Hi

Very interesting discussion about this problems.
I installed a T56 Viper 6 speed tranny and the 30 teeth slip yoke is very loose going into the tranny. Can actually feel very slight play even when fully inserted. I just hope, this doesn't produce any vibrations.
The yoke to right hand tunnel clearance is also small. I even moved the tranny a touch further to the left to clear the tunnel on the right now having about 2 mm ( .080 " ) gap.
Unfortunately, as the T56 is even longer as the TKO, all moves even further back into the narrow tunnel. Drive shaft lenght is about 24 " only.
An other bad point is that there is no quick release slip yoke available in 30 teeth design.

It seems starnge that this installation problems of the tranny kits appeare so late , years after the first one was installed.

Günther

 

Motor head,

I just spent yesterday pulling FAUXRS new motor out of his 78. He had oil pressure problems on his new 355. Anyway when we pulled the TKO500 off the bellhousing we found the the input spline had burred against the rear of the SCAT crank. Not bad mind you but it did burr the splines. Unknown if issue is with tolerances due to SCAT crank and or someone took a cut on the bellhousing but we are going to solve the issue. Suggest checking tolerances between your input to crank using plastiguage. Eric's taking the TKO over to get the input shaft splines cut back .005. Yes he's using a stock bellhousing.

David

 

Thanks, I think my problem is they just send me the wrong driveshaft as I mentioned my invoice has a part number and it is DSV-C3VL1310 and it states it is for 80-82 Corvettes, so the invoice is correct but they might have put the wrong driveshaft in the box. I assume there is a different part number for 68-79 Vettes. Anyone with an older Vette have their invoice handy to compare numbers.

Hopefullly this is the problem and I can get the right driveshaft sent to me
ASAP so I can get out and enjoy the nice weather

 

I have the same 1980 keisler kit, tko600 from the group purchase, with the strap type yoke. I am just starting the install and the keisler supplied driveshaft is 26 1/2" cl to cl. The strap type yoke will only go on about 1 1/2" before it stops. I tapped it with a rubber mallet and was able to coax another 1/2" and that is it. Seems to get tighter the farther it goes on, like it is tapered.
Not too happy considering it took 11 weeks to arrive and now i will have to contact Keisler Monday further delaying the install.
Only hope is that the yoke is the only problem and i don't also end up with a too long driveshaft.

Note: I did remove the rubber shipping seal on the end prior to test fitting the yoke.

 

Well after a little reassurance from Jeff, I went out and filed a little on the tunnel wall and slightly ground the slots on the crossmember bracket to transmission mount. I now have what I would call a two credit card thickness clearance. However, on the other side I am a hair away from touching. I will try to figure out some way of pulling that cable back slightly. Any ideas?





Bullshark

 

So I think there is about 1 1/2 inches difference in length between the 68-79 and 80-82. Now here is the problem, if they cut all the driveshafts the same length then the 68-79's will have 1 to 1 1/2 inches of the shaft of the yoke showing and the 80-82's the shaft will not show at all and the yoke will be pushed right up against the rubber dust boot. In perfect world this would be OK but you get 1/2 inch out of tolerance one way or the other and you run into problems.

I might be able to get the driveshaft to fit but that would mean forcing the yoke into the tailshaft further than what it was designed for and deforming the rubber dust boot and when the yoke spins it will chew it up. I hope they have 2 different lengths as I cannot see how it would cost more to cut them one length or the other.

I could be way off base here so I hope no one gets upset about all the questions about this, hopefully I will find the answer tommorrow

 

Wayne, Here is a pic of the installation on my 70 BB. Maybe it will help with your question session tomorrow.



Bullshark

 

Some more thoughts:
1) The picture of Bullsharks driveshaft is showing about the perfect amount of yoke - this is how it should be. The margin that is acceptable is having the yoke pushed about 3/8" further into the output shaft or pulled about 1/2" further out. If you much out of this range either way, it is not where you want to be.

Bullshark, I took a look under my car again at the yoke clearance situation and I do not see any simple way of moving the cable to create more clearance. My strap style yoke was clearing the cable by at about 3/8" - I am comfortable with this amount of space. On the other side, I had about 3/16" between the yoke and the passenger side of the tunnel. I think this will be fine but I will keep an eye on it.

2) I pulled out 3 different TKO's and test fit 10 different strap style yokes onto the each of the 3 TKO's. All of the yokes fit onto all of the TKO's - it is a bit tighter fit than a solid Spicer brand slip yoke but I did not need to use a mallet to get the strap style yokes onto the output shaft - of course I had the transmission where it was easily accessible. Originally, Inland Driveline starting making these 1330 strap style yokes at our request - specifically for the Corvette/TKO crowd. I made sure to ask them to confirm that their broach (the tool that makes the splines inside the yoke) would produce a yoke that would properly fit the TKO.

3) Cutting a driveshaft a bit longer or a bit shorter will not effect the cost at all.

4) If there is a 1 1/2" difference between the 68-79's and the 80-82's, then there should be two different, distinct driveshafts. 1 1/2" is too great of a variance - this is not a one-size-fits all situation.

