Finally changing to 4:10 gears......any other tips, tricks or recommedations?

[HAWAIIZR-1]

Okay, I am finally getting to my differential and gears and looking for any thoughts of what else to do while I am under there. I am going to use the factory service manual procedures and drop the entire unit in my garage myself.

So far, I have:

- the complete kit with bearings, ring and pinion etc. that I will have a local shop r/r with stock unit

- speedo correction gears from Marc Haibeck

- C Beam plates

I will buy:

poly bushings and synthetic gear oil/w posi additive

Is there any thing I should look for other than the wear of tear of related items while I am under there or any recommendations from the experienced folks. This is my first time touching the differential, but I think I have all the tools needed for this job. My clutch is stock but fairly new so I'm not going to touch it yet. The 90 Z has 53K on it and the clutch only about 5K.

Thanks in advance and Happy New Year!

[Jagdpanzer]

Be sure your bearing kit also includes the side yoke bearings and seals. A lot of kits don't. While doing mine I converted the carrier caps from 1/2" bolts over to 1/2' ARP studs. Here are the ARP Part Numbers:
4 x Stud - AR4.060-LB
4 x Hex Nut - 200-8607
4 x Washer - 200-8514
To order you have to call ARP Order Desk & Technical Support: 800.826.3045

http://i540.photobucket.com/albums/gg333/pwasinger/080217124.jpg

You might also have a drain plug installed like in this pic while you have the case at the shop. Makes it a lot easier to service next time.

http://i540.photobucket.com/albums/gg333/pwasinger/080217041.jpg

In case you are interested here is a pic showing the stock 3.45 ring and pinion next to a Viper 4.10 set and a Yukon 4.10 set.
The Viper gear set is quite a bit more substantial.

http://i540.photobucket.com/albums/gg333/pwasinger/080217022.jpg

[jonszr1]

i would replace the 1/2 shaft u joints with the super spicer . bill b has the part number . just good ins also ck rear bearings

[Jagdpanzer]

Denny's Driveshafts has 1350 kit for C4 aluminum half shafts:

http://www.dennysdriveshaft.com/p422_corvette_aluminum_axle_half_shaft_1350_series _rebuild_kit.html

http://www.dennysdriveshaft.com/img/products/1225033934_CorvetteAluminumaxlehalfshaft1350Series RebuildKit_Cor.jpg

[HAWAIIZR-1]

Thanks a lot, I really appreciate the input and recommendations. I'll definitely look into these; I might as well do it right the first time. :handshak:

[HAWAIIZR-1]

Be sure your bearing kit also includes the side yoke bearings and seals. A lot of kits don't. While doing mine I converted the carrier caps from 1/2" bolts over to 1/2' ARP studs. Here are the ARP Part Numbers:
4 x Stud - AR4.060-LB
4 x Hex Nut - 200-8607
4 x Washer - 200-8514
To order you have to call ARP Order Desk & Technical Support: 800.826.3045

http://i540.photobucket.com/albums/gg333/pwasinger/080217124.jpg

You might also have a drain plug installed like in this pic while you have the case at the shop. Makes it a lot easier to service next time.

http://i540.photobucket.com/albums/gg333/pwasinger/080217041.jpg

In case you are interested here is a pic showing the stock 3.45 ring and pinion next to a Viper 4.10 set and a Yukon 4.10 set.
The Viper gear set is quite a bit more substantial.

http://i540.photobucket.com/albums/gg333/pwasinger/080217022.jpg



I really appreciate the information and pictures; truly awesome and just like David said about getting your advice. I sent you an email.

[HAWAIIZR-1]

Be sure your bearing kit also includes the side yoke bearings and seals. A lot of kits don't.
In case you are interested here is a pic showing the stock 3.45 ring and pinion next to a Viper 4.10 set and a Yukon 4.10 set.
The Viper gear set is quite a bit more substantial.

Jagdpanzer,

Thanks again and I guess you might have heard from ZZZZZR1 (David) that I have Yukon gears and this kit:

http://www.yukongear.com/ProductDetails.aspx?ProdID=2050

I guess I might have to consider getting some Viper gears?

I do have the drain plug kit from Corvette Clinic too; at the time I thought I was just going to install it and not change the gears.

