Author Topic: Removal of front drive shaft  (Read 27080 times)

Offline qboy

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Removal of front drive shaft
« on: December 17, 2007, 07:20:33 PM »
I want to change the gear ratio so I can cruise on the freeway better and I don't want to have to pay to have the front changed when I don't use the 4 wheel drive.   I heard I could remove the front drive shaft if I just want to change the rear gears.   Is this true?   What's involved in doing this?
1975 K15 GMC 1/2 ton SWB 4x4 383 (stroked 350), turbo 350 tranny

Offline DirtyLittleSecret

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Re: Removal of front drive shaft
« Reply #1 on: December 17, 2007, 09:25:03 PM »
Removing about 8 bolts...Just make certain that you NEVER EVER USE 4WD.
78 K20: fresh 350, SM465, NP205, 4" Pro Comp, & working hard!
65 Jeep J300: 13.5:1 383, TH400, NP205, mostly NOS. 
88 Toylet LandCruiser FJ62: LT1, 4L60e, 3" OME, Aussies.
06 VW TDi: DD@72mpg.

Offline nova801428

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Re: Removal of front drive shaft
« Reply #2 on: December 18, 2007, 12:34:28 AM »
What if you need the 4wd?  Why not just get bigger tires? 
1975 Chevy k20 6" lift 35" BFG MT's True Dual Exhausts Radical Cam

1980 GMC 2500 Parts Truck

Offline JJSZABO

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Re: Removal of front drive shaft
« Reply #3 on: December 18, 2007, 07:52:39 AM »
If the tires were the same all around then there would still be a mismatch in gear ratios from front to rear.  Now if you put different size tires on the front to correct the ratio mismatch then......

When I did my Ford Expedition gears (from 3.31 to 4.10) I did both the front and rear.  It's the only way to do it correctly, in my opinion.

Jeff
Jeff

86 Chevy C-10
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Ex father and son project (son lost interest)

Son regained interest when truck was almost completed

Offline Blazin

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Re: Removal of front drive shaft
« Reply #4 on: December 18, 2007, 09:10:43 AM »
This will hurt the resale value of the truck, as the next owner will have to correct the rear gear back to what its suposed to be. Why don't you get a 2 wheel drive truck? Or better yet get a Toyota Carolla, or Honda Accord if you want milage?
Some people are like Slinkies. Not really good for anything, but they still bring a smile to your face when you push them down a flight of stairs

Offline 1976Scottsdale

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Re: Removal of front drive shaft
« Reply #5 on: December 18, 2007, 10:04:23 PM »
That depends also on whether or not you have an unconverted NP203 or a part-time 4x4 setup in the first place.  If you are not part time, then you will be asking for trouble and sentencing you T-case to death.  I know as I am getting ready to rebuild my NP203 after the previous owner did this and ruined the case.  I can actually hear it chatter over the noise of the engine when I drive it.

Offline qboy

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Re: Removal of front drive shaft
« Reply #6 on: December 18, 2007, 10:58:40 PM »
Mine is not full time.   I've got the floor mounted lever to put it in 4wheel high 4wheel low.   I never use the 4wheel drive.   I believe I've got 3.73 gears.

My options are:

1) keep it as is (high revs on the freeway)
2) paying to have front and rear gears changed (expensive)
3) getting a 700r4 tranny (expensive)
4) removing the front driveshaft and changing the rear gears (not sure if this is dangerous or could harm any components)
1975 K15 GMC 1/2 ton SWB 4x4 383 (stroked 350), turbo 350 tranny

Offline 1976Scottsdale

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Re: Removal of front drive shaft
« Reply #7 on: December 18, 2007, 11:29:46 PM »
How high you revving on the highway?  Yeah, I guess you could do that.  I'd just get matching axles from your donor truck.  But you could just swap the rear.  I did it once, but I ended up needing the 4x4 shortly after.

Offline DirtyLittleSecret

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Re: Removal of front drive shaft
« Reply #8 on: December 18, 2007, 11:30:18 PM »
Honestly, go get a honda/toyota car for mpg.  You wont be changing your end mpg by dropping the front driveline, but you will probably reduce the truck's value by maybe half.  Not to mention reducing your functionability.  Running two sizes of tyres is stupid, and cause just as much damage as not running them.
78 K20: fresh 350, SM465, NP205, 4" Pro Comp, & working hard!
65 Jeep J300: 13.5:1 383, TH400, NP205, mostly NOS. 
88 Toylet LandCruiser FJ62: LT1, 4L60e, 3" OME, Aussies.
06 VW TDi: DD@72mpg.

