavier lube in anything for hard or overly hot uses, or a heavily weighted truck (that one has an automatic trans anyway) so the lighter gear lube has worked well and has quieted two transmissions. One was a Toyota pickup mid-'80's vintage and I forget what the other was.
Just a thought, in case gear lube vs ATF is an option. I know most were going for fuel economy, so the thinner ATF was right up their alley. But many gearboxes are still designed around gear lube, so might be worth a quick try anyway.
Unless you hear that it can damage the box, it might be worth the $30 or so to give it a try.
Assuming my pricing guess isn't way outdated!

Good luck.

Paul

 

Apparently Ford went to ATF with the WC T5 around mid 80s. These WC T5s have needle bearings and gear oil is too thick to lubricate them.

 

Correct. I noticed years ago that when Ford came out with aluminum case trans, they changed to ATF. I assume this was because with aluminum, they could get tighter and more consistent tolerances than with cast iron. Thus, thinner oil used.
OP, what clutch disc did you use? Was it dual friction? Which ever clutch you used it might not be very compatible with that flywheel.

 

I bought the clutch and flywheel as a package. Here is the ebay link:
STAGE 2 CLUTCH KIT+CHROMOLY FLYWHEEL for 79-95 FORD MUSTANG GT LX COBRA SVT 5.0L | eBay

The flywheel is chromoly. It is very light especially compared to what came out of my C6 automatic.

 

What throwout bearing did you end up using and how much clearance did you set it up with?

 

I used hydramax hydraulic throwout bearing. I got the kit from American Power Train. I measured the clearance to be 0.150 inch but when I put it on, it was actually riding on the pressure plate. I pulled it out and took out 2 shims. It should be about 0.12 inch out.