2 wheel burnouts bad?

[laxmax327]

still running on the stock diff. know all about its faults and the 1200 fix for it. i know quaife is the best bet, but i honesly like it perfectly fine as it drives now, i dont autocross it or anything. the only reason i would ever buy a quaife is to prevent the horror stories i hear so often. has yet to hapen to me though, and i do give my car ****. i thought one of the main causes of the pin failure was from doing 1 wheel burnouts. well dunno why others do it, but mine will only do 1 wheel if im cornering hard or something, but if its straight, its always both wheels. so how safe is this for the diff? i drag the car alot and have never experience 1 wheel spins. am i due for a blown diff or what? this thing has been abused for months now. also has ripped through many tires in that time.

 

[omeara7]

Count your blessings...a blown diff pin can happen pretty much at any time. My 92's went when I was driving it really casually (shifting at less than 3,000). I heard the pin bouncing around in the tranny case and I had a very good feeling it was about to blow but I was on the highway. Unfortunately I was right. Your best protection against a diff-failure is no burnouts or chirping gears (slam shifting)....period. I also changed my trans fluid to Pennzoil’s Synchromesh gear oil which I think was a bad idea because IMO it's too thick, which might have prevented enough lubrication from reaching all parts of the differential.

 

[Huntervf]

I know people who've beat the snot out of their stock MTX drivetrains and never had a problem.

I blew a diff at about 80k in my 95 MTX, the first SHO I'd owned. I'd done a lot of burning out & hard driving and it went at 7k during a 2-3 shift.

On the other hand, the 89 I had saw a heck of a lot of abuse as well. Lots of hard starts, lots of 1/4 runs, lots of smoke & rubber and plenty of chirping the 1-2. I stripped 3rd gear thanks to a heavy duty race clutch, but the stock diff at 130k was a-ok.

There was another guy I knew back in Kalamazoo... his nickname was burnout if that tells you anything. 93 MTX with 170k on a stock diff and that car would lay two strips for 100 ft. on demand.

And yet, I've known people who had a pin pop while leisurely crusing on the highway.

It is known that one wheel spinning can stress the diff, and that most failures are the result of this stress combined with inadequate lubrication. In the end it just comes back to the old saying, if you wanna play you gotta pay. You may get lucky, or you may blow the diff. The only guarantee is a quaife, or drive your SHO like it's a carton of eggs without the carton.

 

[laxmax327]

yea i guess thats what i kinda expected. i have to options here. and guess what, i refuse to drive my sho like a puss. so i guess im goin to be looking into a new trans. i think im just goin to buy an extra to have sitting around so when mine goes boom, i can pop a new on in pretty quick. and like omeara was saying sort of, would switching to a lighter viscosity oil possibly help w/ the life of the diff? seems it would help keep the pin lubed, but i suppose the downside could be slightly tougher shifting. ( which i have no problem with)

 

[Huntervf]

When my pin blew I was running plain ol' factory fluid. Don't even know how much was in there to be honest. After that I ran Royal Purple synthetic ATF, which was uber slick but made shifting a little harder. I started RP in my 89 but later switched to GM synchromesh, which made shifting an absolutel pleasure. I've since stuck with synchromesh.

I've talked with Contour owners who ran Redline in their trannys, and the fluid completely broke down. I've seen some very nasty pictures of cracked open MTX-75 trannys that had been running Redline. I wouldn't touch the stuff.

This gets me thinking... I'd be VERY interested to see what kind of fluid was being run in these MTX-IV's at the time of diff failure. Not sure a study like this has ever been done.

 

[laxmax327]

yea, ive been thinking about that too. what if the diff pin failure was related to the fluid inside? that would be an amazing large breakthrough for us. i think we should start some sort of poll or something. try to get all the ppl who have had failures state what fluid they currently used. ill let you do that hunter since your a mod and have all those cool powers but seriously, i think we should at least look into this a bit. only prob i see would owners not knowin what was in there.

 

[shoebilly]

diff pin failure really is'nt related to ****. This occurs from shock to the pins and the pins don't fail, the roll pin that secures the pin in its position starts cracking eventually allowing the pin to walk out of its housing and consequently tearing the **** out of the case. The pin will ride loose inside the case for some time wearing away the aluminum til one day it just pops threw the case doing major damage. If the fluid has a high content of very fine aluminum flake it is probably near failure. The roll pins can be replaced beforehand and this would remedy the problem unless you cant help but spin the tires. Spinning the wheels is death to the tranny and other failures.

 

[SHObill]

Just call Beth & have her reinforce it for you. No need for a Quaife!

 

[omeara7]

yea, ive been thinking about that too. what if the diff pin failure was related to the fluid inside? that would be an amazing large breakthrough for us. i think we should start some sort of poll or something. try to get all the ppl who have had failures state what fluid they currently used. ill let you do that hunter since your a mod and have all those cool powers but seriously, i think we should at least look into this a bit. only prob i see would owners not knowin what was in there.

I was thinking about this the other day. I totally agree that somone should create a poll or something that asks victims of blown diff pins what kind of fluid they were running at the time of failure. I can't help thinking that the thick pennzoil syncromesh stuff that I was running had something to do with my diff blowing. Now, I have Mobil 1 ATF in there so we'll see.

