In stalled a 9" rearend in my 55 chevy. The different rearend move the pinion yoke back 3/4" so now my drive shaft end to end pay is 1 1/2" to bottom out in transmission. Being the transmission yoke spline shaft is 3 3/4" this has the yoke half in the transmission. A pretty big hotrod parts online vender where I bought the rearend ***embly says this is ok, that's how they figure them. Everything I researched I found 3/4- 1". Thoughts??
If it's a concern you can buy yokes in different lengths. I went through this recently on my '39 Chev with a driveshaft I felt was a bit shorter than I felt good about. I found a 7" yoke and simply cut it off to the length I wanted, and ground a new beveled edge on the end. Way cheaper than having a new driveshaft built.
Everything I know about driveshafts is gleaned from Denny's Driveshaft. I've always followed their guidelines and have never had any problems. They have been very helpful with any of my questions. https://www.dennysdriveshaft.com/
Slip yoke in the trans is .5-.75" according to the driveline shop I use. There is longer rear end yokes out there also.
Been on there site. Everything I searched in the past always came up 3/4 to 1". I may try the 1 1/2" and see just a cruiser car
Thanks , I would be looking at 3/4" longer to be at that figure but I know that the measurements I found in the past
At 1 1/2" onto the trans spline, I think that you are on the fence, but OK under normal driving IF the yoke fits snug on the splines. If either the splines or yoke have worn and a bit sloppy, I would get a different yoke that is longer.
tail shaft bush or the extension housing bushing you'll find out when it is eaten up and the speedometer starts dancing
Why not measure went the yoke is bottomed out and when the yoke just pulls all the way out? Then you will KNOW what kind of length you're talking about. I would shoot for just a little less than 1/2 way in (with weight on the wheels........ 6sally6 Me tink the MOST damage would occur IF the shaft bottoms out! (wait...........we still talking about DRIVEshafts,right?!!)
Did bottom it out and check, that's where I'm at ,half way., also the place I got the 9" rear end ***embly said it should be 1/2 ways, just though I always read where it should be 3/4 to 1 "but half way now on mine there's 1 1/2". Probably going to try it and see, just a cruiser, no tire burning, Were still talking shafts do know which kind. lol
I’d like to get some opinions on whether an 1/8th of an inch would cause wear on anything? I don’t know, that’s why I’m asking
Guess that's a no brainer. I was trying to find out what the + and - limits should be on the yoke. I always though 3/4" to 1" was standard until the online hotrod parts place I bought the new rear end ***embly from said half way in, lots of difference.
Circle track parts.... ever see how much a rear end moves . They have the up to 8-9”... saved my bacon many times... I buy them the longest I can and cut them with a cut off saw if needed. Never lost one a track either. Chamfer them on my bench grinder before putting them on the drive shaft... hot rodding at its finest.
From personal experience on the way to the Street rod nationals in Tulsa in 1973 too short of yoke that is sticking out too far will eat the bushing and tear things up pretty bad. The one that burned up on me right outside of Marietta OK welded it's self to the tailshaft.
Maybe we should talk about starting with a “factory yoke”. Then look at what GM, Ford, etc do and place them. Then look at what happens if you use a longer one to not have to work on the drive shaft I’m sure you know now, too much “hanging out” can cause an issue, but what is safe? How much can hang? After putting blocks to raise the rear on my ‘57, I’ve found I need to replace the seal in the TH 400 when it sits for a long period of time. It’s a factory yoke, I had. New drive shaft made for it long before I needed to put the blocks in. Could there be too much rear bias on it? If it ever warms up enough I’ll see how things sit. In a street/hotrod vehicle, how much drive shaft movement is there? I quoted your reply because it seems relevant to the discussion
How I have used a long yoke on a too short drive shaft is to put just the yoke in to see how far it will go. This ***ures the face of the yoke is making as much surface contact with the bushing as possible and protects the seal. Some transmissions will let it go in all the way. I compare what's needed by looking at the original yoke. If 3 to 4" were inside the trans I set the new yoke to that and see if the u-joint will work, if not and the driveshaft is still to short you must lengthen it. If the trans has no stop and there is at least 4" or more inside the seal I use the longer yoke. It's not a cure all. If you YouTube "Dirt modified driveshaft/transmission in car" there is posted film of a front u-joint and long yoke of the driveshaft moving in and out of the trans a how far back the joint is at times Think of 25 cars on a 1/2 mile track all doing what you are watching. Definatly changes your opinion of what you cau use on the street.
And please put a restraining strap in. If your driveshaft should be unfortunate and exit the transmission, well let's just say it can get nasty. Speed shops sell a kit that bolts in near the front of the driveshaft, only requiring holes to be drilled.
Did closer measurements this morning. end to end to bottom out is 1 3/8". The shaft is 4" spline. with 2 1/4 " yoke in transmission plus transmission spline sticks out 3/8" so there is 2 5/8" of spline connection.
Total length from seal to the end of the bushing is approx. 1 1/2 inches .By your measurements the yolk should be 3/4 of an inch past the bushing.How much it will move in or out during suspension travel only you can figure out.I would get a longer yolk as others have said and be on the safe side rather than take a chance losing a bushing which will cause a leak,a vibration and a possible u joint failure.New yolks aren’t expensive.
In my opinion the "halfway" theory is useless. The yoke should be no more than 1" back from bottomed out.
I agree.We have always used the 1 in back when measuring for a new shaft.Also never heard of the halfway thing.To me it sounds like the OP doesn’t want to buy a new driveshaft or yolk and wants someone to tell him it will be okay
No , have no problem buying new drive shaft, infract I have one that just came but when I gave measurements when I ordered , the new one was the same length as my old one, which they said half in was correct. That's why I posted , being I always read 3/4" to 1". The last 2-3 post addressed this, so new one going back for 1/2" longer one that will give me 7/8" to bottom out. Picture of there order chart
No offence taking, Thought it was always around 3/4 to 1 , just checking after tech I bought through said 1/2 way.
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