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620 & FS5W71B (5 speed)


Charlie69

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Thank you Mike. I have FSM for 1976 620 and the 5 speed was not available according to the manual in 1976. Friend just bought a 1978 620 with a 4 speed & wants to change it out to a 5 speed. I know of 3 77 620 in wrecking yards here in Phoenix. So I will be checking them in the morning for a 5speed for him. Where is the FS5W71B numbers located on the transmission. 2 of the trucks do not have door handles any more and the windows are up. I prefer not to break a window so I will crawl under to make sure if it is a FS5W71B transmission. :D

 

Mike just wondering if you would be so kind as to do a write up on the manual transmissions with pictures and pin it in the drive train section like you did for the automatics.

 

You are a great source of info and I do not want to keep asking general knowledge (your general knowledge not mine) questions.

 

I have searched for your input on manual transmission threads but was unable to locate this info.

 

Thank you again Mike.

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There's nothing much on the truck that indicates 4 or 5 speed. If you can find the model identification on some paper work (maybe the door tag???) It looks like this: KHLG 620 KTUV it will indicate if it was equipped with a five speed at the factory. (could have been swapped) Anyway the first letter after the 620..... if an F it's a 5 speed, K is automatic.If a T this means floor shift and the F or K space was blank indicating a 4 speed. Confused? lol? Just look for an F after the 620.

 

Only way to be absolutely sure is to look at the top of the tail stock just forward of the shifter. Maybe pull the shift boot off or climb under it.

 

The 4 speed has a small rectangular plate with 6 bolts holding it on and a breather cap. It looks like this:

 

CopyofF4W71Bfrom75620001LargeLarge.jpg

 

The five speed does not have this:

 

79KC5spd.jpg

 

If this is too difficult to get at there is one other thing you may be ale to see.

 

This is the location of the reverse lights switch on the 5 speed. As you can see there are two locations available for it that can be drilled and tapped. The 5 speed is in the forward location.

 

revswB5.jpg

 

 

Here is an older 4 speed case that has been converted for use as a 5 speed. You can see where the reverse switch was located and plugged.

 

RevSwitch.jpg

 

 

 

 

As for a tutorial on transmission IDs I've been working on something with okayfine of the Realm. It's a bit 510 related but mostly how to ID a tranny prospect. Some good and bad points about them. What cars they come out of. Stuff like that.

.

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  • 2 weeks later...

Hey Mike,

Looking at the 2nd pictures you posted in this thread, of the 5spd... There are 3 electrical switches on it. One must be for reverse, what are the other 2 for? I noticed on my 79 620 there are at least 2 switches.

 

Thanks,

Dale - AZ

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79KC5spd.jpg

 

If I remember right this was a '79 620 5spd. Has 4 switches.

 

The very back one on the upper left is the neutral switch.

The bottom left just to the rear of the adapter plate is the overdrive (5th) gear switch.

The one slightly higher and just forward of the adapter plate is the top (4th) gear switch

The most forward one (and also on the 5th/rev shift rod as the overdrive switch) is the reverse switch.

 

The first three switches are emissions related.

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  • 12 years later...

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