 

[DVJ38]

So who's starting the poll, I am interested as well. I don't think that has been discussed before really.

I second HunterVF!

 

[TYSHO]

what if the diff pin failure was related to the fluid inside? that would be an amazing large breakthrough for us.

Anyhow, I've blown a differential with whatever my SHO came with, plus a top off of Quaker State Type-F. I blew another one with Castrol Type-F. I then blew another one with Motorcraft Type-F, and I think another with Motorcraft Mercon.

Since then, I came up with my own design and reinforced the differential. Never has my SHO been so reliable while taking so much abuse and burnouts. I now run Motorcraft Mercon-V.

 

[ManySHOs]

They have run all different types of fluid. Any poll that you take won't bear much significant meaning because there are way too many variables involved. (level of fluid, quality/age of fluid, was this type of fluid run the entire life of the transmission, type of driving the car experienced, mileage, etc).

In NJ there's a group of us that have been really good friends for the past 7+ years. We all own or have owned SHO's. 3 of us have blown diff pins, sometimes more than once. We've all run different types of fluid as well.

FWIW, I never had a diff pin failure but the rivets on my stock diff had a ton of play and were coming apart. The ring gear looked like it was going to seperate from the diff. When Mark Nunnally took my transmission apart he said that it was the first that he had seen like that and the second that he had heard about. Of course my transmission only had a few drops of dirty fluid in it when I bought the car at 70K. Yikes.

There is only one proven solution. Quaife.

Ian

 

[shoebilly]

Diff pin failure is NOT **** related. It is FATIGUE related.

 

[AREA 91]

First diff I blew.....stupidity.......2nd..... even more stupidity......solution...QUAIFE.....

Quote "If you beat it, it will blow!"

 

[ManySHOs]

Just a thought laxmax327; what will you do when you blow the diff in your replacement transmission? Your original trans may not be useable if you blew a hole in the case...

Ian

 

[Mac]

I did a couple burnouts, and they were all 2 wheel. Then my diff blew.

 

[Huntervf]

Still... I've seen just as many if not more MTX's driven hard--including fairly regular smokies--than MTX's with blown diffs. If it's a straight coorelation between hard driving and destruction it would be one thing. I'm not saying hard driving and abuse isn't the cause of diff failure... but if it were the only factor I would expect every abused MTX to throw a pin and fact is not all of them do.

Just trying to think outside the box here a little bit. Over 7 years I've owned 4 MTX SHO's with open diffs (and 1 with a quaife ) and experienced 1 diff failure. All received at least some smokey launches. All definitely received hard, quick shifting and in the case of my 89 it saw lots of 1/4 time and a few autox / roadcourse events.

9 times out of 10 my 89 would light both front tires, given a straight launch on a level surface. However, my 95 (the one that blew the pin) would almost exclusively spin the driver side, even on a straight launch.

There certainly is a little example right there of stress on the diff causing a failure. What interests me most however is the difference between the two cars. Given equal conditions, what would cause the difference in tirespin between the same engine/tranny combo?

 

[revhardSHO]

I have had a few SHOs and Ive never had a diff pin problem. I think the majority of the failures come from abusive driving where the driver has no understanding of drivetrain control. Example: Dropping the clutch at 7,000 rpm, with total disregard for the harsh shock that puts on the clutch, motor mounts, transmission, transmission, axles, etc. I will drive aggressivly but at the same time I know the driveline has its limitations. There is a fine line between "Aggression" and "abuse", but if you know the difference, your car will thank you.

For everyone who has had your diff pin fail on the highway, it did not fail from highway use. Sometime, somewhere in the past, the diff had been tweaked, a pin had been sheered, and it was ready to blown, most likley from a burnout, or hard driving. It just so happened you were on the highway when your diff decieded to ventalate the case.

 

[shoebilly]

There hsa been a pin kit available(i think form ford)that comes with solid pins instead of the spilt rollpin.I'm told this pin fastener is not as good as the original.

 

[TYSHO]

Diff pin failure is NOT **** related. It is FATIGUE related.

It's a combination of both.

****: When the inside of the differential is lacking ****, the spider gear(s) gall the shaft(s), forcing them to twist. When this happens, the roll pin holding the shaft in place gets worn. After many times, it will shear and the shaft ejects out of the differential. And it doesn't help that the shaft already has play in it, as-is.

Fatigue: When you dump the clutch at high rpms, the differential receives a shock. This shock puts stress on the roll pin that is trying to hold the shaft inside the differential, and it just so happens to put the stress in the same area as the **** wear. Not only can dumping the clutch do it, hard braking will do the same as the roll pins are trying to keep the shafts in place.

When you combine all of this together, you're running on borrowed time.


When I reinforced my differential, I had two things in mind: How to keep the shafts from ejecting, and how to make the shaft have zero tolerance of play.

The **** reason is the only reason I use Mercon V and recommend to use a transmission fluid that is either semi-synthetic or full. IMHO, synchomesh is too thick for the differential.