Eleven stepped drivers sized for every GM 4L80E case, pump, stator and drum bushing, so new bushings go in square and at the correct depth.
Rebuilding a 4L80E out of a Silverado or Sierra 2500, a Suburban 2500 or an Express van and wondering how to get a dozen new bushings in without a pile of mismatched sockets? This 11-piece driver kit is cut for the GM 4L80E and the 4L80E-based 4L85E. Each driver is stepped to suit a specific bushing, with a pilot that centers in the bushing bore and a shoulder that pushes on the bushing edge, so it goes in square and stays round. The drivers are matched to the common 4L80E bushing numbers 46626B, 46627, 46627A, 46627B, 46629, 46630, 46631, 46632A, 46633A, 46634A, 46635B and 46640.
In a 4L80E, bushings do two jobs. They support the shafts and drums, and they act as controlled leaks around the oil passages that feed the converter, lube and clutch circuits. The tighter the clearance, the more of that oil goes where it is supposed to. Wear opens the gap, pressure bleeds off, and the result is the low pressure and lockup complaints that high-mileage work trucks are known for. The case bushing has its own problem: Sonnax sells a no-walk-out version because the stock part can migrate out of its bore and let the output shaft move. Sonnax lists that case bushing bore at 2.129 inch and the front stator support bushing bore at 1.244 inch, which gives you a feel for how precise these fits are.
A bushing that is tapped in with whatever socket is close to size usually goes in cocked or with a rolled edge. Its inside diameter is then wrong before the truck ever moves, and it can seize on the shaft or wear oval quickly. A matched driver spreads the load around the full edge of the bushing, which is the simplest way to avoid that.
Not every pressure loss is bushings. A failing pressure control solenoid or a worn valve body bore will also drop pressure, so test the electrical side and read the codes first. Our 4L80E common problems and fixes guide sorts out pressure, lockup and heat failures, and 4L80E Silverado 2500 common problems covers what towing does to these units. Once the case is apart, slide each shaft into its bushing and feel for rock. Any bushing that is scored, tapered or lets the shaft wobble gets replaced.
The set is sized for the GM 4L80E and 4L85E, which share bushing sizes. It is a tool set, so it fits by bushing size rather than model year: it works the same on a 1991 unit as on a 2009 van transmission. Bushings are not included, so order them with your overhaul parts and check each number against your service manual. The drivers suit the parts listed above; if you are using an aftermarket bushing with a different size, measure it before you start. For the rest of the parts for your build, start at our 4L80E parts page.
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Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
The drivers are matched to bushing numbers 46626B, 46627, 46627A, 46627B, 46629, 46630, 46631, 46632A, 46633A, 46634A, 46635B and 46640, which are the common 4L80E and 4L85E bushings.
No. The kit is the 11 drivers only. Order your bushings separately and match each one to its driver.
Yes. Steady pressure from a press or controlled hammer blows both work. Stop when the bushing reaches the depth in your service manual.
Yes. Several 4L80E bushings sit next to the converter and lube circuits. When they wear, oil leaks past them and the converter clutch can slip enough for the computer to set a slip code. Rule out the solenoids and the valve body as well.
It is sized for the 4L80E and 4L85E. Some TH400 sizes overlap, but measure any bushing outside the listed numbers before using a driver on it.