[Jagdpanzer]

Craig,
You can get the side yoke bearings and seals here:

http://ratech.stores.yahoo.net/coax84d44.html

[HAWAIIZR-1]

Craig,
You can get the side yoke bearings and seals here:

http://ratech.stores.yahoo.net/coax84d44.html

Phil,

I really appreciate all your help and thought since I had a "Master Overhaul Kit" I was good to go. Thanks for the referral for the Viper gears too. Thanks for helping me do this right.

Big Mahalo and Aloha,

[James93LT1]

Craig,

You need help in dropping your rear end, let me know. Dropped mine a few times already.

James

[xlr8nflorida]

I suggest having a spare set of tires for when you burn up your first set :cool:

[HAWAIIZR-1]

Craig,

You need help in dropping your rear end, let me know. Dropped mine a few times already.

James

James,

Big mahalo; that is an awesome offer and I might have to take you up on it. I'll get with you offline and discuss. Looks like you have an awesome machine you have built and looking forward to speaking with you.

[HAWAIIZR-1]

I suggest having a spare set of tires for when you burn up your first set :cool:

Thanks, everyone says that about going with the gear change. I'm glad I do have a spare set. :cheers:

[Jagdpanzer]

Craig,
To make sure the studs go far enough in the case you may have to use a 1/2"-13 bottoming tap to deepen the threads.

http://www.victornet.com/productimages/812.jpg

[xlr8nflorida]

Thanks, everyone says that about going with the gear change. I'm glad I do have a spare set. :cheers:
:cheers:

[HAWAIIZR-1]

Craig,
To make sure the studs go far enough in the case you may have to use a 1/2"-13 bottoming tap to deepen the threads.

http://www.victornet.com/productimages/812.jpg

Phil,

Thanks again for all the tips.

[Gunny]

Craig,
Sounds like you've got it all together, including some good help. If you've got access to a lift, that is probably best. When I dropped the rear on a C4 I had no lift, but placed the car on ramps/jack stands high enough to work under. My neighbor provided a motorcycle/ATV jack (similar to a transmission jack) and it made all the difference. Good luck on those new gears. I'm just about to pull the trigger on some 4.10s for mine.
George

[-=Jeff=-]

In case you are interested here is a pic showing the stock 3.45 ring and pinion next to a Viper 4.10 set and a Yukon 4.10 set.
The Viper gear set is quite a bit more substantial.

http://i540.photobucket.com/albums/gg333/pwasinger/080217022.jpg

is it Left to right: Stock, Viper and Yukon?

[Jagdpanzer]

is it Left to right: Stock, Viper and Yukon?

Yes, left to right: Stock, Viper and Yukon

[HAWAIIZR-1]

Craig,
Sounds like you've got it all together, including some good help. If you've got access to a lift, that is probably best. When I dropped the rear on a C4 I had no lift, but placed the car on ramps/jack stands high enough to work under. My neighbor provided a motorcycle/ATV jack (similar to a transmission jack) and it made all the difference. Good luck on those new gears. I'm just about to pull the trigger on some 4.10s for mine.
George

Hey George,

Good hearing from you and thanks for your hard work with Membership. I really wish I had a lift as it really suck doing all the work under the Z on your back.....especially at our age. I really was thinking about getting one of those jacks or a trans jack since I do all the work myself. I don't think I want to bench press a ZF tranny either when I do my clutch and flywheel. I'm going to give the Yukon gears a chance since I have already spent too much on this Z; go for the Viper gears as suggested. If I move back to Fort Gordon I'll be sure to get in touch with you. Thanks for your thoughts.

[Gunny]

Hey Craig,

If you're still active duty, you need to get serious about getting someone to assign you about a week of TDY in Bowling Green around the 2nd or 3rd week of May. Or if you should get TDY to Gordon at the same time I'll loan you a spare for a road trip to BG (have to flip you for a Z or a C5, that's all I got).

Hawaii is rapidly rising on my bucket list of places to go ... haven't visited in over 30 years (was actually there for one week TDY) and my wife has never seen Hawaii, so we're doing some serious planning for sometime in the next 12-18 months. We would be tourists who are also visiting a former co-worker who retired there, but would definitely hook up with you for some local food/drink.

Good luck with the gears ... and definitely get one of those tranny/ATV lifts ... really makes a difference.

