July 6, 2020

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Front gear ratio

THIS FORUM IS FOR ANY QUESTIONS ON THE 7.25" IFS FRONT DIFF, CV HALF SHAFTS AND FRONT DRIVE SHAFT.

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Scooter77
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I am merely driving my van
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Front gear ratio

Post by Scooter77 » Sat Jun 03, 2017 5:21 pm

How can i find out what gear ratio is in my front axle. Chevy astro AWD 2001.
I changed the rear axle , which has a 342 gear. As I was test driving it, as soon as it shifted into drive I heard a clunk and the right front end pulled towards the ground. I'm thinking I have mismatched gear ratios. Please help!

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Herbie
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Re: Front gear ratio

Post by Herbie » Sat Jun 03, 2017 11:26 pm

Scooter77 wrote:How can i find out what gear ratio is in my front axle. Chevy astro AWD 2001.
I changed the rear axle , which has a 342 gear. As I was test driving it, as soon as it shifted into drive I heard a clunk and the right front end pulled towards the ground. I'm thinking I have mismatched gear ratios. Please help!
Well, if the front axle is original, you can determine the ratio by looking at the RPO codes. Look for a white sticker with a set of 3-digit letter/number codes. I think on your year it's in the passenger door jamb. You can decode the values using this table.

When you say you "changed the rear axle", like, did you swap out the whole assembly or the guts? Did you change it TO 3.42, or FROM 3.42? I ask because if you have a 2001 AWD, you're likely to have 3.42 gears (GU6). I think there were a few 3.73s out there (GT4), but they were more rare. Everybody with big tires wants the 4.10 (GT5), but I've never seen that in a late-model van, which is why so many of us go aftermarket.
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2003 Astro AWD Astrolander/ZMB - GTRV Top Transplant, 4" OLV Lift, NP233 T-case, evolving interior
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Mmusicman
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Re: Front gear ratio

Post by Mmusicman » Sun Jun 04, 2017 2:04 pm

And to state the obvious regarding AWD vans:

YOU CAN NOT MISMATCH FRONT & REAR GEAR RATIOS OR TIRES!

If the gears are mismatched... STOP driving the van immediately!
A mismatch will cause permanent damage!

Temporarily and immediately remove the AWD fuse!
This will unlock the transfer case so you can at least move the van around... but even unlocked there is still some friction that can cause further damage to the transfer case clutches.
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2000 Chevy Astro LS AWD | 31" LT265/70R17 Tires | 8" LIFT | 10" TOTAL
92 Chevy Astro Shorty | V8-350
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