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front CV driveshaft/crossmember clearance

folkenheath

folkenheath

Volcano Manifolds
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I did some searching and found some people having clearance with the front CV driveshaft and the straight tranny/t-case crossmember. Well, I am finishing up my suspension build and I have a new 1350 CV and at full droop it's about 3/16" from the tranny crossmember. It doesnt move much since it's so close to the case, it's probably 5/16" away at full stuff. I built radius arms with limit straps so it shouldn't travel any further up/down. However I am wondering about the engine torqueing over and rubbing the CV. I have poly motor (clamshell replacements) and poly tranny mounts. I am running out of time as I am trying to get it back together for this weekend and I still have to finish welding my engine crossmember and the axle brackets, plumb brake lines, and reassemble everything, etc. I have had the truck apart for 6 weeks and it's coming down to the wire. Trying to see if I'll be OK for the weekend or if it's something I have to change now. I modified the stock crossmember before I got the new driveshaft and it bolts in with 14 bolts and holds the radius arms too, so if possible I don't really want to pull it out and modify it the next 2 days, since I am already running low on sleep and have a lot to do yet.


So what has been the minimum clearance that people have between the front CV and crossmember and don't break the CV/driveshaft? And how much does the transfercase front output torque down under load with poly trans/motor mounts? I can torque it in the driveway once I have it together, but was looking for real world results. I have a 550 hp big block and I plan on playing in the sand all weekend if I can get this back together in time. Looking forward to it after weeks of working on it on all the time.

Thanks in advance guys.
 
folkenheath said:
I did some searching and found some people having clearance with the front CV driveshaft and the straight tranny/t-case crossmember. Well, I am finishing up my suspension build and I have a new 1350 CV and at full droop it's about 3/16" from the tranny crossmember. It doesnt move much since it's so close to the case, it's probably 5/16" away at full stuff. I built radius arms with limit straps so it shouldn't travel any further up/down. However I am wondering about the engine torqueing over and rubbing the CV. I have poly motor (clamshell replacements) and poly tranny mounts. I am running out of time as I am trying to get it back together for this weekend and I still have to finish welding my engine crossmember and the axle brackets, plumb brake lines, and reassemble everything, etc. I have had the truck apart for 6 weeks and it's coming down to the wire. Trying to see if I'll be OK for the weekend or if it's something I have to change now. I modified the stock crossmember before I got the new driveshaft and it bolts in with 14 bolts and holds the radius arms too, so if possible I don't really want to pull it out and modify it the next 2 days, since I am already running low on sleep and have a lot to do yet.


So what has been the minimum clearance that people have between the front CV and crossmember and don't break the CV/driveshaft? And how much does the transfercase front output torque down under load with poly trans/motor mounts? I can torque it in the driveway once I have it together, but was looking for real world results. I have a 550 hp big block and I plan on playing in the sand all weekend if I can get this back together in time. Looking forward to it after weeks of working on it on all the time.

Thanks in advance guys.
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I have no clue what the clearance is but I find it funny that I am also having a c/v shaft issue. I thought it was just a u in the CV but turns out the ball/cup are shot. I had a spare but its rusted shut. Gonna hit the junk yard up tomorrow and see if I can snag one, either that or have the driveshaft shop put a new cv on. The shaft is good cv no good. As it sits right now It rattles around and hits the crossmember. I haven't had it bind yet.

As far as your situations goes, If you are concerned why not just though a couple of washers under the crossmember to drop the tcase or under the mounts to raise it.
 
this might sound dumb but still sharing my experience.

I had clearance issues as well and took the crossmember down and noticed it was bolted back in the other way around...the oposite side has a propper clearance cut but i still chopped a bit off for greater clearance.
 
Thanks for the info, I do have the clearance part of the crossmember under the CV, so I'm good there.

Also, I have the poly replacement "C" style mounts for the t-case adaptor, which wrap around the stock center crossmember. So if I put washers in there it will space the polyurethane away from the crossmember and it might be able to move around more than now. Because the poly sandwiches the crossmember.