George

[HAWAIIZR-1]

Hey Craig,

If you're still active duty, you need to get serious about getting someone to assign you about a week of TDY in Bowling Green around the 2nd or 3rd week of May. Or if you should get TDY to Gordon at the same time I'll loan you a spare for a road trip to BG (have to flip you for a Z or a C5, that's all I got).

Hawaii is rapidly rising on my bucket list of places to go ... haven't visited in over 30 years (was actually there for one week TDY) and my wife has never seen Hawaii, so we're doing some serious planning for sometime in the next 12-18 months. We would be tourists who are also visiting a former co-worker who retired there, but would definitely hook up with you for some local food/drink.

Good luck with the gears ... and definitely get one of those tranny/ATV lifts ... really makes a difference.

George

Hey George,

I'm on the fence to retire and not sure if I will stay here. As you know $650K buys you an average, if that home and with the equity I have I can buy an awesome home in other place for cash....so I might take the $ and run. I thought about going to BG again and thanks for the offer; you make it so tempting.

Please do visit with your lovely wife and we'll be sure to show you a great time and help our with tours and nice places to go to. Your Southern hospitality was the best for a stranger like me when I was in your neck of the woods and I won't forget it. I have all the stuff coming that Phil recommended and Bill the ZF Doc was so kind to help me with doing the speedo gears. Yes, I have to get one of those jack; thanks for the recommedation. We'll touch base off line and thanks for the hard work with the membership.

Aloha and look forward to seeing you again,

Craig:cheers:

[HAWAIIZR-1]

Well, only a year later (man, am I slow) to the day and I finally got this almost done.

Thank you everyone for all the help with tips and tricks and especially JAMES93LT1 for coming over several times and helping with the posi rebuild and all the other tech advice; I owe you big time.

Thanks Phil for all your advice/emails and I bottom tapped for the studs and also have my drain plug installed (with magnetic plug). The case has been cleaned up as well as and ready for detailing. Decided to do same with the stirling silver POR-15 to case as I did with the batwing and yoke ends black POR-15. I decided to detail everything including the spring and will also buy the longer bolts to drop the rear about an inch.

Next week everything goes to a local shop to install the 4:10s, replace the seals, bearings, etc. I decided to just stay with the Yukons and hope it will hold up well.

:cheers:

[tf95ZR1]

Its been said before, but you will LOVE how the 4:10's
wake up the car. Definitely a worth while mod. Let us
know after your first drive.......:cheers:

[flyin ryan]

Its been said before, but you will LOVE how the 4:10's
wake up the car. Definitely a worth while mod. Let us
know after your first drive.......:cheers:I agree with Ted, stock or modified, dollar for dollar, best money you will spend, (& most fun :)). Makes the car so much more fun to drive in every gear, should have almost been manditory from the factory, minus the gas saver political B.S. car manufacturers have to go through.

[GOLDCYLON]

I agree with Ted, stock or modified, dollar for dollar, best money you will spend, (& most fun :)). Makes the car so much more fun to drive in every gear, should have almost been manditory from the factory, minus the gas saver political B.S. car manufacturers have to go through.

Have you done this to all your ZEDS Ryan? Ive been thinking about this one. Love the drain plug idea. Is the 4:10 too agressive for a daily driver? (I cant beleive I just asked that lol). Damn this car is a disease lol. I need to ask Phil if hes done this one yet as well

[tomtom72]

Have you done this to all your ZEDS Ryan? Ive been thinking about this one. Love the drain plug idea. Is the 4:10 too agressive for a daily driver? (I cant beleive I just asked that lol). Damn this car is a disease lol. I need to ask Phil if hes done this one yet as well

:redface: Warning: typical noob Q about to be asked!

I understand the quicker trip up in rpms idea, but doesn't that make our first gear all that much more useless? Also, my guess is it will be easier to blow the tires off in 1st? Obviously, I don't think I "get it" with this swap.

Where I live & drive ( NYC/Metro suburbs ) I don't even use 6th any more, heck sometimes I never get to 5th. I know my gas mileage sucks; I have a Cobalt for that! I understand that the 10's make 6th more usable, but then you loose it at the other end. I guess I'm the only one that feels 1st is useless in the stock configuration?

