6 INCH LIFT/208 RATTLE NEED HELP

[extremeblazer]

A customer just came to the shop with a 1987 Blazer that he installed a 6 inch Pro comp lift. The Blazer was being upgraded to a 12 bolt and 3:73 gears at the shop. After installing the lift the truck makes a load rattle almost grind noise from the rear when decelerating. All u-joints are new and angles are not bad. The Blazer has minimal drive shaft vibration when on the gas and the noise dosen't come with a vibration. The noise was the same with the original 3:08 10 bolt and the new 3:73 12 bolt. I think the slip shaft is to far out of the 208 transfer case and when not loaded is rattling around from loss of support. I have never installed a lift this high in a Blazer and not changed the transfercase to a 205. And I have never had this problem with lifts this high with a fixed yoke transfer case. Would a fixed yoke conversion solve this problem or a longer driveshaft help. Please post your fixes, before I spend the customers money on exspensive parts that may not work.

 

[BMR]

I had a similar problem with an 85 (700r/208) and a BDS 5.5 lift. My problem was the top two bolts that connect the T-case to the tranny. They where missing.(Long story). I'm not sure if that's what you are looking for but worth a shot.

 

[Rebel88]

I had a similar problem with mine. No lift, stock height and all that. It was a very loud rattle that happened when decelerating and sitting still. I found out it was that transfer case skidplate that comes off the transfer case crossmember. The bolts that held it to the crossmember were loose and it rattled like hell.

Might want to check that out too.

Later

Have you driven OVER a Ford lately?

 

[BOWTIE]

After installing an 8' 'lift on my blazer I had the same problem. It was the slip yoke as you explained. What I did was I added a C.V. type slip yoke when I had the drive shaft lenghtend. This took care of the rattle along with the vibrations I had.

Hope this helps.

Ric

MY K-5 DOESN'T LEAK... IT JUST MARKS ITS TERRITORY.

 

[DSLBLAZER]

My 83 blazer did the same thing. The sound was only heard when I was coasting. When I hit the gas it would go away. It was louder at faster speeds. I had a longer driveshaft made and it still did it. I put a 14 bolt in, and the sound is gone. I had a 12 bolt 4.56 gears and a lockright. Many people told me the lockright would cause this. My friend now has the 12 bolt and I am waiting to see if he has the same problems.

Keven