Th400
The B&M Adjustable Vacuum Modulator (Part# 20234) comes pre-adjusted for ‘normal’ shift points, but it is fully adjustable (see below), allowing you to customize the shift points (within a range of 2-4 mph). This unit is designed for use with select applications, including GM TH400 and TH350 transmissions.
FTI Performance TH400-4.5UB - FTI Performance TH400 Level 4.5 Transmissions Automatic Transmission, 3-Speed, Ultra-Bell Bellhousing, Reverse Shift Pattern, Full Manual Valve Body, GM, TH400, Each Part Number: FTI-TH400-45UB. Street/Strip and Drag Racing TH400’s Stage 1 TH400 – 450 HP/TQ capable. Our Stage 1 TH400 is a heavy duty rebuild with valve body and hydraulic improvements, rollerized rear thrust, heavy duty intermediate snap ring, and OEM pan. 450 HP/TQ capable but proven at much higher HP levels. Each TH400 Performance Transmission is built with in-house machining and is hand assembled to deliver unbeatable performance and durability. FTI TH400 Transmissions come in many configurations, from mild street to a 2000 HP 2 or 3-speed to meet your performance needs. Note: Speedometer drive gear and driven gear not included. The TH400 uses an electronic kick-down mechanism, which means that there will be an electric plug on it. The TH350 uses a mechanical linkage that attaches to the carburetor. Th350 has the vacuum modulator in the back, and the TH400 keeps it on the side. Using the pan bolt pattern is the easiest way to identify the TH400.
- Allows you to tailor shift points
- B&M Quality
- Comes pre-adjusted
- Fully adjustable
Please note: If you have a big camshaft and your engine does not make adequate vacuum, you will not be able to make the stock or B&M modulator work properly, usually resulting in late, hard shifts. A minimum of 12″ Hg engine vacuum is required for proper operation.
Installing the B&M Vacuum Modulator
Fits GM TH350 & TH400 Automatic Transmissions, Part# 20234
Adjusting Shift Points
You can adjust the modulator with a small screwdriver. Turn the adjustment screw clockwise to raise shift points and counter-clockwise to lower shift points.
Th400 Transmission Cooler Line Routing
Get the Kit
B&M Vacuum Modulator for GM TH350/TH400 Automatic Transmissions ~ Part # 20234 on Amazon
Th400 Torque Converter
Questions?
Need a product recommendation for your vehicle or application? Give B&M a call at (866) 464-6553
Chevy 4x4 Turbo 400 Transmission
Also of Interest:
Th400 Transmission Specs
| GM TH400 SPEEDOMETER PARTS | |||
Th400 speedometer Hold down fork | stainless steel | $6.00 | |
Th400 speedometer housing 34-39 tooth | billet aluminum | gm # 1362294 | $55.00 |
Th400 speedometer housing 40-45 tooth | billet aluminum | gm # 1362293 | $55.00 |
Th400 speedometer gear 34 tooth | gm # 9774413 | $10.00 | light green |
Th400 speedometer gear 35 tooth | gm # 9780387 | $10.00 | pink |
Th400 speedometer gear 36 tooth | gm # 1359270 | $10.00 | white |
Th400 speedometer gear 37 tooth | gm # 1359271 | $10.00 | red |
Th400 speedometer gear 38 tooth | gm # 1359272 | $10.00 | blue |
Th400 speedometer gear 39 tooth | gm # 1359273 | $10.00 | brown |
Th400 speedometer gear 40 tooth | gm # 1362048 | $10.00 | black |
Th400 speedometer gear 41 tooth | gm # 1362195 | $10.00 | yellow |
Th400 speedometer gear 42 tooth | gm # 1362049 | $10.00 | green |
Th400 speedometer gear 43 tooth | gm # 1362196 | $10.00 | purple |
Th400 speedometer gear 44 tooth | gm # 9780470 | $10.00 | gray |
Th400 speedometer gear 45 tooth | gm # 9775187 | $10.00 | light blue |
Th400 speedometer housing seal preferred | $3.00 | ||
Th400 speedometer housing o-ring seal | $1.00 | ||
Th400 10mm hold down bracket bolt and | $1.00 | ||
Th400 14 tooth speedometer drive gear | $25.00 | ||
Th400 15 tooth speedometer drive gear | gm # 8629547 | $25.00 | |
Th400 17 tooth speedometer drive gear | gm # 8629548 | $25.00 | |