Confession: My 72 LT-1 had a 2.20 1st gear ( all '72 C. R. M/T sb vettes had this no matter M21 or M22 ), combined w/ 3.55 gear = 10 mph per 1,000 rpms in 1st gear. Therefore in 1st, 60 mph = 6k rpms; 70 mph = 7k rpms. That was really useful for those really slow & tight 1st gear corners. I kind of enjoyed that. This car has no valve train garbage, it would be really sweet to have a bit more "room" in 1st, no? I guess I'm out in left field one this one, right? Sorry for seeming to be so obtuse. :redface:

:cheers:

[HAWAIIZR-1]

Thanks for the replies and I can't wait to try them out; it will be a few months as I am still waiting on the top half porting work and some other bottom half components. I am sure it will awesome with all the other upgrades being done at the same time. With the aluminum flywheel too it is going to scream to redline and cause traction problem as well as create a tricky launch.

Tom,

I think the gearing upgrade is not for everyone and I hope I don't decide I want to change back (I doubt it in my case). I read all the pros and cons about it and several folks changed back to 3:45 as you have probably read too. I would think it would be for you in the city area as it is for me on this island where I feel I need the lower gears. I don't even get the chance to use 5th gear either; I think it will be fun though and looking forward to it.

[Dynomite]

You might also have a drain plug installed like in this pic while you have the case at the shop. Makes it a lot easier to service next time.

http://i540.photobucket.com/albums/gg333/pwasinger/080217041.jpg



I am thinking I will install a drain plug without splitting the differential case :D

I will then flush out any debris after drilling and tapping and install a magnetic plug :thumbsup:

That will be easier than using a pump ;)

That does not look like a 91' case? I have to know exactly where to drill on a 91' case to get the low spot on the flange. I think if I drill just to the South of that lower middle bolt (Z facing west) I will be fine :sign10:

[Dynomite]

Have you done this to all your ZEDS Ryan? Ive been thinking about this one. Love the drain plug idea. Is the 4:10 too agressive for a daily driver? (I cant beleive I just asked that lol). Damn this car is a disease lol. I need to ask Phil if hes done this one yet as well
If the daily driver is the car.....I dunno....if the daily driver is you....definitely not :D
This car is not a disease but it is definitely habitual :sign10:

[jonszr1]

personally i think that either 392 or 410 gears makes the car easier to drive in stop and go traffic.less shifting and i can go as low as 22 miles an hr in 4th gear. fuel milage on the freeway doesnt seem to go down at all. at least on my cars

[flyin ryan]

Have you done this to all your ZEDS Ryan? Ive been thinking about this one. Love the drain plug idea. Is the 4:10 too agressive for a daily driver? (I cant beleive I just asked that lol). Damn this car is a disease lol. I need to ask Phil if hes done this one yet as wellNo, not all me Zed's Daryll, just my 90 that I was playing with last summer. I don't want to get into playing with my 93 &/95's just because... but after doing the swap in my 90 & it working Ssooo good, I am ½ considering doing all my cars:o. For myself, after driving a car with 4.10's getting into one with the stock ratio is simply borderline pathetic, sorry to say. It makes the car that much more fun to drive, I never found any downside...for me. Actually get use the shifter/trans. with the 4.10's. Friend of mine that doesn't come on forums very much, craigs427, has a 95 AB Zee #103, well after he drove my car with the gear change, he immediatly had me order a set for him. I knew ahead of time the gears would help out, I pick out gear ratio's for customers every week, but after I installed them, had no idea how much...in every way, I would enjoy driving the car so much more ;). I feel like an advertisment, but honestly for me it's the best, cheapest, easiest performance gain a person can do. A PROM upgrade is a good bang for the buck too, to be fair, but has nowhere near the performance upside of the gears, although it does help in other ares IE: fans, idle calibration etc., O.K., getting off my soap-box now, I LOVE the gears :worship:, end of story.

[HAWAIIZR-1]

Ryan and Brad,

Thanks for sharing your experience and confirming what I am looking forward to with the gear change...........I can't wait :dancing

[Dynomite]

With the 4.10s does the pinion have one less tooth and the ring gear the same number of teeth?

So...how many teeth on the original 3.45 ring gear and pinion and how many teeth on the 4.10 ring gear and pinion?

[Scrrem]

With the 4.10s does the pinion have one less tooth and the ring gear the same number of teeth?

