That is the max speed at which you can engage the CDL, not drive with it.
I have driven for more than 200 miles (all at once)at expressway speeds on snow covered roads with mine engaged with no ill effects.

 

that changes everything.

 

i agree i call it "best practice" to have your driveline balanced with like parts all around.

 

I got my TW shafts because Disco Mike recommended them and because they were about half the price of new shafts thru the LR stealership. My front shaft was cracked and felt like the truck was falling apart at like 35+mph so I had to do something fast and Tom came through for me and sent over night, and was still way under LR pricing.

Also when I bought mine I told Tom that I was going to lift the truck 3in (at least) and he told me that he would build them accordingly.

At or above 75mph they start to vibrate but i rarely go that fast. When I have time to sit around the shop some night while they pull them off and do it, I am going to have them balanced.

Overall I am happy with TW and his shafts.

 

Update: I got a 2nd driveshaft from Tom Woods, and still had vibration at 75+ mph.

Tom graciously agreed to return the 2nd shaft, too, and refund my money (even pay for shipping). That's one stand-up operation, and would still highly recommend them to anyone who doesnt frequently drive 70+ mph.

NOTE: Tom Woods will not accept driveshaft returns after 30 days, so you better check your vibration right after the install.

I think I'm going to go with the Todd Co reman driveshaft:
http://store.toddcosuspensions.com/larodiiifrdr.html

I'm going to be a freaking expert at swapping driveshafts.

 

Where are you located? I'll rebuild if for you for a heck of a lot less that $300.

 

Spike, I saw this and thought I would suggest you clear up the wording. Sounds like you are suggesting the can engage the CDL up to 45 MPH and that will gernade the t/case.
How about they can drive with it engaged up to 45 MPH when already engaged.
I have run mine at the ice races last year at over 60 with no problems.

 

nashville

 

The owners handbook clearly states that the diff-lock can be engaged at any speed, provided there is no wheel slippage when you engage it and you are traveling in a straight line. If wheels are slipping it says to let off the accelerator before engaging it.

If you're interested, PM me and we can see what we can work out. 2 day shipping for a DII front propshaft would be about $17.