1978 K10 auto to 4 spd manual swap

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squaredeal91

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1991 SB
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5.9 Cummins 12 valve
Question time: I have a feeling ill be shortening another driveshaft because the one that came out is too short. My question is how to properly measure the amount of slip yoke inside and out.
 

squaredeal91

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this afternoon I started putting the inside back together. Put in the empty transfer case so I could finish shift linkage and got it adjusted for all its gears and its looking Decent now. At least I'm moving forwards. Its been over 100° today too.
 

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74Blaze

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My question is how to properly measure the amount of slip yoke inside and out.


I sent my driveshafts to Fort Wayne Clutch & Driveline to have them lengthened. They told what measurements to take and used that to figure the proper length.
 

Ricko1966

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c20
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I always just search my junk or go to the bone yard get something too long. Drive shafts aren't rocket science they don't have to be from the same kind of vehicle just the right length and yokes that will work. If I don't find something tge right length I buy a little too long and shorten them or have them shortened. It's a cheap way to get a driveshaft. Shortening is way easier so cheaper if you are having it done than retubing for length.
 

squaredeal91

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1991 SB
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K30
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5.9 Cummins 12 valve
I always just search my junk or go to the bone yard get something too long. Drive shafts aren't rocket science they don't have to be from the same kind of vehicle just the right length and yokes that will work. If I don't find something tge right length I buy a little too long and shorten them or have them shortened. It's a cheap way to get a driveshaft. Shortening is way easier so cheaper if you are having it done than retubing for length.
Im planning to do just this as I have several options. I've probably shortened a dozen driveshafts but its been a dozen years ago lol. My question is how to measure length. I made the last one it had in there. I just forgot how. I can probably do some more research.
 

squaredeal91

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I woke up last night thinking about my shifter mounting. I wasn't satisfied with how the mounting for T-case shifter went so... today I redid it.
Cut out a plate of 1/8" and drilled and tapped the holes for 1/4-28 bolts and welded top and bottom middle bolts for studs to go through from underneath. I sealed it with permatex and I think it came out pretty good, Definitely strong and should last. Now I need to clean up the boot and stuff. I couldn't get the shifter off to do so before
 

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Ricko1966

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Im planning to do just this as I have several options. I've probably shortened a dozen driveshafts but its been a dozen years ago lol. My question is how to measure length. I made the last one it had in there. I just forgot how. I can probably do some more research.
With the vehicle on the ground,weight on the wheels,ujoint mounting hardware on the differential yokes. Put your transfer case yokes in place,with room for them to push in when the suspension compresses, measure center to center of the ujoints,that's your new drive shaft length. Be sure weight is on the wheels when you measure.
 

squaredeal91

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This morning i started on the Transfer case and now its done. All new seals and some new bearings/bushings and 32 shaft.
Ready to go in the truck now. Everything is smooth and all gears shift good. Getting super close now. Unfortunately I have other projects to do so I will have to continue on later.
 

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squaredeal91

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Getting very close now. Transfer case installed. Filled up transmission. Filled transfer case. Finished under dash wiring from removing the column. Started it for first time since i started project Found the oil leak. (Oil pressure gauge line) ill fix in the morning.
If it wasn't for the oil leak i probably woulda put a 5 gallon bucket in there! Not much left but to put the seat back in and check a few things and I'm on my first test drive.
Oh and somehow the driveline fits pretty good. I couldn't believe it lol.
Its out maybe 3/4- 1" from where it was previously.
Lift has another car on it so ill have to wait till then to get final pictures of it all done.
 

squaredeal91

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1991 SB
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5.9 Cummins 12 valve
This morning I Fixed oil leak and cleaned floor Mats and blew off seat and put it in. Inside is pretty clean. Test drove great!! Everything seems to work good. I still can't believe about the driveshaft lol. Has good power as expected. I could probably rock 3.54s if I wanted but its all good. Looks and feels like its always been a manual. Clutch pedal isn't too hard either. Very successful!
Ill finalize this thread another day with pictures of everything. Thank you for all the support everyone.
 

idahovette

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See dude, (you know)I told ya it wasn't his FIRST rodeo!!!!! :big_banana_Dance:
 

squaredeal91

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I think im done with manual conversion project.
Wasn't satisfied with the t-case shift linkage. It worked but It was pretty far off. I tried cheating with the original one by installing it incorrectly i got 1/2" closer but not acceptable. I found this one from a 97 dodge 2500 thats adjustable. I heated and bent then painted blue. It works perfectly and is very smooth. It shares the same size pin as stock so I drilled a hole in the groove to use a cutter pin in it.
 

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Last edited:

squaredeal91

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Truck Year
1991 SB
Truck Model
K30
Engine Size
5.9 Cummins 12 valve
Changed both engine mounts and that made a vibration difference lol.
Redid the side covers because they were seeping a little. Finished cleaning and painting transmission. Installed the t-case vent tube. Refilled transmission. Test drove and leak free now.
 

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