Please help with ring and pinion install

[Febulous]

Ok, I have a 94 gt I recently put a set of 3.73 gears in, here is my delima I have had some issues with a high speed vibration. At about 90 on the speedo which until I change the speedo gear is only about 70 I assume I get a very bad vibration. So we assumed the gear was running too deep and increased the backlash. However with that done I still have the same problem, vibration at "90" the vibration did decrease slightly but still is far from being correct. I have to think that we have the pinion gear shimmed too deep but before I go through the trouble of tearing it down again, I want to talk to someone that has been in this situation before and can tell me from experience rather than me having to guess again. Any info would be greatly appreciated.

Chris

 

[AznStanger3v]

did you get on it as soon as you were done? a lot of people F up like that. you need at LEAST 250 miles to be safe so the ring and gear seat themselves together correctly. we'll take it from there.

 

[Maxboost50]

I have had a set done from a professional, and I have done a set myself. With both, they had a slight vibration at about 70mph. The first set I took back to the guy. The first set, the shop I took it to, put a different drive shaft on, and it helped a bit. With the same car, I took it to some of my racing buddies, and they said it was normal. I changed the set in my 95 myself, and never even worried about the vibration. Maybe, have the drive shaft balanced.

 

[Febulous]

I thought about the driveshaft, but it was running smooth up to 120+ the day I pulled the stock (but worn) 3.08's out of it. I still think that my problem is that the pinion is too deep, simply because my brilliant father-in-law couldn't find my shim pack and since he happened to have a .045 shim laying around he had that pressed on my pinion. Granted the shim we pulled from the old pinion was .035 but that seemed excessive to me let alone adding 10 thousanths to it. I'm just tired of the guessing game, been it 4 times now, lol. Think I'll go to a professional soon. That or put a 9inch under I've done multiple third member ring and pinions.

thanks for the info guys

 

[JJ95GTID]

I marked the driveshaft and flange to make sure it went back on the same position it was before the swap.

 

[89MustangGX]

Are you really just guessing and not measuring? Not a good system at all.

The vibration is most likely from the driveshaft, you'd probably get more "noise" out of a rear not setup correctly than vibration (don't ask how I know). The RPMS you'd be spinnign at about 120 are now what you spin at lower speeds, that's why most people go to an aluminum driveshaft (balanced nice) after installing gears. The vibration was alwasy there, you just never realized it.

As for the installation, you need to measure -- it's the onyl way to do it right and have it last. Hopefully you haven't ruined anything at this point. You can run a pattern on the gears or bring it right to a pro and have him do it -- that will give you some idea on how it's setup.

 

[AznStanger3v]

I thought about the driveshaft, but it was running smooth up to 120+ the day I pulled the stock (but worn) 3.08's out of it. I still think that my problem is that the pinion is too deep, simply because my brilliant father-in-law couldn't find my shim pack and since he happened to have a .045 shim laying around he had that pressed on my pinion. Granted the shim we pulled from the old pinion was .035 but that seemed excessive to me let alone adding 10 thousanths to it. I'm just tired of the guessing game, been it 4 times now, lol. Think I'll go to a professional soon. That or put a 9inch under I've done multiple third member ring and pinions.

thanks for the info guys

9 inch rear ends are overkill. NASCAR uses ford 9 inchers. Do you drive a NASCAR?

 

[Febulous]

9 inch rear ends are overkill. NASCAR uses ford 9 inchers. Do you drive a NASCAR?

NASCAR? I didn't say I needed a 9 inch smartass, just that I know how to set up a 9 inch and it would resolve my issue. BTW I don't think anyone can "drive a nascar".

Thanks for the help though. (wish I had thought to mark my driveshaft) < sarcasm, ask your english teacher about that

 

[Febulous]

Are you really just guessing and not measuring? Not a good system at all.

The vibration is most likely from the driveshaft, you'd probably get more "noise" out of a rear not setup correctly than vibration (don't ask how I know). The RPMS you'd be spinnign at about 120 are now what you spin at lower speeds, that's why most people go to an aluminum driveshaft (balanced nice) after installing gears. The vibration was alwasy there, you just never realized it.

As for the installation, you need to measure -- it's the onyl way to do it right and have it last. Hopefully you haven't ruined anything at this point. You can run a pattern on the gears or bring it right to a pro and have him do it -- that will give you some idea on how it's setup.

glad you pointed that out for me...maybe I should stop where I'm at and try to find a forum with some people that may know what they are doing. Surely they will be nice enough to provide me with some useful information. Tell ya what if you come across someone like that, send em my way huh?

 

[Febulous]

I believe that I found a website with the information I need to finish the job, however if there is anyone out there that has completed one of these installs and has some true insight that would be helpful, I would love to hear from you, otherwise please continue to read your magazines and listen to Daddy and his friends but don't try to give me hints on how to do a job that you've never done yourself.

 

[HoofnIt]

It sounds like you are off to a great start here on Stangnet. With comments like that you'll be lucky if anyone responds to your questions. By the way, welcome!

 

[mo_dingo]

NASCAR? I didn't say I needed a 9 inch smartass, just that I know how to set up a 9 inch and it would resolve my issue. BTW I don't think anyone can "drive a nascar".

Thanks for the help though. (wish I had thought to mark my driveshaft) < sarcasm, ask your english teacher about that

OMG. [size=+1]HE WAS JOKING[/size]

What a tool.

You are lucky I am bored and can't sleep.

You need to set the pinion depth 100% correctly, or else you can experience many kinds of problems.

You can't arbitrarily use a shim that you happen to have. If you are off by .005 if an inch, bad things can happen. Since you probably don't have a depth gauge, you need to use the following for proper PD.

GO HERE

Download the file in the first post. Unzip and open the installing gears based on shim thickness. It shows you how to measure your old pinion head/bearing/race and how to calculate the exact shim you will need.

If you still have problems, take it to a damn shop.
Scott

 

[95GTvert[bv12]]

I dont know the 9in is pretty cool it's the closest you can get to a quick change rear end...for it strengh it's very light...compared to the dana 60...and it fit's nicely between our rear tires....if you find a good 9in go for it...or ...go find a Aluminum dana 44 with 3.73's and just use that they are stonger then our 8.8 with 28 spline axles and are light...but no limited slip of the stock jeep apliacation