So...how many teeth on the original 3.45 ring gear and pinion and how many teeth on the 4.10 ring gear and pinion?

Just did my 4.10's and they were marked:

3.45 38 Ring 11 Piinion
4.10 40 Ring 10 Pinion

Rich

[HIZNHRZ]

fuel milage on the freeway doesnt seem to go down at all. at least on my cars


This is the second ZR-1 I've had upgraded to 4:10 gears. I agree drivability is improved in most all measurable performance areas. One of my Z's was basically stock, the other has a 500Hp top end package. Hammering through 1st gear in the modified car still takes some getting used to.

The stock Z with 4:10 gears was all upside including highway gas mileage (typically 25-26 MPG if I kept my foot out of it). With a stock car and 4:10 gears, I did not notice any significant difference in gas mileage. With the modified ZR-1, however, it does not matter how much I baby it, I haven't seen better than 20-21 MPG on a trip.

[jonszr1]

is your 500 hp pkg just inj housings and plenum, or is it heads too???? my callaway 475 snat zr1 with 392s gets about 24.5 27 on the freeway during a long run.if it has been a while since you have changed you 02 sensors or have a scanner,ck to see if one or both are a little lazy. .mine got lazy and mileage went in the sh$tter. changed them and poof milage back to normal .

[HIZNHRZ]

is your 500 hp pkg just inj housings and plenum, or is it heads too???? my callaway 475 snat zr1 with 392s gets about 24.5 27 on the freeway during a long run.if it has been a while since you have changed you 02 sensors or have a scanner,ck to see if one or both are a little lazy. .mine got lazy and mileage went in the sh$tter. changed them and poof milage back to normal .

The Haibeck package includes heads. I would be great if the lost mileage was from something like the O2 sensors. I'll check it out. MPG certainly is not the reason for having a car like the ZR-1. It sure was something else, however, to have a 20 year old car generating the kind of power of a ZR-1 and still get 25 MPG on the highway.

Thanks for the tip!

[HAWAIIZR-1]

Thanks to Phil and others for all the advice to build my diff and get the 4:10 upgrade. Thanks for James LT1 for helping me out with his special tools and rebuilding the posi unit. I'm on my way now and will detail this housing before assembly to the batwing.

http://i78.photobucket.com/albums/j86/hawaiizr1/DSC01821.jpg

[flyin ryan]

Awesome buddy, you'll love em' :thumbsup:

[Scrrem]

Looks great Craig!!!
Rich

[GrayZ]

Craig, it is very difficult to get a diaper inside the bat wing once you have installed it, make sure you polish it to a gleen beforehand. You are gonna wonder why you have waited so long to install them once they are in..:mrgreen:

R U goin to BG this year? U are welcome to fly to st louis and ride down with me.

[HAWAIIZR-1]

Thanks guys.

Keith,

I am trying to get to BG this year and appears my leave will be approved but coming in on the day of and did not have enough time to stay longer. I appreciate the offer but I might be renting a car or bum a ride from Nashville if available.

As for the diaper and batwing I thought about it and too much trouble so it was painted instead. You know that you are the diaper King with the polished LT5 so stop trying to pass the crown to me already; you won a long time ago.:cheers:.........wait, I forgot about Ricky:mrgreen:. Take care and hope to see you there.

[HAWAIIZR-1]

http://i78.photobucket.com/albums/j86/hawaiizr1/DSC01827.jpg

After a good wash with POR-15 Marine clean, 1 part to 1 part water, rinse, then metal prep for 30 minutes and dried.

http://i78.photobucket.com/albums/j86/hawaiizr1/DSC01840.jpg

Taped up and intial coat of POR-15 Stirling Silver to match the batwing, the yokes will be POR-15 chassis black then assembled.

[Hammer]

Everything looks fantastic Craig.

[RICKYRJ1]

Looks Great! We need to get that Z State Side. We need another crazy anal brother who has the sickness :-D When I get mine back I have some special tweaks in mind to finish it off. See ya in BG

[HAWAIIZR-1]

Thanks for the comments John and Ricky. It appears I will definitely see you folks in BG and will see if my leave got the final approvals needed today. Yes, I need to get to the upper 48 as all the shipping for everything is killing me and want to enjoy some nice WOT drives with the gears and all the work to the motor. Take care! :handshak: