1985 Buick Century Automatic Transmission Kits

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Keep Your 1985 Buick Century in Top Shape with a Quality Automatic Transmission Kit

When it comes to maintaining or upgrading your 1985 Buick Century, choosing high-quality parts is crucial for ensuring your vehicle stays in top shape, whether you’re tackling a repair or enhancing performance. At Advance Auto Parts, we know how important it is to find the right Automatic Transmission Kit for your Century. We currently carry a top Automatic Transmission Kit in stock that is built to last. Whether you’re replacing a damaged Automatic Transmission Kit or looking to upgrade, our selection for the 1985 Buick Century ensures you’ll find exactly what you need to keep your vehicle looking and performing its best.

Explore Related Parts

And while you’re here, don’t forget to check out related part categories like Torque Converter and Related Products and Transmission Cooler and Parts to complete your upgrade or repair project. At Advance Auto Parts, we’re proud to offer the parts and expertise to keep your 1985 Buick Century running smoothly and looking great.

Essential 1985 Buick Century Automatic Transmission Kits

ATP – ATP Automatic Transmission Shift Kit, JK-1 (Part No.JK-1)

ATP Automatic Transmission Shift Kit, JK-1

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$80.99
ATP Transmission Components are exact fit, no compromise replacement parts
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B & M – B & M Transmission Kit, Master Overhaul Kit For Th400, 21041 (Part No.21041)

B & M Transmission Kit, Master Overhaul Kit For Th400, 21041

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$478.99
These kits include all of the necessary components to rebuild your automatic transmission. OEM style gaskets included. Kits do not include overhaul instructions – please refer to factory shop manual for proper assembly procedures.
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B & M – B & M Shift Improver Kit For 65-87 Th400 Transmission, 20260 (Part No.20260)

B & M Shift Improver Kit For 65-87 Th400 Transmission, 20260

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$77.19
The B&M Shift Improver kits feature two options to recalibrating your 1965-1987 GM TH400, TH375 and TH475 automatic transmissions. First is the HEAVY DUTY set-up, giving you firm positive shifts without loss of driver comfort for improved performance in all street vehicles. This is a great option for performance street driving or towing. The second is our STREET/STRIP set-up. Be warned, this will deliver firm positive shifts you will feel, along with easily chirping the tires when shifting somewhat aggressively. This setting is recommend for high performance street/strip use, or for competitive events when you want the hardest, quickest shifts possible from a shift improver kit.
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B & M – B & M Transkit For 65-87 Th400 Transmission, 20229 (Part No.20229)

B & M Transkit For 65-87 Th400 Transmission, 20229

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$519.99
A B&M transmission in a box! Transform your automatic transmission into a full-tilt B&M performer! This is our ultimate transmission kit – it comes complete with full instructions on how to assemble your transmission to B&M specifications.
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B & M – B & M Shift Improver Kit For 68-81 Th-350 Transmission, 30262 (Part No.30262)

B & M Shift Improver Kit For 68-81 Th-350 Transmission, 30262

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$73.89
The B&M Shift Improver kits feature two options to recalibrating your 1968-1981 GM TH350 automatic transmissions. First is the HEAVY DUTY set-up, giving you firm positive shifts without loss of driver comfort for improved performance in all street vehicles. This is a great option for performance street driving or towing. The second is our STREET/STRIP set-up. Be warned, this will deliver firm positive shifts you will feel, along with easily chirping the tires when shifting somewhat aggressively. This setting is recommend for high performance street/strip use, or for competitive events when you want the hardest, quickest shifts possible from a shift improver kit. Note: Does not fit GM TH350C with lock-up. Use part# 30235 for TH350C transmissions.
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B & M – B & M Transpak For 68-81 Th 350 Transmission, 30228 (Part No.30228)

B & M Transpak For 68-81 Th 350 Transmission, 30228

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$172.99
The B&M Transpak is the next step up from the B&M Shift Improver kit. It has all the features in the Shift Improver kit, plus it provides additional driver manual control (GM TH-400, 350, Ford C-6 and Chrysler Torqueflite only). B&M Transpak kit for 1968-1981 GM TH350 automatic transmissions. Most stock automatic transmissions won’t downshift into low gear above 15 mph, and automatically upshift at a predetermined speed no matter what gear you’re in. With the Transpak, you can downshift at any speed, and you can hold the transmission in first gear to any speed that you want! This is an asset when you’ve got a modified engine, and you want additional RPMs, or you’re towing a trailer or driving heavy loads downhill. Stage 1. Heavy Duty is for street rods, normal passenger vehicles or other heavy duty use. Firmer shift feel but not harsh. Improves transmission performance and life dramatically without loss of comfort and offers normal automatic operation when in Drive. Stage 2 is for Hi-Performance street use. Essentially the same as Heavy Duty mode except shifts are much quicker. Retains full automatic features and standard shift points with selector in Drive. Notes: Does Not Fit GM TH350C transmissions.
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Most Popular Transmission Shift Kit for 1985 Buick Centuries

Enhance your 1985 Buick Century with this popular Transmission Shift Kit we have in stock, for $519.99.

B & M – B & M Transkit For 65-87 Th400 Transmission, 20229 (Part No.20229)

B & M Transkit For 65-87 Th400 Transmission, 20229

from

$519.99
A B&M transmission in a box! Transform your automatic transmission into a full-tilt B&M performer! This is our ultimate transmission kit – it comes complete with full instructions on how to assemble your transmission to B&M specifications.
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FAQs for 1985 Buick Century Automatic Transmission Kits

What’s the price range for 1985 Buick Century Automatic Transmission Kits?

We currently have just one Automatic Transmission Kits for the 1985 Buick Century in stock: B & M Transkit For 65-87 Th400 Transmission, 20229 and it costs $519.99.

Does Advance Auto Parts sell Automatic Transmission Kits for other Buick Century model years?

Yes, we carry Automatic Transmission Kits for 29 model years of Buick Centuries between 1973 and 2005. The following model years are the most popular for Automatic Transmission Kit purchases: 2005, 2004, 2003, 1997, 1996, 1995, 1994, 1993, and 1992.

Does Advance Auto Parts sell Automatic Transmission Kits for any other 1985 Buick models?

What types of Automatic Transmission Kits do you sell for my 1985 Buick Century?

We currently have just 1 Automatic Transmission Kit in stock for a 1985 Buick Century, and as of 8/2/26, it is a Transmission Shift Kit.

Can I get help with 1985 Buick Century Automatic Transmission Kit orders?

Contact our customer support team by chat or phone, through the help desk page, where you can find instant answers about Buick Automatic Transmission Kits and more.

What is your return policy for Buick Century Automatic Transmission Kits?

Advance Auto Parts keeps returns simple. For new Buick Century Automatic Transmission Kits and accessories, your online orders can be returned, in their original condition, within 45 days. For requirements, see the returns page.