Drive shaft grew?

[Scott91370]

Having an issue on my 85 getting my drive shaft back in, it's like it grew an inch and a half.

I pulled the entire rear half of the truck apart - if it was bolted in, it came out. Painted everything and installed a flip kit when I put it back together. Everything went together and fit properly.

Pulled the entire front end apart next to clean and paint - again if it was bolted in, it came out. Entire engine, engine cradle/front suspension. I also did 2.5" spindles and 2"springs, put the engine in and now the drive shaft doesn't fit.

I know lowering will bring the rear axle close to the transmission but thousands of these have been installed and I haven't seen anybody talk about getting the driveshaft shortened or getting a new one.

With the drive shaft pushed as far into the transmission as possible the caps on the u-joint are still at least an inch too far back to go into the pinion yoke.

Is it possible to install the engine too far back? I don't remember any slotted holes for motor mounts.

Thanks in advance for any information you guys & gals might have!!

 

[Grumpy]

Hi Scott,
By the looks of it, you haven't had a reply yet and also perhaps have already figured it out. When you lowered the rear suspension you effectively moved the rear diff closer to the transmission. Think a right-angle triangle where the long side was the original length the driveshaft needed to span the distance from the transmission to the rear yoke. Now move to the shorter of the long spans and notice the difference in length.

Simply stated, you may need to shorten your driveshaft.

 

[Scott91370]

Hi Scott,
By the looks of it, you haven't had a reply yet and also perhaps have already figured it out. When you lowered the rear suspension you effectively moved the rear diff closer to the transmission. Think a right-angle triangle where the long side was the original length the driveshaft needed to span the distance from the transmission to the rear yoke. Now move to the shorter of the long spans and notice the difference in length.

Simply stated, you may need to shorten your driveshaft.

Totally get the lowing it makes the distance between the transmission and pinion shorter but the weird thing about it was I removed the drive shaft after it was lowered and had plenty of space to do so. Then after I finished the other work it wouldn't go back in. So I'm not sure if the engine may have moved back just a bit on the mounts or what - the holes aren't really slotted but they are slightly bigger than the bots but I wouldn't think enough to move it that far. In the end I did measure and shorten the drive shaft about 3/4" and it went back in like it should.

Thanks for the response!

 

[Bennyt]

The flip kit brackets should have offset holes to move the axle back.

If you do need to do something about the driveshaft...

Shortening, straightening, balancing, new u-joints should run you about $125 based on what I paid recently in PHX.

Also, if you have a 700r4, a shaft out of a '90's Caprice should be the correct length as that is what I used.

I used Fort Worth Gear and Axle for some driveline stuff in the past and was satisfied.

 

[Brett77]

where in Phoenix did you get yours done i need mine done Thanks

 

[Brett77]

Bennyt where in Phoenix did you get yours done i need mine done Thanks

 

[Scott91370]

The flip kit brackets should have offset holes to move the axle back.

If you do need to do something about the driveshaft...

Shortening, straightening, balancing, new u-joints should run you about $125 based on what I paid recently in PHX.

Also, if you have a 700r4, a shaft out of a '90's Caprice should be the correct length as that is what I used.

I used Fort Worth Gear and Axle for some driveline stuff in the past and was satisfied.

The flip kit did have holes to move everything back but it was still not correct. I decided to give up and have Ft. Worth Gear & Axle. Had it back next day and it fit perfect.

 

[Bennyt]

The flip kit did have holes to move everything back but it was still not correct. I decided to give up and have Ft. Worth Gear & Axle. Had it back next day and it fit perfect.

Glad it worked out. I missed the part in your post earlier today where you already had it done. My eyes are tired I guess.

 

[Bennyt]

Bennyt where in Phoenix did you get yours done i need mine done Thanks

TAD Driveshafts in North Phoenix off the 17.
I paid $105 cash for straighten, balance, U-joints, etc. He can do all the work and then mark the shaft so you can powdercoat and bring it back for assembly.

I would have liked to have used the higher quality Spicer joints that don't have the grease fitting as they are stronger but since I was starting with a Caprice shaft, I really didn't have that option.

I plan to use them for an aluminum shaft I need for my Nova as well. Very nice guy and easy to deal with.

 

[Brett77]

Thanks Bennyt i will give them a try after my flipped rear end i need it shortened.

 

[rpcraft]

Maybe it was a really cold day when you took that driveshaft out

 

[shiftpro]

I wouldn't mind an extra 1.5 on my driveshaft.

 

[WFO]

I wouldn't mind an extra 1.5 on my driveshaft.

That's what she said.

 

[73c20jim]

Quit stroking it.