Rear tires locked while driving - clutch issue?

[azshelby350]

As I continue to sort thru the issues and quirks on my ex-Ford Performance Racing School track car, I experienced a strange occurrence that I am trying to diagnose:

I was in 2nd gear about 6k rpm slowing for a right hand turn on the street. Out of nowhere both rear tires locked momentarily and slid for about 10’ or so and then released. Afterward the driveline was making a subtle rotational noise. I put the car on jacks and ran the car and checked everything over but couldn’t see any obvious issues.

I’ve experienced a grind on nearly every 5-6 or 6-5 shift regardless of rpm and clutch engagement. The car has also tried to pop itself out of reverse on a few occasions. I have a Gen2 MGW shifter on order as well as a McLeod RXT clutch.

I am thinking the clutch is shot, maybe scored, and/or the flywheel is warped and “catching” from time to time. It felt like I didn’t match revs between a downshift under load and it sent the mismatch thru the driveshaft into the differential. Anyone have any ideas or similar experience?

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[sk47]

Hello; Since we are guessing at this point my guess is the issue is not the clutch. Guessing only I would think the clutch would slip if the disk or pressure plate was the problem.

My first guess as to the actual issue is the transmission. I have rebuilt a transmission or two and have been fooling with the gears moving on their shafts. I could get the gears out of position enough to lock everything up. The space between the rotating gears is tight. Just a guess to be sure. The grind between 5-6 shifts likely is a clue.

Second wild guess is something is floating around somewhere in the rear end but do not have in mind what would lock up both rear wheels.

I will follow the thread in hopes to learn what happened.

 

[Inthehighdesert]

I think your on the right track. That sure sounds like an internal issue on the transmission. Rear ends are usually good, noisy, or shot, not intermittent. Clutch’s typically chatter and slip when at the end of there service interval.

Hello; Since we are guessing at this point my guess is the issue is not the clutch. Guessing only I would think the clutch would slip if the disk or pressure plate was the problem.

My first guess as to the actual issue is the transmission. I have rebuilt a transmission or two and have been fooling with the gears moving on their shafts. I could get the gears out of position enough to lock everything up. The space between the rotating gears is tight. Just a guess to be sure. The grind between 5-6 shifts likely is a clue.

Second wild guess is something is floating around somewhere in the rear end but do not have in mind what would lock up both rear wheels.

I will follow the thread in hopes to learn what happened.

 

[silverbullet85]

If you were going to fast and then downshifted into 2nd gear that would cause the tires to lock up due to the sudden decrease in rear wheel speed

 

[Firsttexan]

I hope they give big discount on racing school cars?

Popping out of reverse, sounds like a worn trans.

 

[Whopperman]

Had someone I know with the same issue with his 5th gear. On every downshift it would grind bad, but on most upshifts it wasn't that bad and it ended up being the syncros on his 15 gt. I know they are different transmissions, but just some knowledge I'm sharing

 

[azshelby350]

If you were going to fast and then downshifted into 2nd gear that would cause the tires to lock up due to the sudden decrease in rear wheel speed

I didn’t downshift - I was in second on the street accelerating from a light until I slowed for a turn.

 

[azshelby350]

I hope they give big discount on racing school cars?

Popping out of reverse, sounds like a worn trans.

The cars were sold at a large discount and I’m only using it as a track car, so I expected some issues. To some degree it’s fun chasing problems and learning more. Good news too is I was planning on replacing the clutch and such anyway.

 

[Inthehighdesert]

When you have the tranny out pop the top, it’ll tell you everything you need to know.

The cars were sold at a large discount and I’m only using it as a track car, so I expected some issues. To some degree it’s fun chasing problems and learning more. Good news too is I was planning on replacing the clutch and such anyway.

 

[Cobra Jet]

Did you get any illumination of lights in the dash cluster when it happened?

Possibly could be a binding issue with the rear diff… but one would think this would occur more often and not just a single instance.

Check the rear thrust washers on both sides. When those are failing they cause all sorts of issues with driveability and with tire/abs/steering warning light weirdness, see here:
https://www.mustang6g.com/forums/threads/abs-advancetrac-power-steering.162475/#post-3308430


Make sure the clutch pedal safety switch isn’t loose or has fallen off. See this thread:
https://www.mustang6g.com/forums/th...s-breaking-off-solutions.165464/#post-3366792

Also check this thread too. There is a small pad for both the clutch pedal and the brake pedal. If that pad falls off of either location, it causes quite a bit or weird shit to happen with the operation of the car. This is all the info you need (brake pedal and clutch pedal switch “pads” are the same):
https://www.mustang6g.com/forums/threads/brake-light-switch-near-pedal-failure.122100/

 

[Rapid Red]

Yes to the transmission, red flag, pops out of reverse. Old track car shows its age. Transmission grenades (locks) & breaks the case you'll be regretting that.

Running it hard with what's described, could be seeing this in the rearview ====== bang the end.

All kidding aside have it checked. If doing your own work get it in the air, drain & check the oil................ soon The more noise it makes the higher the repair cost.

 

[JeremyPro5.0]

IF you pull the tranny and overhaul it now, you should be able to save it.
Wait much longer and have it go bang, may be nothing left to really save if it shreds.

Bets of luck.

 

[azshelby350]

Thank you Cobra Jet!

 

[azshelby350]

Yes to the transmission, red flag, pops out of reverse. Old track car shows its age. Transmission grenades (locks) & breaks the case you'll be regretting that.

Running it hard with what's described, could be seeing this in the rearview ====== bang the end.

All kidding aside have it checked. If doing your own work get it in the air, drain & check the oil................ soon The more noise it makes the higher the repair cost.

The transmission is coming out in a couple weeks to install the clutch and shifter. I have not had the car on the track yet as I am ensuring all apparent issues are addressed first. I’m having the work done by my local dealer because I’m friends with the owner. The Ford Performance tech is the one who will do everything so I’ll have him look into the trans and was also going to have him pull the diff cover and check everything back there and swap fluids.

 

[azshelby350]

A couple more things to add for y’all’s input — At low RPMs there is an audible “rotational” noise coming from the center console area thru the shifter. Also, while slowing to a stop with the car in gear the car pulsates through the pedals, almost like there is a warped front rotor. A buddy in my Shelby group with lots of mechanical and technical experience with race cars think the clutch flywheel may be warped and/or the pinion bearing is shot causing the clutch to lock up and shutter momentarily. I’m still waiting for Lethal Performance to ship my clutch and shifter.

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