281GT

So a few months ago I purchased two sets of FRPP 8.8 4.10 gear sets. I installed the first set into my Ranger with zero problems. Tooth contact pattern and backlash were perfect on the first attempt and the gears run perfectly quiet.
Today we installed the other set of FRPP 4.10 gears into my '05 Mustang GT. This instalation did NOT go so well. Had to do it 3 times before we could get the backlash right. We had to use a .0035" shim to get the backlash right which seem really odd as the stock 3.55 gears had a shim of approx. 0.027" and the smallest shim included in the kit was 0.010".
So after all this the gears whine on coast. They are quiet on acceleration and quiet on deceleration but driving a steady speed with light load they whine. I also have a vibration that starts around 62 mph and gets worse the faster you go. I had no vibration at all before the gear change.
Due to the fact that we had to use such an unusually thin shim I am wondering if anyone thinks I just got a bad set of gears?
Any opinions are welcome. Thanks!!

Chilliwack 42

Not to sound like an a$$hole, but you've done this before right? Installing gears can be alot harder than most people think. Did you paint the teeth with gear marking compound or did you just do it by eye?

RUgoinUp?

He said he did his Ranger, so he's done it before. He also said the pattern was fine on the Ranger, so I'm sure he used the compound on his stang.

281, I have the same issue right now with a set of OEM 3.73's (vibration at higher MPH). I do not believe it's defective gears. For some reason the gears in these cars tend to walk due to pinion movement...what's causing the pinion to move, I do not know. I'd be willing to bet that if you removed your cover you will find teeth marks on your carrier from the gear walk. Mine have it, but my mechanic thought it was no big deal and reinstalled everything (checking backlash only) but the problem didn't go away.

Before I spend more $ on a new gear, I'm trying to find out what the cause is. Please keep us abreast of your situation. I'll check back if I find anything.

RUgoinUp?

Here's a post that explains a little of it:

281GT

I've done quite a few set of gears in Chevy 12 bolt diffs and a Ford 9" in addition to my Ranger. This is the first one that I've had gear whine with. I did use gear marking compound and the pattern looked ok. What I've decided to do is to try and get an assortment of shims for the sides of the carrier, move the pinion back to where it was and try and get things lined up by adjusting the carrier from side to side.
I'll post here the results.
RUgoinUp. thanks for that info. I guess if this next process doesn't clear up the noise I have a bad set of gears.
In the mean time I'm not driving the car until this is sorted out.

281GT

Well between my crazy schedule and my friend's equally crazy schedule we finally got around to completing my 4.10 gear installation. What I stated earlier did turn out to be the final solution. We moved the pinion back to where it was when we started by using the original 0.027" shim and then moved the ring gear away from the pinion. First we moved the ring gear 0.015" away but that proved to be too loose. We had almost 0.020" backlash with that change so we moved the ring gear closer by 0.007". That did the trick. This setup produced 0.010" backlash and a tooth contact pattern that looked perfect on both sides.
Took it for a drive and no noise under any conditions. Had her up to 200 kph, no noise whatsoever under cruise, coast or acceleration. The 4.10's are just as quiet as the original 3.55's were.
So this Friday it's off to the track to test!

70MACH1OWNER

I bet the air is good up there this time of year. Please post your results!!
Scott

281GT

Yeah it's getting cool for sure and the air is great! Only problem is that our track is at 2200'
Stock S197 GT's run between 14.50 and 15.00 here.
My best run with the 3.55's was 13.75 @ 103.05 mph.
I think I'm gonna have a pretty bad traction problem but I'm hoping to gain a couple more tenths. Next on the list is a set of sticky tires and a line lock.

70MACH1OWNER

That is what I was thinking when I was reading this post....You need tires!!!
Scott

don_w

2200 isn't too bad. The track I run at is 1700. Just be glad you're not in Denver at like 5800.

Cdvision

Ya if the weather holds up it should be good at Castrol Raceway. I wanted to go tomorrow but I have to go to the mother in laws 50th b-bay dinner(unless I can ditch work early and get a couple of runs in before dinner). My buddy Claudio with a red 06 GT rag top should be there. He typically pulls of mid 13's. I still haven't cracked the 12's yet (13.11) but Rick in his yellow procharged 05 ran a 12.25 last week.
I might not make it out again until spring. I've got to get my tune sorted out and install my Prothane motor mounts and CHE k-member still. I'm shooting for a 12.75-12.85 for the spring. Maybe I'll see you out there.
And yes you need some drag radials. Rick and I are both running M/T ET Street drag radials 295/45-17 and they work awesome.
Next year I want 4.10's and a one piece driveshaft and loop. But I've gotta pay off the Whipple first.

281GT

I was thinking of MT ET streets. I think I'm going to price a set today. If I can get them for a reasonable price I might put them on for this evening. I hope the weather holds!

Cdvision

Call Gramae at JB's north 406-7030

SoFlaBoss

I already have the line locks and M/T ET Streets. I just need the 4.10's and cool weather! Also, I haven't raced in over 30 years, so I need some track experience too.

Sharky

Moving from Colorado Springs 3 years ago @ 6900'... I can tell you that:
a. Octane over 91 does not exist within 200 miles.
b. Had to take my F-150 to Ford for a reprogram for high altitude.
c. Forget your car breathing... it took me 6 months to be able to walk a flight of stairs without panting like a dry dog.
d. Sorry for going off topic.

don_w

I used to spend time checking prices, but I found out very few (if any) can beat Summit... and they generally arrive on my doorstep 2 days after I order them. I won't buy race tires anywhere else.

281GT

Thanks for the advice Don. I have bought a few things from Summit and I have had good luck with them but I never would have thought to look there for tires.

Went to the track tonight. Yep, I DESPERATELY need better tires. The best I could muster was a 13.6 @ 103.0 mph. Basically I have no traction in 1st at all and second gear isn't much better.
Season is almost over here so I guess I'll wait until spring. I hate winter.

don_w

Summit is usually the first place I look for everything (unless it is a specialty part). You just can't beat their prices and quick delivery most of the time.



hahah... from my perspective, the "season" is just getting started. Other than the occasional rain, I prefer winter here. That's when we get our best air for drag racing. The next 6 to 8 months will be fun!

ChevyKiller

^^^ Ditto. 'Racing season' is just getting ready to start for us. Can't wait to run in some cool air for a change!