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| | | | Joined: Jun 2011 Posts: 14 New Guy | | New Guy Joined: Jun 2011 Posts: 14 | Hello All,
1971 C60 - 5 speed trans - 2 speed rear.
Hope you can help with this.
Must be a replacement tranny as the glove box tag says SP3152F but the hole in the floorboard is ROUGHLY enlarged 3-4" towards the rear to accept the shifter.
The switch is on the upper left.
It spins easily.
The retaining bolt is tight.
When it's in reverse I have no continuity on the switch poles.
Thoughts and / or part numbers??
TIA.
| | | | | Joined: Nov 2005 Posts: 6,100 'Bolter | | 'Bolter Joined: Nov 2005 Posts: 6,100 | Hy Chris_CoZi, according to my parts book the switch is p/n 3902194 for all standard transmissions 1968-72, hope that helps. | | | | | Joined: Jun 2011 Posts: 5,096 Crusing in the Passing Lane | | Crusing in the Passing Lane Joined: Jun 2011 Posts: 5,096 | Those are usually actuated by the reverse shift rail contacting a ball or plunger in the end of the switch. They must be tightened enough for the shift rail to make contact, otherwise they will not operate. Yours should be in close contact with the reverse shift rail. Take it out and make sure it functions properly, make sure it can be screwed in far enough to make contact.
Ed
'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires.
'47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle.
'54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed.
'55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.
| | | | | Joined: Jun 2011 Posts: 14 New Guy | | New Guy Joined: Jun 2011 Posts: 14 | The outer-contact portion of the switch spins freely. The threaded/bolt portion is tight to the case. I should assume this means the switch has failed? And is there any danger in removal ie a piece (ball?) left in the tranny? I can't see the switch area from below.
It seems like a deep socket should fit over it nicely.
I suppose I can have a magnet tool handy at removal.
Thoughts? | | | | | Joined: Nov 2005 Posts: 6,100 'Bolter | | 'Bolter Joined: Nov 2005 Posts: 6,100 | Hy Chris_CoZi,, the switch is a self contained unit, you should get all the pieces when you remove it, good luck. | | | | | Joined: Jun 2011 Posts: 14 New Guy | | New Guy Joined: Jun 2011 Posts: 14 | All -
Thanks for the assistance.
The part number worked for a reference.
The switch I purchased is a "NS18 Back Up Lamp Switch" and fits many transmissions.
Yes the switch was bad - no continuity.
Yes it came out in one piece - watch out for loose washers.
The new one screwed in and worked immediately.
;-) | | |
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