5) As you are all seeing, when installing a TKO into a Corvette, or any other car for that matter (Camaro, Chevelle, etc.) there is always the possibility that some minor mods may need to be made. As much as we all like to see an easy bolt-in, no mod swap, that takes 4 hours to do, sometimes this is just not possible for whatever reason. Some guys are too close to the passenger side of the tunnel, so they have chosen to cut a small section out of the tunnel for clearance, others are too close to the e-brake cable so something needs to be done there, sometimes a bellhousing doesn't line up quite as precisely as it should, etc. My advice to anyone going into this swap is to be prepared to have to adjust, trim, or "massage" something to make it fit. If you end up having to do nothing other than just bolt it in then you will be pleasantly surprised. As long as you go into the swap knowing this, you will not be upset or surprised when/if something comes up. In th eend, any mod that may be required should be minor and worth the end result of having a great transmission.
Just know the possibilities before you jump in and things will be fine.
With that said, if you are 100% adverse to any potential mods (even minor ones) then this swap may not be the best thing for you.

I hope this helps.

 

I agree 100% about "massaging" parts to make them fit, I usually expect to do this and have done so on just about everything installed in my Vette, occasionally you get something that just does not fit. In this case if there is a 1 1/2 in. difference this driveshaft ain't gonna fit as you can see the yoke on mine is back touching the dust boot. I would have to force it back so it touches the tailshaft itself in order to fit the ujoint.



My only worry is that Vette-4-Life with an 80 in a post above also got a driveshaft the same length as mine.

 

motorhead-
Your driveshaft appears too long (obvioulsy). From your picture it appears to be about 1" too long. I am interested to hear from Vette-4-life to see if his fits or if it is too long. If it is also too long than there is clearly a difference between the 68-79's and the 80-82's.

Vette-4-Life
Let us know if driveshaft fits or if it is too long. Although you may have a yoke issue (as Engraver did) which may preclude you from testing the driveshaft length.

The good news is that these are correctable issues.

keep us posted.

 

I talked to Keisler over the phone today and there is two different driveshafts and mine should be about 25 3/4 " not 26 1/2 " like I have now so they are sending me the shorter one tommorrow. I must say the customer service there ( Richard ) is top notch

 

Sounds like i should caller Keisler and get the shorter driveshaft else i will have the same issue as Motorhead.
As far as the yoke goes i used a rubber mallet to coerce it all the way in and the same to get it off again. I did this about 10 times and it now goes on/off with light tapping of the mallet, it will not go all the way on with just a push of the hand. It seems to turn freely and i noticed no scoring on the yoke shaft.
I will be starting this weekend and expect it to take several weeks since i will see lots of gunk that needs a wire wheel and POR15.

 

Sorry i came in so late on this issue. We are putting a T500 into an 82 - as part of a complete auto to manual conversion. we ran into the same problem -The first drive shaft Keissler sent had the wrong Ujoints in it. So we sent it back

Thesecond one they sent was to long - some of you are currently addressing this same issue, so we sent that one back

Now I'm waiting for the correct driveshaft to arrive! I'm hoping 3rd times a charm!

keissler has been pretty good about helping - but this seems to me that they should have figured this out long ago!

Carl Johansson

 

Bullshark, thats the same clearance I had on mine ,everything went well untill I got on it hard then it would hit the passenger side,raised car back up and moved trans over a bit,now its closer to the cable,so far no problems...

 

I do believe I will be removing the cable if I have any problems, everytime I fix my parking brake it works for a month or so then that it

 

Thats what I was afraid would happen. My problem is that there just isn't enough space between the tunnel side and the cable. I think I have the thing in a little of a bind cause when I tightend up the motor mounts the space on the tunnel side shrunk back to about a credit card thickness and the cable clearance is about the same. I tied off the cable with a large tie wrap to gain some additional space for now. ( like Motorhead, E-brakes don't work anyway ) I plan to get out the file and do a little more tailoring on the tunnel . With any luck I will be on the road to Columbia Mo. for a corvette weekend gathering this Sat.
Bullshark

 

I ran into the same driveshaft length problem on my 69 when I swapped in a 74' Super T-10 for the 69' Muncie M-21. The shaft lengths were different by I believe 3/4 of an inch or so. RedVetRacr basically explained the whole thing to me. I guess the ST-10 case is a different length than the Muncie by a bit even though they look identical. The 69 driveshaft was too long. Maybe Keisler didn't know the manual trans lengths changed in the Muncie to Richmond changeover years (I believe 73-74)...and maybe their test fit car was a Muncie car. Just a thought.

 

They know, they have 2 different lengths from what I understand, 68-76 is 26 1/2 in. and 77 - 82 is 25 3/4 in. something like that anyway, just got sent the wrong one I think, mistakes happen, as long as you try and fix the problem for the customer no big deal. Interesting though I would have thought it was a slight difference frame dimensions not the trannys

 

Slight thread hijack here...I was glad to see this thread as I am currently installing a Tremec into my '68 (fortunately, I bought the setup including custom driveshaft from a forum member who already had it installed in another '68, so I'm less likely to have wrong parts ). I test fitted the transmission last night so I can get my mounting bolt holes properly located on my newly-removable crossmember. I filled the case with 2.75 quarts of synchromesh, no problem. I slip in the yoke over the tailshaft so I have something to hold onto to turn the shaft so I can align the splines up front, no problem. However, when I pulled the yoke off the tailshaft, lo and behold gear oil starts to trickle out onto my left shoulder! Is there no seal in there??? If there is, what the heck is going on with mine?

help!

 

Roy, Not to worry, the tailshaft is sealed around the yoke spline. When you removed the yoke the seal in the tailshaft had nothing to seal against. When the transmission was new it had a temporary rubber seal plug that you heard us refer to earlier in this thread. It must be removed prior to inserting the yoke. I'm guessing you didn't remove the yoke out of your old Muncie or the same thing would have happend.

Bullshark