Stainless band clamp that keeps a GM front pump cover concentric to the body while you torque it, so the bushing and converter hub run true. Fits TH350/TH400/700R4/4L60E.
A converter that will not slide home on the bench, a front seal that weeps a month after the rebuild, or a pump bushing that comes out wiped on one side: on GM 700-R4, 4L60E, TH350 and TH400 units those problems very often trace back to a pump that was bolted together slightly off center. This lightweight stainless band clamps around the outside of the pump while you torque the cover to the body, so the bushing bore and the stator support finish up on the same centerline the converter hub needs.
The converter hub rides in the bushing pressed into the pump body, and the converter stator splines onto the stator support that sticks out of the pump cover. Those two parts are in different halves of the pump. The halves are located by dowels, but the dowels have clearance, and the cover can drift as the bolts are pulled down. When that happens the hub bushing and the stator support no longer share a center. The hub then rides hard against one side of the bushing, the front seal lip is pushed off center, and the converter can bind as it goes in.
The band takes that clearance out. With the halves assembled and the bolts started, you wrap it around the outer wall, snug the wing nut by hand so the cover and body sit flush all the way around, and torque the bolts while it holds them. Some builders follow up by sliding an old converter hub or alignment tool into the pump to feel for drag, but the band is what keeps the halves from moving in the first place.
Pull the converter and look at the hub. A shiny wear band on one side, or a hub that wobbles when you roll the converter on the bench, tells you the bushing and alignment need attention. Measure the pump bushing and stator support bushings once the pump is apart; our 4L60E pump rotor and bushing wear guide walks through what to check. If you are also chasing a lockup problem, the 4L60E common problems guide covers the TCC and valve body causes that are worth ruling out.
This band is sized for the smaller-diameter GM pumps: TH250, TH250C, TH350, TH350C, TH375, TH400, 3L80, 3L80-HD, 425, 475, 700-R4, 4L60, 4L60E and Powerglide. It is a bench tool, so it does not depend on vehicle year, only on the pump family. It is not for the 4L80E or later GM 6-speed and 8-speed pumps. If you are not sure what transmission is in your truck or car, check the ID tag or send us the year and VIN. The full lineup of parts for this unit is on our 4L60E parts page.
At 4.2 oz, it is the lightest of the alignment bands we carry and easy to keep in a rebuild tool roll.
| Material | Stainless steel band |
| Adjustment | Wing nut clamp for fast fit |
| Fits | GM TH250, TH250C, TH350, TH350C, TH375, TH400, 3L80, 3L80-HD, 425, 475, 700-R4, 4L60, 4L60E, PowerGlide |
| Use | Front pump cover-to-body alignment during assembly |
| Weight | 4.2 oz |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
If the leak is caused by the converter hub running off center in an off-center pump, yes. Aligning the halves keeps the bushing and seal bore concentric with the hub. Also check the hub for grooves and the bushing for wear, since a worn bushing leaks regardless of alignment.
It is listed for GM TH250, TH250C, TH350, TH350C, TH375, TH400, 3L80, 3L80-HD, 425, 475, 700-R4, 4L60, 4L60E and Powerglide pumps. It does not fit the 4L80E or newer GM 6-speed and 8-speed pumps.
The dowels give rough location, but there is clearance in them, and the cover can shift a few thousandths while you torque the bolts. The band clamps the outer diameters together so they cannot move.
Hand tight, just enough that the cover and body are flush all the way around the seam. The band is there to hold alignment, not to clamp the pump together; the bolts do that.
A front seal, pump to case gasket and O-ring at minimum, plus the pump body bushing and stator support bushings if they measure worn. Inspect the converter hub, and use Dexron VI on a 4L60E.
