TH400 bolt on yoke VS slip yoke pro's or cons

[petey-pablo]

I just bought a new driveline for my truck with a bolt on yoke.is there any pro's or cons to this versus a slip yoke? My old drive line had a Slip Yoke This is going behind a TH400 & 454BB on my72.I am doing the work myself so I have never done this.

How tight do I have to tighten the senter Bolt? I over tightend it and my truck didn't want to move I have now loosened it up and drove my truck but now All the oil came out of the tranny through the senter bolt and made a big mess under my cab and mufflers so I had to get it towed home.. I used lock tite on the bolt and some silicone around the washer but I don't understand how this would stop the yoke from sliding back and forth if it cannot be tighted alo. It doesn't look like I can just buy a slipyoke and put it on neither for they are different, Or Can I?
Since I have done this I have now ruiend the new seal so I will have to replace it again with a new one. What is everyone useing any advise would be great thanks guys....

[clinebarger]

The bolt on yoke is for a later model 3/4 & 1 ton with the slip yoke behind the support bearing. my 85 suburban was set up this way. all 67-72 ive seen have the slip yoke at the trans because the 2 drive shafts are bolted together. you need a drive shaft out of a 67-72 TH400 truck. dont drive your truck this way it will ruin the thrust bearing/bushings in the trans

[petey-pablo]

Originally Posted by clinebarger

The bolt on yoke is for a later model 3/4 & 1 ton with the slip yoke behind the support bearing. my 85 suburban was set up this way. all 67-72 ive seen have the slip yoke at the trans because the 2 drive shafts are bolted together. you need a drive shaft out of a 67-72 TH400 truck. dont drive your truck this way it will ruin the thrust bearing/bushings in the trans

My turck has the tranny with the threads in it I was told I had the wrong yoke by the guy who made my new drive line so he gave me the threaded yoke set up..See the damage of my tailhousing and output shaft I spun the bushing on this thread http://67-72chevytrucks.com/vboard/s...d.php?t=368163 so I should have the right yoke now I even replaced the tailhousing but my problem is with the bolt not sure how tight to tighten it or if there is a better way to to this with out useing a bolt on yoke thanks...

[dwcsr]

If thats a seal in the hole its the wrong one. Once you replace the shaft you will be able to tighten up the yoke. You wore off the lip that it seats against. This is what the seal should look like

[clinebarger]

Do not use the bolt on yoke! The treaded output shaft only means it was originally out of a truck with bolt on yoke. Use a slip yoke ive had several 69s with TH400s when a trans went bad i got whatever i chould most of them had the threaded output shaft and i used the orginal drive shaft. heres a pic of what the yoke & driveshaft should look like (just not as rusty). i read your other post. your tailhousing is trash buy a used one and have a seal & bushing installed. find a new driveline shop and ask them how the want you to measure the shaft and have one built.

[brad_man_72]

the driveshaft needs slip in it somewhere.

[2tons of fun]

x2. if you use a bolt on yoke you must have a slip in the drive shaft.


and again, see how short the spline section is on the fixed yoke unit? your problem before was that you were bottoming the yoke out on the internals and not seating all the way.

i ran across this when i bought my new shaft and yoke and they banged me for $25 to mill 3/4" of the splines off of it so the bolt seat was fully against the end of the output shaft.

[petey-pablo]

Originally Posted by brad_man_72

the driveshaft needs slip in it somewhere.

A Slip, What is a Slip?

[71tahoe]

A driveshaft is longer than the horizontal distance from the transmission to the axle. At factory ride height when you hit a bump the driveshaft becomes more parallel with the engine/transmission. Parallel is a shorter distance than the driveshaft length. If you don't have some slip in your driveline then it will either break the trans mount, axle u-bolts, u-joints, transmission internals, ring/pinion or any combination. Either the transmission yoke has to slip on the output shaft or a section of the driveshaft has to compress/expand.

[dwcsr]

Originally Posted by petey-pablo

A Slip, What is a Slip?

If the driveshaft maker gave you a shaft that has a slip joint in it then you use a bolt on yoke. If there is no slip joint in the shaft then use a slip on yoke. You will need a different seal for a slip-on than a bolt-on yoke.

