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Torx Plus is the fastener system that ambushes people. It looks like Torx, it sits where you expect Torx, and a standard Torx bit will go into it and even turn it — right up until you apply real torque and round the head off. This is the reference page for knowing where it hides.
Torx vs Torx Plus in one table
| Standard Torx (T-series) | Torx Plus | |
|---|---|---|
| Marking | T10, T25, T50 (also TX) | 50IP officially; TP50 in tool catalogues |
| Lobes | 6, pointed and tapered | 6, squarer with flatter tips |
| Contact area | Baseline | Greater — higher torque, less wear |
| Introduced | 1967, Camcar Textron | ~1990, patent expired 2011 |
| Typical use | Everywhere, aftermarket and OEM | OEM assembly line hardware |
Compatibility, precisely: a standard Torx driver can drive a Torx Plus screw, but not to full torque — the fit is loose. A Torx Plus driver will not fit a standard Torx screw at all. That asymmetry is the whole story: the wrong tool works just well enough to fool you on the easy bolts and fails on the tight ones.
The reason OEMs use it: squarer lobes spread load across more of the recess, so an assembly line can torque harder without wearing out tooling. Great for the factory. Annoying for you in a driveway ten years later.
Where GM uses Torx Plus
Transmission bell housing bolts — TP50
The big one. 4L60E bell housing bolts are TP50 Torx Plus. This is where most people meet Torx Plus for the first time, usually badly, usually with the trans already on a jack. Similar hardware shows up across the 4L60E/4L65E generation.
If you are pulling one of these, this is the tool:
Lisle 81090 TP50 Torx Plus Bit Socket, 3/8″ drive →
Other GM hardware
Torx Plus turns up sporadically elsewhere on GM driveline and case fasteners. If a “Torx” bolt feels loose in the recess, stop and check the lobe shape before applying torque.
Where Ford uses Torx Plus
Lisle lists both of the following as Torx Plus applications for its 81000 series. Worth being precise: Lisle confirms the system, not the specific size, so check the actual fastener rather than assuming TP50.
Seat belt anchor bolts
Safety-critical hardware torqued high at the factory. If you are pulling seats, trim, or B-pillar panels, expect Torx Plus at the anchors.
Pickup bed mounting bolts
Bed removal jobs run straight into these. Add rust from a decade of road salt and a loose-fitting bit and you have a genuinely bad afternoon.
How to identify Torx Plus on the vehicle
- Look at the lobes. Squarer with flatter tips means Torx Plus. Pointed and tapered means standard Torx.
- Do the wobble test. Insert your standard Torx bit and try to rock it. Noticeable play in a size that should fit snugly is the tell.
- Know the job. GM trans bell housing, Ford seat belts, Ford bed bolts — treat as Torx Plus until proven otherwise.
Tooling up
- One size, one bit. If you have one specific job — almost always a 4L60E — buy the single TP50 socket. Done.
- Full set. The Lisle 81000 Torx Plus set covers a range of sizes if you do regular OEM driveline and interior work. The 81090 is the TP50 replacement bit out of that set.
Either way, get it on the shelf before the job starts. Nobody has ever been happy about discovering they need a Torx Plus bit halfway through a transmission pull.
Quick FAQ
Can I just use a standard Torx bit on Torx Plus?
It will turn at low torque. It will not hold at full torque, which is when you actually need it. On a seized bell housing bolt, don’t.
Can I grind a Torx bit to fit Torx Plus?
No. You would be removing the material that carries the load and making the fit worse. Buy the bit.
Is Torx Plus the same as security Torx?
No. Security Torx (TR-series, also called pin-in Torx) has a post in the centre of the head. Torx Plus is about lobe geometry and torque capacity, not tamper resistance. A tamper-resistant Torx Plus variant does exist — five lobes plus a centre post.
Will a TP50 work on a T50 bolt?
No. Torx Plus drivers will not fit standard Torx fasteners. Keep both.
What size is a 4L60E bell housing bolt?
TP50 Torx Plus (50IP), driven on 3/8″.
→ Lisle 81090 TP50 Torx Plus Bit Socket
Related
- Torx Plus size chart and identification guide
- Stripped a 4L60E bell housing bolt? Why your T50 failed
- Ford seat belt anchor bolts
- Ford truck bed bolt removal
- Lisle 81090 TP50 socket review
Image credits: Featured image “Torx screws” by Disturbx, licensed CC BY-SA 4.0, via Wikimedia Commons. Torx Plus internal screw head by Andrew Pertsev, CC0 / public domain.
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