Transmission Ground Wire

[scubachris]

Eureka! After having two mechanics tell me that the ground wire from my transmission to the body was intact, I finally climbed under my car and found out it wasn't even there. So I have a new clutch cable on order and need to hook up a ground wire. How do I know what gauge wire to use?

[divace73]

Eureka! After having two mechanics tell me that the ground wire from my transmission to the body was intact, I finally climbed under my car and found out it wasn't even there. So I have a new clutch cable on order and need to hook up a ground wire. How do I know what gauge wire to use?

the thicker the better, I think the original is 1 gauge?? It should be as a minimum just as thick as the power supply line

[aj81spider]

I'm not sure if Australian wire gauges are different, but in the US 1 AWG is 0.29 inches in diameter. That will be fairly difficult to attach and will be difficult to route/bend.

I believe what was on my car (a 74) was 12 AWG connecting the transmission to the body. That has a current capacity of 30 amps with 90 C insulation.

The bigger the better is good advice, but you run into practical limitations making the connections and bending the wires as you get too big.

[divace73]

i just looked on Wikipedia and said 1 gauge was around 7mm, I couldn't really recall but I do remember it was fairly thick and around 5-7mm???
https://en.wikipedia.org/wiki/American_wire_gauge

[aj81spider]

7 mm is right. That's about 0.3 inches. About 3.5 times as thick as 12 AWG.

That will be very thick wire. Hard to bend and you will need special heavy duty crimping tools to attach connectors to it.

[scubachris]

Thanks everyone your help. I will go to the electrical supply story tomorrow and get that wire. I am so stoked not to have to deal with this anymore

[spider2081]

A AWG #12 wire is too small. A AWG # 6 wire is about what was stock. The original ground on my 1981 attached to the bell housing below the starter through one of the flywheel cover bolts. The replacement is installed under one of the lower starter bolta and one of the steering box mounting bolts. It is very important that the terminals be properly crimped to this wire

[scubachris]

Can I install the clutch cable and then drive it to get the wire to ground it?

[v6spider]

You can buy premade battery cables that have loops on both ends. I'd use that.. Drill a hole through the firewall or floor plan and put a bolt clear through with a lock nut holding the loop end to the spot where you drilled. Make sure and grind the paint off where loop makes contact with the shell. Corrosion protection would also be a wise choice. Bolt the other end on with one of the transmission bolts or a good sized one on the block.. Clean contacts there too..

Cheers!
Rob

[scubachris]

Can I install the clutch cable and then drive it to get the wire to ground it?

That's a great idea

[DieselSpider]

Transmission and engine ground straps are generally made with a woven cable and are available at most parts stores for about $6 as universal items with the ends already attached with one or both ends having a star lug on it:

http://shop.advanceautoparts.com/p/atp- ... fragment-2

[v6spider]

Transmission and engine ground straps are generally made with a woven cable and are available at most parts stores for about $6 as universal items with the ends already attached with one or both ends having a star lug on it:

http://shop.advanceautoparts.com/p/atp- ... fragment-2

Just know that that particular grounding strap won't work for those spiders with the battery in the trunk.. Needs to be at least 4gauge wire for those models .. And it will barely work with those that have the battery in front.. That strap is made for cars that the negative cable from the battery is directly Mount to the engine.. Most Spiders the negative cable mounts to the body..

Rob

[DieselSpider]

Transmission and engine ground straps are generally made with a woven cable and are available at most parts stores for about $6 as universal items with the ends already attached with one or both ends having a star lug on it:

http://shop.advanceautoparts.com/p/atp- ... fragment-2

Just know that that particular grounding strap won't work for those spiders with the battery in the trunk.. Needs to be at least 4gauge wire for those models .. And it will barely work with those that have the battery in front.. That strap is made for cars that the negative cable from the battery is directly Mount to the engine.. Most Spiders the negative cable mounts to the body..

Rob

One on each side is what I would do and not have to deal with the more expensive and hard to work with cables. For the same money you can also get the thicker 15" engine grounding straps too. The point is that the cables are out there already made up and at reasonable prices.

[bradartigue]

Grounding straps are cheap and plentiful, buy two of them, one long enough to go from an engine mount bolt to the fenderwall (bolt it to the same place as the coil) - assuming you don't already have one. Get short one to go from the transmission (transmission bell housing cover bolt) to the firewall.

[v6spider]

This is what I'm talking about.. Only a few bucks more.. And you only need one.. Not two.. And your starter will thank you.



Cheers!
Rob