Normaly you have to machine the slip-on yoke to be used with a bolt on tail shaft but you wore off the lip that the bolt-on yoke seats against because you use a slip-on that kept hitting the lip. When I converted to slip-on for my bolt-on tail shaft I had to machine the yoke so it would not hit the lip on the tail shaft and do the damage yours has to the shaft.

[petey-pablo]

I thought I would post some picutres of what I have. Now is a SLIP the part that can move in and out at the end of the driveline? I didn't have it before the new one was made? I thought this would be easier to do sorry for all the questions but if I had the money I would just take it to the transmission shop & have this done. I am just tring to understand what I am doing wrong and what parts I need to do the job right.. I took a picture of both ends of my driveline the end with the ajustable scopeing end goes at the rear end the other is the end that goes to the tranny this is was I was told by the driveline shop..

[petey-pablo]

I also have a bolt and a special washer that goes in the center to bolt the shaft in.. Do I have the wrong seal this was the one I was useing before thenI just bought a new one so this is the old one and Now I need to buy a new one because the one I replaced was damaged the lip was ripped off from the shaft sitting on it..

[dwcsr]

You have all the parts for a bolt on yoke. The slip joint is on the shaft. That seal looks right, BUT you still have a damaged tail shaft that will not allow you to tighen up the yoke until you replace it. The bolt has a heavy flat washer that you bolt the yoke on with and rests against the shaft lip that you don't have. So until you replace the tail shaft your still out of luck.

[petey-pablo]

Originally Posted by dwcsr

You have all the parts for a bolt on yoke. The slip joint is on the shaft. That seal looks right, BUT you still have a damaged tail shaft that will not allow you to tighen up the yoke until you replace it. The bolt has a heavy flat washer that you bolt the yoke on with and rests against the shaft lip that you don't have. So until you replace the tail shaft your still out of luck.

Ok correct me if I am wrong is There two Different types of tail shaft housing's?? Do I have the wrong one? Because I did get a replacement Tail Shaft Housing, in the pictures below I have the damaged old one painted in black and the other a good used replacement.. But the seal is bad I need to replace it because I damaged it the second time around. I over tightened the bolt and my Truck wouldn't move so I had to loosen the bolt up and I finaly got the truck to move Man this is complicated.. Shouldn't there be something that keeps the bolt on Yoke from being tightened to much or too tight on the tail housinging, because the yoke slips all the way flat on tailhousing, Shouldn't there be like a tiny little space where it wouldnt touch the housing?
dwcsr Thank you for you patience and all your help .

[71tahoe]

Originally Posted by dwcsr

You have all the parts for a bolt on yoke. The slip joint is on the shaft. That seal looks right, BUT you still have a damaged tail shaft that will not allow you to tighen up the yoke until you replace it. The bolt has a heavy flat washer that you bolt the yoke on with and rests against the shaft lip that you don't have. So until you replace the tail shaft your still out of luck.

Originally Posted by petey-pablo

Ok correct me if I am wrong is There two Different types of tail shaft housing's?? Do I have the wrong one? Because I did get a replacement Tail Shaft Housing, in the pictures below I have the damaged old one painted in black and the other a good used replacement.. But the seal is bad I need to replace it because I damaged it the second time around. I over tightened the bolt and my Truck wouldn't move so I had to loosen the bolt up and I finaly got the truck to move Man this is complicated.. Shouldn't there be something that keeps the bolt on Yoke from being tightened to much or too tight on the tail housinging, because the yoke slips all the way flat on tailhousing, Shouldn't there be like a tiny little space where it wouldnt touch the housing?
dwcsr Thank you for you patience and all your help .

This is what he is talking about. The shiny ground down part of the shaft was removed at some point. There should be a lip where the bolt-on yoke would rest to space it away from the housing when you tighten the bolt.

[petey-pablo]

Originally Posted by 71tahoe

This is what he is talking about. The shiny ground down part of the shaft was removed at some point. There should be a lip where the bolt-on yoke would rest to space it away from the housing when you tighten the bolt.