Offline Fordeatinz71

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Re: Removal of front drive shaft
« Reply #9 on: December 19, 2007, 12:55:57 AM »
to answer your question...no, you won't hurt anything by running sans front driveshaft.  i've seen people do it for years.  it doesn't matter.  heck, you can LEAVE IT IN, just don't lock your hubs in or engage 4wd and you'll be fine.  just do yourself and your truck and its future owner a favor...fix the rear now, save up and fix the front later...it's not THAT expensive...
1991 Chevy Silverado K1500 ECSB, 350, 700R4 w/shift kit, 3.42's, exhaust work...
1983 GMC Sierra K1500 SWB-sold :(

Offline jonkmbll89

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Re: Removal of front drive shaft
« Reply #10 on: December 19, 2007, 08:34:51 PM »
Mine is not full time.   I've got the floor mounted lever to put it in 4wheel high 4wheel low.   I never use the 4wheel drive.   I believe I've got 3.73 gears.

My options are:

1) keep it as is (high revs on the freeway)
2) paying to have front and rear gears changed (expensive)
3) getting a 700r4 tranny (expensive)
4) removing the front driveshaft and changing the rear gears (not sure if this is dangerous or could harm any components)

Your floor mounted lever is 4wheel high and 4wheel low only or do you have 4H, 4L, N, & 2H?
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Offline qboy

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Re: Removal of front drive shaft
« Reply #11 on: December 19, 2007, 09:20:34 PM »
Mine is not full time.   I've got the floor mounted lever to put it in 4wheel high 4wheel low.   I never use the 4wheel drive.   I believe I've got 3.73 gears.

My options are:

1) keep it as is (high revs on the freeway)
2) paying to have front and rear gears changed (expensive)
3) getting a 700r4 tranny (expensive)
4) removing the front driveshaft and changing the rear gears (not sure if this is dangerous or could harm any components)

Your floor mounted lever is 4wheel high and 4wheel low only or do you have 4H, 4L, N, & 2H?
It's got 4H, 4L, N, & 2H.    I even jacked up the rear and put it gear to make sure the front driveshaft wasn't spinning.     I'm not interested in improving my mpg, it's just geared seriously low and it's spinning the motor at too high an rpm to cruise even at 65.    I might have to just bite the bullet and get a 700r4.    I just got a quote of $2,500 for the trans and converter installed.
1975 K15 GMC 1/2 ton SWB 4x4 383 (stroked 350), turbo 350 tranny

Offline nova801428

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Re: Removal of front drive shaft
« Reply #12 on: December 19, 2007, 09:27:27 PM »
Pretty sure you have all-time 4wd.  I have it too on my 75.  A transfer case shifter on the floor, and no locking hubs.  The front is always spinning.  Unless you convert to hubs then get the oiling kit for the transfer case then I don't suggest doing it.  The transfer case if oiled by the front end spinning (tires, axle, drive shaft) and if it doesn't get enough oiling...then it is toast. 
1975 Chevy k20 6" lift 35" BFG MT's True Dual Exhausts Radical Cam

1980 GMC 2500 Parts Truck

Offline Fordeatinz71

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Re: Removal of front drive shaft
« Reply #13 on: December 19, 2007, 09:30:17 PM »
you should do yourself a favor and learn to do the work yourself.  it's not that hard and you can save a LOT of money.  just by buying the new transmission and TC (vs. rebuilding the tranny yourself, that gets hard and you'd need a 700R4 core) from a place like www.bowtieoverdrives.com would only run you about $1,500-1,800 or so...that's almost $1,000 saved.  but i will say that $2,500 isn't a bad price to have a new 700R4/TC retrofitted into a truck that never had one...

no, if he has 2Hi at all, it is a PART-TIME t-case.  full-time was available but it wasn't the only option in '75.  he got lucky and doesn't have that crap. 
1991 Chevy Silverado K1500 ECSB, 350, 700R4 w/shift kit, 3.42's, exhaust work...
1983 GMC Sierra K1500 SWB-sold :(

Offline werewolfx13

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Re: Removal of front drive shaft
« Reply #14 on: December 19, 2007, 09:37:50 PM »
That seems awfully high to me..a 700r4 is about as easy to rebuild as a th350 (from watching somone do the r4 and having done a couple 350s myself), I'd go buy a $100 blown 700r4 from a junk yard and do it yourself.
Chris
'83 Chevy c10 Silverado SWB
'76 Chevy k20 LWB 6.5'x8' Flatbed
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