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Question for vms4evr!

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FordNoMore!

Guest
During a recent post concerning the gear change out from 2.59 to 3.54,you mentioned 3 parts needed for the speedometer to read correctly,,10456089 speed sensor 3 series,8642620 drive dear 15 tooth grey,25513050 driven gear 43 tooth purple, are these GM part numbers,is it a pain to get the drive gear in,looks to me like a project,Got a price today from my driveline shop for the gear change out,$925,alot of work is needed just by looking under the car,geez,not an easy job!Thanx for the info,very helpful.:beer
 

vms4evr

Well-known member
Joined
Jul 18, 2001
Messages
466
Location
Durham, NC
Corvette
2002 Flat Black Z06
Yes those are GM part numbers. You should be able to get them easily at your local dealer or order from GM direct.
The speed sensor install just goes in the side of the tranny and is not a big deal. The drive and driven gear require you to take off the tail housing. Considering you'll have the rear end out and the drive shaft off it is not a big deal. I let the guy who did my rear gears do the whole job. While they have it all apart it takes no time at all to do the speedo gears. It won't make much impact on the labor. Should take them 15min.
Graham
 
F

FordNoMore!

Guest
Ok thnx for the info, much appreciated.:beer
 
F

FordNoMore!

Guest
One mor queation for ya vms4evr,do them GM numbers match up fopr the 700 tranny as well as the 4L60,according to my stamping on the tranny I have a M code, 4L60 tranny, thanx again:beer
 

vms4evr

Well-known member
Joined
Jul 18, 2001
Messages
466
Location
Durham, NC
Corvette
2002 Flat Black Z06
I can't say for sure that the 700R4 and 4L60 use the same parts but they should. What I found out when I got the cross reference for speedo gears was that you are actually taking speedo gears (drive/driven) from a manual transmission. Because an auto trans car was never offered with 3.54 or 3.75 gears.
GM used the same speedo gear configuration as I understand it in all C4s. All you are doing is getting the right tooth count on both gears to get the speedometer to read correctly.
You should check to make sure that with a 3.75 you don't need a slightly different tooth count to make it accurate.
My speedo reads within maybe 2mph accurate with the combo I have. They would probably be perfect with a 3.45 gear.
If the person doing your gears does it a lot then he should know exactly what speedo gears you need. If not I can check.
Graham
 
F

FordNoMore!

Guest
Im confused, because everyone Ive talked to says the 4L60 didnt come out till 93, but my stamping is definetly a M for 4L60,so Im wondering if I got a fluke or a rare install,according to the date code it was made the 93 rd day of 92 so it would not be a late model yr,hmmmmmmm,anyway, I will go with the 3.54s,I appreciate all the help from ya folks:beer,if I have any problems I will hollar.
 

vms4evr

Well-known member
Joined
Jul 18, 2001
Messages
466
Location
Durham, NC
Corvette
2002 Flat Black Z06
If you're going with the 3.54 gears then just get the parts I listed. If they don't fit in your car I'll be really surprised. Even though you say you have a 4L60 I'll bet the tail housing is the same as a 700R4 and the speedo gears will be fine. Same for the VSS module. Expect your speedo to be within 2mph. If you want I can send you a spreadsheet that shows exactly what speed/rpm you get with 3.54 gears. Just email me.
Graham
 

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