OH Thats what happen there dang I thought I ruiened it by haveing my driveline alittle short..so I have to go back to useing a different yoke then? The bolt on yoke I have would do me no good correct? It would bottom out again and ruine the seal...Dam my truck is full of surprizes...PLEASE Don't tell me that the drive line I just had made is now useless to me? Do I have to have a new driveline made again without the telescoping part just a solid one "I just want to put a new set of AAA batteries in it to make it go already"

[petey-pablo]

Damm damm damm Thank you very much I guess my truck needs to see the tranny doctor....Ouch it's ganna cost me at lease another $300 if not more to get it fixed....

Just curious would this solve my problem or would my driveline still be an issue?
1310 Series 32 spline T-400 & 4L80 Transmission Slip yoke specifically designed to be used on a T-400 & 4L80 with the Threaded Hole in the Output shaft.
http://www.dennysdriveshaft.com/p69_...wth.html#photo
This design will replace the truck style bolt on yoke with a car style slip yoke and allow for proper slip travel and bushing contact for best performance. A must for any threaded output shaft on T-400 & 4L80 transmissions. We designed this yoke to solve this problem over 25 years ago.
•Barrel Diameter... = 1 7/8 inches
•U-joint cap diameter...= 1 1/16 inches
•U-joint width... = 3 7/32 inches
•Series... 1310
•Spline count... 32

[71tahoe]

Originally Posted by petey-pablo

Damm damm damm Thank you very much I guess my truck needs to see the tranny doctor....Ouch it's ganna cost me at lease another $300 if not more to get it fixed....

Just curious would this solve my problem or would my driveline still be an issue?
1310 Series 32 spline T-400 & 4L80 Transmission Slip yoke specifically designed to be used on a T-400 & 4L80 with the Threaded Hole in the Output shaft.
http://www.dennysdriveshaft.com/p69_...wth.html#photo
This design will replace the truck style bolt on yoke with a car style slip yoke and allow for proper slip travel and bushing contact for best performance. A must for any threaded output shaft on T-400 & 4L80 transmissions. We designed this yoke to solve this problem over 25 years ago.
•Barrel Diameter... = 1 7/8 inches
•U-joint cap diameter...= 1 1/16 inches
•U-joint width... = 3 7/32 inches
•Series... 1310
•Spline count... 32

Sounds like it would work. I take it that the truck slip yoke you had tore up the tailshaft housing. What's described sounds like this slip yoke would fit the bolt on yoke housing without damaging it. Hopefully some experts will confirm.

[chevy_mike]

I would definitely call Denny's and talk to them before you bought it. From what you have posted, it looks like this will solve the problem.

Sounds like the tranny is not the original one for the truck, correct?

[dwcsr]

You already have all the parts you need. Just replace the tail shaft and be done with it.

If you use Dennys slip yoke you need to replace the drive shaft again. Denny's yoke will not work with a shaft with a slip joint in it already its for a solid shaft. I've done this coversion and have a dennys setup.

Your options are
1. Replace the tailshaft and bolt up all the parts you have.
2. Get a new driveshaft from denny's with the slip yoke and hope the tail shaft doesn't break on the first burnout.

There is not good cheap way around it that shaft needs to be replaced.

[petey-pablo]

Originally Posted by dwcsr

You already have all the parts you need. Just replace the tail shaft and be done with it.

If you use Dennys slip yoke you need to replace the drive shaft again. Denny's yoke will not work with a shaft with a slip joint in it already its for a solid shaft. I've done this coversion and have a dennys setup.

Your options are
1. Replace the tailshaft and bolt up all the parts you have.
2. Get a new driveshaft from denny's with the slip yoke and hope the tail shaft doesn't break on the first burnout.

There is not good cheap way around it that shaft needs to be replaced.

Thank you for all the help I now fully understand my problem I think I will go with option #1. Take it in and have the tailshaft replaced so they can bolt up all the parts I have.This is where it shure would be nice be my own mechanic & pay myself with a nice long drive and a good burnout at the end I will start looking around for the best place to take it, I will have to have it towed and hopfully be drive it home
Thankyou guys very very much Pablo....................