2wd lift and axle length

Feintmotion86 · Feb 15, 2022

Hey all...need your input. I just had a re-gear done on my 97 tahoe, and the shop ( just so happens to be a driveshaft shop) is wanting me to be aware that the driveshaft needs a certain amount of bite onto the spines of the trans, and that I'm outside of that spec. Makes sense, since the rear is lifted about 3-3.5". I consider it to be a relatively mild lift, as I know some of you have gone much higher than that. Any problems? Or perhaps is there a known limit to the rear lift before a longer driveshaft is in order?

Also to note...he was indicating that if they built me a longer custom driveshaft, that there would be a clearance issue with the crossmember. He claims that the diameter of the tubing would have to be bigger than stock and would contact the crossmember, so that some cutting would be needed.

SUBURBAN5 · Feb 15, 2022

Idk if it helps but I lifted my suburban with the rc 4" lift and my components are all stock. I've been wanting to get my driveshaft rebalanced and new u joints, but other then that nothing scrapes and nothing has indicated being too short......

Nad_Yvalhosert · Feb 15, 2022

I've got a 2wd 3/4 ton. 4.5" lift knuckles up front and regeared the rear ro 4.88. When I reinstalled the 14 bolt, I put on a set of 4" tapered blocks. The carrier bearing in the 2 piece driveshaft stayed in the OE location. The rear section pulled out 3/8" of the slip. That to me is inconsequential being that the entire spline section is over 4".

How big of a rear block are you installing? 3"? Tell the shop "Thanks for your concern. I'm good with the stock driveshaft."

Feintmotion86 · Feb 18, 2022

I have a rear add a leaf and a 1.5" block. I think its a total of about 3", 4" max.

I think they were just telling me as a safety precaution because they HAVE to tell me for liability reasons. I took a look myself though and like both of you mentioned, there seems to be plenty of meat left on the spline that its biting.

my guess is, 6" or more and you probably need a longer driveshaft (on 2wd). Thanks for the input guys.

OBS Oregon · Feb 18, 2022

I have a 96 C1500 silverado that had 3in blocks under the rear springs. Stock drive shaft. Didn't notice any issues...

A97obs · Jul 13, 2024

OBS Oregon said:
I have a 96 C1500 silverado that had 3in blocks under the rear springs. Stock drive shaft. Didn't notice any issues...

Interesting I found this thread as old as it is ...this doesn't seem to be an issue for one other person here... when it clearly in my case may be and it draws the yoke out of the tail shaft plenty ,
plenty enough to create a vibration.. and I'm sure everyone is using a tappered block

Notice the 2" that's out of the tail shaft and that's on
RC 4" TAPPERED lift blocks

You must be registered for see images attach

A97obs · Jul 13, 2024

Nad_Yvalhosert said:
I've got a 2wd 3/4 ton. 4.5" lift knuckles up front and regeared the rear ro 4.88. When I reinstalled the 14 bolt, I put on a set of 4" tapered blocks. The carrier bearing in the 2 piece driveshaft stayed in the OE location. The rear section pulled out 3/8"

So you have a extended cab 2wd with the 2 piece shaft and carrier setup ? and your 4" blocks allows your yokes to stay in place factory more less on the blocks ?
For me I have a solid one piece drive shaft on my 99 suburban and my 4" tappered blocks pull my yoke out of my 4l60e plenty enough to be an issue/

Nad_Yvalhosert · Jul 13, 2024

A97obs said:
So you have a extended cab 2wd with the 2 piece shaft and carrier setup ? and your 4" blocks allows your yokes to stay in place factory more less on the blocks ?
For me I have a solid one piece drive shaft on my 99 suburban and my 4" tappered blocks pull my yoke out of my 4l60e plenty enough to be an issue/

Wow. This post takes me back to a mod I've nearly forgotten.

Reg cab, long bed 2wd 4L80e. The transmission has a fixed yoke, and a 2 piece shaft. The front section stayed in place as OE designed. Meaning the rear shaft angle is greater than a 1-piece 131" or 141" truck
On mine, the slip yoke is at the carrier bearing and that's where the length only increased by 3/8".

That being said, I've lifted a 117.5" wheelbase K1500. I noted an undesirable driveshaft "pullout" from the t-case. About 1.25" like the pics posted by O.P. I solved it by a set of offset leaf pads.
Kinda like these:

J X2-BLO-OFFSET Lift Blocks 1/2" axle Offset DriveLine Fwd/Back 1" thick | eBay

<p>FREE SHIPPING TO USA 48 STATES<br>Product Questions call 1 800 842 8789 <br></p>.

www.ebay.com

These moved the shaft back in 3/4", and shortened my wheelbase to 116.5

2wd lift and axle length

Feintmotion86

Newbie

SUBURBAN5

I'm Awesome

Nad_Yvalhosert

I'm Awesome

Feintmotion86

Newbie

OBS Oregon

I'm Awesome

A97obs

I'm Awesome

A97obs

I'm Awesome

Nad_Yvalhosert

I'm Awesome

J X2-BLO-OFFSET Lift Blocks 1/2" axle Offset DriveLine Fwd/Back 1" thick | eBay

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