driveshaft modification when lowering? 5.3 and 4l65e
 

Hey Guys-

I have another thread going regarding my recent failure on a truck that I just bought. Short story was that it appears that the rear gear oil was left out when the restoration was done. Rearend failed, locked up and broke the sunshell in the trans.

I have now had the rearend rebuilt, purchased a new trans, and now the shop is saying that the driveshaft is too long. When you guys have done your swaps and then lowered your truck, did it require a shortened driveshaft? I am just trying to filter through possible shop BS to see if this really needs to be done. It drove just fine prior, no vibrations, etc.

Re: driveshaft modification when lowering? 5.3 and 4l65e
 

It would have a lot to do with where you located the engine/trans front to back when it was installed..if they say its to long that could be easily checked by you to verify...if they are reputable I would go with what they say if you cant check it yourself..on mine its 1" from bottomed out with the suspension loaded..you don't want it to bottom out when the suspension moves thru its cycle.

Re: driveshaft modification when lowering? 5.3 and 4l65e
 

I went from a 350/400 to the 4.8/4l60e and had my ds rebuilt to the specs per the ds peeps needed. Lowering the truck shouldnt make much difference in length i wouldnt think.

Just picked it up. Looks to me like there's enough play, but I could be wrong. There's definitely something off though, there's a clear whining/grinding when slowing down. I'll have to dig in to determine if it's truly the DS.
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Re: driveshaft modification when lowering? 5.3 and 4l65e
 

Not sure what year your working on but if its a coil spring rear its easy enough to remove the rear springs and see if at full compression the shaft has enough travel to not bottom out in the transmission

Re: driveshaft modification when lowering? 5.3 and 4l65e
 

Well you had the diff and trans rebuilt..its easy to check driveshaft length..if on the ground chock wheels very good or put on lift..put trans in nuetral..remove u-joint caps at the differential..slide driveshaft into trans tailhousing to check for clearance..should be at least a inch..when they rebuilt the rear did they put all new stuff in or reuse some original parts? Below is a link to west coast diff with a troubleshooting page..if you can put it on a lift that will help narrow down where the noise is coming from by running it in gear with the wheels off the ground..or could be coming from the trans???..if you paid them to fix it I would take it back to em asap...http://www.differentials.com/technic...ntial-problems

Re: driveshaft modification when lowering? 5.3 and 4l65e
 

If that pic is with the truck sitting on the ground, top , it looks a bit too long,
I think I have one inch of travel on the yoke (in/out) at the trans

Re: driveshaft modification when lowering? 5.3 and 4l65e
 

Forgot this one !

Re: driveshaft modification when lowering? 5.3 and 4l65e
 

See if the ds is rubbing on the cross member where it goes through. The trailing arm mount cross member.

Re: driveshaft modification when lowering? 5.3 and 4l65e
 

That yoke looks bottomed out. I lowered a F100 years ago without looking at driveshaft length. I ate up the ring and pinion in the rear in 20 miles after lowering it.

Re: driveshaft modification when lowering? 5.3 and 4l65e
 

I pulled the driveshaft out, I am having it shortened an inch today. In addition, I found that the front u-joint was nearly seized, keeper was coming out, and the driveshaft was not phased. Also, they over greased the u-joint and shot grease all over the underside of my truck. I am blown away how shops stay in business.

Re: driveshaft modification when lowering? 5.3 and 4l65e
 

When you say not phased what did you mean? Does yours have a slip joint in it? I asumed you had a one piece driveshaft.. hard to believe they let you take the truck with the u-joint like that..

Re: driveshaft modification when lowering? 5.3 and 4l65e
 

My understanding is that the yolks should all be aligned. The rear was correct, but the front was not, as seen in the picture. I am far from an expert on the topic though.

I was really surprised when I grabbed the yolk and could barely move it.

Re: driveshaft modification when lowering? 5.3 and 4l65e
 

Wow! That's incompetence at its best. That drive shaft is definitely out of phase, you'd think a driveline shop would have known better! Looks like you've got it fixed now though, so hope everything's good.

Re: driveshaft modification when lowering? 5.3 and 4l65e
 

Wow...that's pitiful...yes the yokes should be in line..but again...wow..I wouldn't be letting them touch my truck from now on..but I would give them an earful....who wins the award for that? was it that shop or someone else?

Re: driveshaft modification when lowering? 5.3 and 4l65e
 

Here's a good video demonstration of what your driveline was going thru.https://m.youtube.com/watch?v=Idk3BVDVHq4

Re: driveshaft modification when lowering? 5.3 and 4l65e
 

Im guessing it was the Einstein he bought the truck from, the same guy who was smart enough to leave out the gear lube......

Re: driveshaft modification when lowering? 5.3 and 4l65e
 

I'm actually unsure of who phased it wrong initially, but I know the shop had pulled it out to replace the trans and rear end, so I would have hoped that they caught not only the phasing, but the seized ujoint as part of the diagnostics. I am definitely unimpressed with their abilities. I should be getting the Driveshaft back today from the shop doing the shortening and will report back if it cured the whining/grinding with being shortened, phased, and replacing ujoints.

Re: driveshaft modification when lowering? 5.3 and 4l65e
 

Well, I got the driveshaft shortened, re-phased, balanced, and replaced all of the u-joints. I slapped it all together to find out the noise that was being heard is definitely coming from the rear end. To say I am frustrated with the shop's inability to diagnose and repair is an understatement. The noise is quite pronounced when slightly turning the wheel to the right and loading the passenger side of the truck at slow speed. No noise when going straight or turning left.

Re: driveshaft modification when lowering? 5.3 and 4l65e
 

Have you checked the wheel bearings?
You said the noise was louder when turning correct?

Re: driveshaft modification when lowering? 5.3 and 4l65e
 

In actually replaced the front wheel bearing on the passenger side because that was my first thought too. After replacing that, I had someone else drive it so I could listen for the issue, and it's definitely in the rear. Because of that, I am taking it back to the shop that replaced the ring and pinion last week.

Re: driveshaft modification when lowering? 5.3 and 4l65e
 

Did you check the REAR wheel Bearings ??

Re: driveshaft modification when lowering? 5.3 and 4l65e
 

where are you located in san diego ? im in Poway and there are very few shops here I will use. but do know of a few.

Re: driveshaft modification when lowering? 5.3 and 4l65e
 

I did the standard wiggle test, no play in the rear wheel to speak of. I didn't want to tear into it, since it should be covered under the repair the shop did. I just wish I had more confidence in the shop itself.