And I hear you on the CV shaft issues. I broke my 3R CV 3 times already in the past few years. Everytime it was that ball and cup would pop out and the CV would flop around like a wet noodle. First time they fixed it on warranty. Broke it again, I thought it was compressing too much so I got a 10" slip spline on there, and also triple checked too make sure angle wasn't too much (in the end I think it was with spring wrap). They were good and only charged me for the upgrades. Broke it again.

That's when this whole thing started. I rotated the pumpkin, but I wasn't going to do that to a D44, so I found a D60. Then what about the leaf spring pad. I can machine that, but then the studs are angled. Well, why do I need leaf springs anymore anyway, I can do coils, but then I have to mount seperate shocks, FOAs are pretty reasonable, and so I don't brake it again, now I have a HAD 1350 CV in there....it never ends. But if hits the crossmember and brakes again I am going to be pretty dissapointed after all these weeks of work. I just don't know if I have time to modify it anymore. I never heard it rubbing before, but I did break it 3 times, with the big balance washer on there before I think it was the same outer radius, but who knows.

I got more done last night, I keep getting 4 hours of sleep and it's catching up with me.
 
folkenheath said:
Thanks for the info, I do have the clearance part of the crossmember under the CV, so I'm good there.

Also, I have the poly replacement "C" style mounts for the t-case adaptor, which wrap around the stock center crossmember. So if I put washers in there it will space the polyurethane away from the crossmember and it might be able to move around more than now. Because the poly sandwiches the crossmember.

And I hear you on the CV shaft issues. I broke my 3R CV 3 times already in the past few years. Everytime it was that ball and cup would pop out and the CV would flop around like a wet noodle. First time they fixed it on warranty. Broke it again, I thought it was compressing too much so I got a 10" slip spline on there, and also triple checked too make sure angle wasn't too much (in the end I think it was with spring wrap). They were good and only charged me for the upgrades. Broke it again.

That's when this whole thing started. I rotated the pumpkin, but I wasn't going to do that to a D44, so I found a D60. Then what about the leaf spring pad. I can machine that, but then the studs are angled. Well, why do I need leaf springs anymore anyway, I can do coils, but then I have to mount seperate shocks, FOAs are pretty reasonable, and so I don't brake it again, now I have a HAD 1350 CV in there....it never ends. But if hits the crossmember and brakes again I am going to be pretty dissapointed after all these weeks of work. I just don't know if I have time to modify it anymore. I never heard it rubbing before, but I did break it 3 times, with the big balance washer on there before I think it was the same outer radius, but who knows.

I got more done last night, I keep getting 4 hours of sleep and it's catching up with me.
Click to expand...

yah I hear yah, I got your email. It looks like my spare shaft the ball/cup are good. I have the U's gonna get those in tonight. I just wanted a quick solution and not an up all night/ all day on friday kind of thing. I don't want to spend any money on a new shaft/ parts because I'm building a doubler, and will be switching to fixed yoke 1410 when I swap the 60 in.
 
I added some 1/16" plates in there to gain a bit more of clearance, didnt want to mess a lot with it cause of the engine angle and drive line angles.
 
Mine used to rub on hard throttle climbs when the drivetrain would torque over. I tried adding some 1/8" washers under the foot for clearance, but no joy.

I notched my t-case crossmember right under the CV. Just cut a square hole where it would hit. Then added a chunk of 1/4" on the bottom side to brace it back up.

I'll see if i have a pic.
 
MTBLAZER89 said:
Mine used to rub on hard throttle climbs when the drivetrain would torque over. I tried adding some 1/8" washers under the foot for clearance, but no joy.
Click to expand...

How much clearance did it have while it was rubbing? Also, did it ever break because of the rubbing?
 
Probably about 3/16. This is with the flat x-member. I imagine I could have fixed the problem with poly motor/trans bushings as well.

No I never broke because of it. It rubbed on the center part of the CV so there was no edges to catch and bind.
 
Thank you, exactly the info I was looking for. I have all poly mounts and a little more clearance at ride height, so I am gonig to try it and see if it rubs. Thanks.
 
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