is this gear rumor true?
- Thread starter Ted87GT
- Start date
willys1
Active Member
unless you have the gauge and tools to do it,You should get it done.You cant just take the old ones out,and put the new ones in.Its a pretty precise installation!!
795.0pacecar
lover of pudgy polygamists
willys1 said:
Yes you can, my dad and I have done it quite a few times, all we do is transfer over the old shims to the new gears and bolt everything back up, we have never had any problems, in fact, the one time my dad had his gears done by a shop they made noise.
If you dont know what your doing you should have it done by a shop or have someone who has done it before help you.
Backlash has to be just right everything has to be in phase just right or they will make noise and even break.
You really do have to know what you are doing to do it. I just overhauled my entire rear axle over the past couple months. New bearings all-around, new seals all-around, 3.55 gears, torsen differential, new brake line, rear disc brake conversion, sandblasted, primed, and painted axle black.
Now I will say that The stock pinion shim miked out to be .023" and when I used FRPP 3.55 gears to do the installation, I ended up going with .018" to make the perfect pinion depth. The tool makes it worlds easier to do and I highly recommend something that does the same thing if you cannot afford the tool. Also my stock backlash shims could not be totally reused. I believe I used the stock shim of .244 for the left side but I had to reduce the shim on the right from .240 (stock) to .220 in order to get the carrier bearing preload correct not to mention to fit. My pinion preload was perfect at 15 in/pounds, backlash perfect at .010" when spec is .008"-.015", final pattern was perfect and am awaiting to get the axle in which will be complimented by new everything out back in the suspension.
I heard the rumor as well before I started diving into the axle but I could not find the identifying marks to reference the base .030". There is a lot of precision measurements to do not to mention you need a good amount of tools to do it. Now to me it wasn't all that hard - just very time consuming. But however at the same time i'm also an auto technician. So take it for what it's worth.
Now I will say that The stock pinion shim miked out to be .023" and when I used FRPP 3.55 gears to do the installation, I ended up going with .018" to make the perfect pinion depth. The tool makes it worlds easier to do and I highly recommend something that does the same thing if you cannot afford the tool. Also my stock backlash shims could not be totally reused. I believe I used the stock shim of .244 for the left side but I had to reduce the shim on the right from .240 (stock) to .220 in order to get the carrier bearing preload correct not to mention to fit. My pinion preload was perfect at 15 in/pounds, backlash perfect at .010" when spec is .008"-.015", final pattern was perfect and am awaiting to get the axle in which will be complimented by new everything out back in the suspension.
I heard the rumor as well before I started diving into the axle but I could not find the identifying marks to reference the base .030". There is a lot of precision measurements to do not to mention you need a good amount of tools to do it. Now to me it wasn't all that hard - just very time consuming. But however at the same time i'm also an auto technician. So take it for what it's worth.
just because someone has done something haphazzardly (without measuring) does not mean it will work each time.
to do it right, one needs to check and understand the dynamics and make it precise - the tolerances are very tight. im amazed that machining tolerances on gears are as precise as they are, that blanket statements or experiences about not needing to measure, can be made.
it might be spot on, but one should measure everything to be sure. cool?
to do it right, one needs to check and understand the dynamics and make it precise - the tolerances are very tight. im amazed that machining tolerances on gears are as precise as they are, that blanket statements or experiences about not needing to measure, can be made.
it might be spot on, but one should measure everything to be sure. cool?
I couldn't agree more. It's foolish to just put something together and call it "good enough" without a second look. Something of this criteria is a precision operation and if not done right and slapped together, there will be a day when slapping something together will teach someone a lesson..............HISSIN50 said:
glad i made sense and someone agrees with me.87'GTstang said:
another situation that is similar is steel bearing retainers. people dont measure endplay on those either. just 'cause someone doesnt and it appears to work does not mean that it was 'spot on'.
89MustangGX
I have nothing productive to add!
87'GTstang said:
I also agree. Gears are kind of like magic. Everyone claims to know how it works, but the only people who seem to really know it all are nowhere to be found!
Anyway, you can have a buddy do them or just throw them in yourself and there's a chance they will work. I heard of a guy who used to put everything together and run a paper bag through the gears and if the bag didn't tear it was set right. Guess he was too cheap to even use gear marking compound.
It's not right unless you check all the measurements. There are just too many variables to guess or have companies make them all to fit right. Bring it to a Pro (not your buddy who bought some tools -- done that before) and have it done right. It's worth it, and you'll feel better in the end.
larrendeuce
Member
I have all the tools and parts to swap gears, except the gears. How do you measure the backlash with the dial indicator and magnetic pedestal? I have seen pictures but what am I measuring?
larrendeuce said:
If you've already got all the toys then there is a video that was put out by "Shade Tree Mechanic". you should be able to find it on the net. I have not seen this video but I've heard from others that it lays it all out pretty well from start to finish. May be a way to go if you can't find someone in the know, to show you how to do it.
Edit: I didn't find the Shade Tree video but did find this:
http://performanceunlimited.com/cobravalley_tools/gearvideo.html
Hope it helps
You are placing the dial indicator in-line with the ring gear with the tip of the dial indicator between the teeth. Basically what you are doing is rocking the ring gear back and forth to see basically how much play there is between the teeth. In other words, the tighter the ring and pinion mesh together, the less the backlash. The further the ring and pinion are apart, the greater the backlash. What you are measuring is the space between the peaks and valleys of the two by rocking the ring gear in it's natural position.larrendeuce said:
I already stated the spec for backlash on the 8.8" from memory so here it is again: .008"-.015"
795.0pacecar
lover of pudgy polygamists
Hey I never said to do it himself, I just said it could be done and I haven't had any problems doing it myself.
VG30DE
Founding Member
I've done a bunch of rear ends. 8.8's are damn easy to do. I've directly swapped the gears and carriers between a 91 lx and a 97 gt, I change the ring and pinion between my notch and my lincoln all the time leaving the same carriers in place, I did an 02GT with a the stock shim and didnt have to change anything, 2 95 GT's with stock shims, and a few GM's and other cars. I always check the pattern with grease and check the backlash by hand and not one has ever broken or whined. Make sure theres not a ton of play between the ring and pinion, and it the carrier was tight and fine before then you wont have a problem with anything because there was no problem before and the only change is the ring and pinion spacing. IMO, try it yourself and save a whole bunch of labor money and if you cant get the best of it, put the stock **** back in and take it to a shop.
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