Lowering Question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

modmach1 · 10-29-2004, 05:10 AM

My truck is lowered 4" with Belltech shackle kit
Well i took two weeks and the rear end said bang.. then i mounted a new one, and yesterday i heard some sounds in the rear end when i put it in Reverse. The hole car rocks.. So my question is: when dropped 4", must i then shorten my driveshaft`? It wasent easy mounting the drive shaft after changeing the rear end..

SCOTI · 10-29-2004, 07:56 AM

I have a flip kit + dropped shackles. I didn't alter my driveshaft length & haven't had any problems after almost 2yrs on the road. What shape are your u-joints in ?

bigblock73 · 10-29-2004, 08:19 AM

I have the Bell Tech 4" shackle/hanger kit...never experienced any problems, I had mine on the road three years before I tore it apart.

I am with Scoti...check the U-joints.

Slonaker · 10-29-2004, 09:13 AM

Quote:

Originally Posted by modmach1

It wasent easy mounting the drive shaft after changeing the rear end..

Maybe you just have the wrong driveshaft?

Slonaker

CLASSIC87' · 10-29-2004, 12:27 PM

I have had my springs dearch 4" inches, a 2" shackle, and I have just recently removed the "heavy half" spring for another 1" or so. Anyways.... I have not had any problems with the drive shaft being to long or making any unusual noises.

Anthony

88Jimmy4x4 · 10-29-2004, 01:45 PM

Check your u-bolts

loblazer · 10-29-2004, 03:32 PM

Check your pinion angle. Must not be more than 2 degree difference positive or negative or you will take out the u joints and/or the rear gears.
I have a 5" flip kit with C notch in my 2wd Blazer. Took out 2 sets of u joints before I realized the pinion angle was wrong.
Luckily I discovered the trans mount was crap and was throwing my angle off. When I replaced that with a new one, the angle was 1 degree. Over 4000 miles now with no problems.
Check your trans mount in the crossmember and see if it is at all worn down. If so, replace it and then check your angle with a protractor gauge. Any part store would have one.

If it is still off, you can get pinion shims from any chassis shop or 4x4 specialty shop. Come in 1 degree up to 6 degree sizes so you should be able to get dead on. Do not go to zero though, it must be 1 or 2 degree to give some flex on acceleration.

October TOM

Doug

piecesparts · 10-31-2004, 08:49 PM

Length of the driveshaft is important. If the driveline is to be centered in the transmission output shoft seal, then you may have to shorten it. I had to on a couple of trucks. I believe that your problem would be at the tranny before you would have problems with the rearend, if it was to long. The ouptput shaft would be leaking or the tube would be damaged before that heavy rearend would give any.

10-29-2004, 05:10 AM	#1
modmach1 Registered User Join Date: Sep 2004 Location: Norway Posts: 152	Lowering Question My truck is lowered 4" with Belltech shackle kit Well i took two weeks and the rear end said bang.. then i mounted a new one, and yesterday i heard some sounds in the rear end when i put it in Reverse. The hole car rocks.. So my question is: when dropped 4", must i then shorten my driveshaft`? It wasent easy mounting the drive shaft after changeing the rear end.. __________________ http://www.moldestuket.com 1971 Mustang Mach-1 429 CJ-R 1973 Mustang Mach-1 289 1975/71 Pontiac Firebird Formula 400 1978 Chevrolet C-10 Fleetside Longbed Scottsdale 1980 Pontiac Phoenix

10-29-2004, 07:56 AM	#2
SCOTI Registered User Join Date: Apr 2001 Location: DALLAS,TX Posts: 21,942	I have a flip kit + dropped shackles. I didn't alter my driveshaft length & haven't had any problems after almost 2yrs on the road. What shape are your u-joints in ? __________________ 67SWB-B.B.RetroRod 64SWB-Recycle 89CCDually-Driver/Tow Truck 99CCSWB Driver All Fleetsides @rattlecankustoms in IG Building a small, high rpm engine with the perfect bore, stroke and rod ratio is very impressive. It's like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar..... *Cubic inches is like Indiana Jones with a cheap pistol.*

10-29-2004, 08:19 AM	#3
bigblock73 yeller Join Date: Oct 2001 Location: Twin Cities Posts: 13,826	I have the Bell Tech 4" shackle/hanger kit...never experienced any problems, I had mine on the road three years before I tore it apart. I am with Scoti...check the U-joints. __________________ Jeff 73-87.com 73-87.com Facebook page 73-87 cab corner 6x9 speaker brackets for sale 67-72 cab corner speaker brackets for sale 47-54 cab corner speaker brackets for sale

10-29-2004, 01:45 PM	#6
88Jimmy4x4 Registered User Join Date: Oct 2003 Location: houston, texas Posts: 1,974	Check your u-bolts __________________ 2008 Silverado Z71 RCSB 1991 GMC Jimmy 4x4 1976 GMC Sierra C15 SWB

10-29-2004, 03:32 PM	#7
loblazer Senior Member Join Date: Mar 2004 Location: Fergus, Ontario Posts: 481	Check your pinion angle. Must not be more than 2 degree difference positive or negative or you will take out the u joints and/or the rear gears. I have a 5" flip kit with C notch in my 2wd Blazer. Took out 2 sets of u joints before I realized the pinion angle was wrong. Luckily I discovered the trans mount was crap and was throwing my angle off. When I replaced that with a new one, the angle was 1 degree. Over 4000 miles now with no problems. Check your trans mount in the crossmember and see if it is at all worn down. If so, replace it and then check your angle with a protractor gauge. Any part store would have one. If it is still off, you can get pinion shims from any chassis shop or 4x4 specialty shop. Come in 1 degree up to 6 degree sizes so you should be able to get dead on. Do not go to zero though, it must be 1 or 2 degree to give some flex on acceleration. October TOM Doug Last edited by loblazer; 10-29-2004 at 03:44 PM.

10-29-2004, 12:27 PM	#5
CLASSIC87' OL BLUU Join Date: Mar 2004 Location: WICHITA, KS. Posts: 1,065	I have had my springs dearch 4" inches, a 2" shackle, and I have just recently removed the "heavy half" spring for another 1" or so. Anyways.... I have not had any problems with the drive shaft being to long or making any unusual noises. Anthony

10-31-2004, 08:49 PM	#8
piecesparts Parts and more parts Join Date: Nov 2003 Location: Lebo, Kansas (middle of nowhere Posts: 6,821	Length of the driveshaft is important. If the driveline is to be centered in the transmission output shoft seal, then you may have to shorten it. I had to on a couple of trucks. I believe that your problem would be at the tranny before you would have problems with the rearend, if it was to long. The ouptput shaft would be leaking or the tube would be damaged before that heavy rearend would give any.



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