Im not exactly sure where to put this post but figured id put it here cuz i believe its suspension related. Well to start i have a 1986 K5 Blazer. Its got a 305 in it. Great running motor and everythings awesome. My problem is the truck has a 3 inch lift installed on it. I dont know exactly how long the input shaft is that goes into the transfer case. The transmission when you drive in 1st gear it makes a big pop going into second like it makes the whole truck jump. I was wondering if this is caused by the lift or is it transmission problems? If anyone knows please let me know how to fix it because i really need me truck running right.

 

3" suspension lift or body lift? I ask just for clarification. A body lift would not change your driveshaft angles nor length. A suspension lift should have corrections for pinion angles. How do the u-joint angles look? Does it look like there is a hard angle at either end of the driveshaft? I think even with up to a 4" lift, you do not have to do anything with the driveshafts, but if the pinion angles were not corrected, it could explain the problem.

 

its a 3 inch suspension lift. I bbought it from a guy dont ask me how or where he got a 3 inch suspension but he did. Its got blocks and add a leaf. Either way he never put any shims in the rear axle so thats at a hard angle so i guess fixing that could help. Also how much does a 4 inch lift normally run?

 

Depends on how you are going about getting it. Most people get a 4" lift in the rear by doing a shackle flip using any one of the commercially available kits. You could just get some wedges to correct the pinion angle. They are also available at a few different places. SummitRacing.com is one of them. You really need an angle finder to get the angle of the t-case output shaft and then compare it with the rear diff pinion shaft angle. They should be the same so you do not have any vibrations.

I am not convinced this is your problem though.. Just wanted to know if you could rule out the driveshaft angles. With the truck in the air, axles supported on jack stands, and the transfer case in neutral, when you rotate the driveshaft, do you feel any binding?

This does sound more like a transmission problem. Does it do this whenever you shift from 1st to 2nd regardless of the load (both terrain and throttle position)?

 

the truck does it when you really get into it. The truck has a shift kit so it shifts really hard from 1st to 2nd but it never does it any other time. I really just want to figure out the problem cuz its my daily driver and im worried the trannys gonna go up and ill really be screwed. The angles are the same even though the rear end isnt shimed to any degree. is this okay or should i get shims for the rear? Also where could i get one of the shackle flip kits?

 

also how far does the input shaft normally stick out of the transfer case?

 

DIY4x.com has the shackle flip kits. But you would want to remove whatever was put in my the previous owner.

If the angles look the same between the transfer case to driveshaft and the driveshaft to pinion shaft, then that probably is not your problem.