View Full Version : TH400 slip yoke in a 4L80E?


KYCamaroman
05-16-2011, 12:19:26 PM
I am swapping from my TH400 to a 4L80E in my 70 Camaro. I removed the yoke from the 4L80E and installed the TH400 yoke into the back of the 4L80E and it fits great to include the seal marks lining up exactly. My question is does anyone know if it would be advisable to use the TH400 slip yoke for the conversion? I did notice the 4L80E yoke uses a larger universal joint. Can the 4L80E yoke be used as a slip yoke (same length as the TH400 yoke) by removing the bolt which holds it on the output shaft. Any and all advice would be greatly appreciated.

Thanks, Andy

Louich
05-16-2011, 07:07:07 PM
unless you have the output shaft machined down in the 4l80 they usually won't slide in enough, they are same spline as turbo 400, i should have machined mine down when i was building it but ended up machining out some of the yoke inside to slip over it.

KYCamaroman
05-17-2011, 08:48:58 PM
Given the fact that the 4L80E slip yoke uses a larger (which would seem stronger) u-joint I want to use that yoke. I guess I should have asked the following question; Can the 4L80E slip yoke be used without the bolt holding it in? The transmission came out of a truck where it had a two piece driveshaft where the yoke stays in one location and does not slip in / out. Will the fact that the bolt being removed somehow cause transmission fluid leakage?

jakeshoe
05-17-2011, 09:45:13 PM
No and yes.

JAMMINJ007
05-17-2011, 09:49:38 PM
Given the fact that the 4L80E slip yoke uses a larger (which would seem stronger) u-joint I want to use that yoke. I guess I should have asked the following question; Can the 4L80E slip yoke be used without the bolt holding it in? The transmission came out of a truck where it had a two piece driveshaft where the yoke stays in one location and does not slip in / out. Will the fact that the bolt being removed somehow cause transmission fluid leakage?
Mine did. I later bought a different slip yoke for 1350 u-joints.

KYCamaroman
05-18-2011, 01:34:41 PM
What would the solution be Jake? would it be possible just to weld a cap in place of where the bolt and washer were to cap off the center of the yoke? Really need to know my options. Do you know what parts I need to use? The driveshaft which I will be using is a stock shaft out of a 97 Chevy 2500 pickup. Hopefully you will know what size the u-joints are for that vehicle. I am running a 10 bolt rear end so I am sure that I will need a different yoke for that too by going this route.

KYCamaroman
05-18-2011, 01:35:50 PM
JamminJ007, Where did you get said yoke?

ZS10
05-18-2011, 03:36:27 PM
http://www.summitracing.com/parts/IED-SY-400-1310

I used this one.

jakeshoe
05-18-2011, 06:43:03 PM
97 one tone would use a 1350 joint.

The bolt on yoke is just that, it's a bolt on, not meant to be a slip.

I recommend buying the correct part instead of cobbling together something that will cause problems.

JAMMINJ007
05-19-2011, 01:07:11 AM
JamminJ007, Where did you get said yoke?
Here ya go:happy: http://cgi.ebay.com/ebaymotors/NEW-DRIVESHAFT-SLIP-YOKE-32-SPLINE-1350-JERICO-4L80E-_W0QQcmdZViewItemQQhashZitem43a2ddc7bbQQitemZ290495252411QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

JAMMINJ007
05-19-2011, 01:08:42 AM
What would the solution be Jake? would it be possible just to weld a cap in place of where the bolt and washer were to cap off the center of the yoke? Really need to know my options. Do you know what parts I need to use? The driveshaft which I will be using is a stock shaft out of a 97 Chevy 2500 pickup. Hopefully you will know what size the u-joints are for that vehicle. I am running a 10 bolt rear end so I am sure that I will need a different yoke for that too by going this route.
I welded mine and it still leaked:screwup: so I just bought the right part meant for the job:cool:

KYCamaroman
05-19-2011, 12:27:11 PM
How about a 1350 yoke for a GM 10 bolt rear end?

KYCamaroman
05-19-2011, 12:51:03 PM
Jake, The truck that the transmission came out of was a 3/4 ton GMC. Is it also a 1350 u-joint unit?

JAMMINJ007
05-19-2011, 02:50:00 PM
How about a 1350 yoke for a GM 10 bolt rear end?
You can get a hybrid u-joint one with 1310 and 1350 ends on it.

KYCamaroman
05-19-2011, 03:32:02 PM
I think my 10 bolt is a 7.5 because of the tiny points which poke out of the bottom of the housing unlike the 8.5 units. Does that seem correct for a 70 Camaro?? Seems off to me.

Andy

JAMMINJ007
05-19-2011, 04:20:46 PM
I think my 10 bolt is a 7.5 because of the tiny points which poke out of the bottom of the housing unlike the 8.5 units. Does that seem correct for a 70 Camaro?? Seems off to me.

Andy
me too, from what i understand all 2nd gen came with at least a 8.5

jakeshoe
05-19-2011, 08:56:04 PM
Ya,
Sorry posted thinking it was a 1 ton. 3/4 ton will be 1350 as well.
Measure to be sure. Cap diameter and overall width.
I think a 1350 is 1.125" cap diameter with 3.622" width.

1970 models used the 8.2 rear. I would upgrade to something better. Pretty weak and not worth investing any money into.

Just use a conversion joint there until you get a bigger rear.

KYCamaroman
05-21-2011, 12:27:19 AM
That's correct Jake. The shaft which came along with the 4L80E has 1350 u-joints. The large section of the shaft is long enough, longer than the original shaft, for me to use to make my new driveshaft.

Yes, my 70 Camaro has the 8.2. It has the correct casting numbers and dates for a 70 Camaro, probably the original for the car.

Considering this transmission and now the entire rear suspension .... replacement was unexpected and came in the middle of an engine build money is of importance. Since I have to make a shorter driveshaft anyway and buy a new slip yoke for the 4L80E transmission would like to go with larger u-joints. Who sells a conversion u-joint to go from a 1350 to a u-joint which comes in a 70 Camaro? Wouldn't this be a weak link? I would rather grenade a rear diff than throw the tail end of a driveshaft.

What rear end would you switch to keeping in mind $$ ?

KYCamaroman
05-21-2011, 08:18:44 PM
What is the best way to tell the difference between a 8.2 and a 8.5 externally? Can you tell?

jakeshoe
05-21-2011, 08:20:33 PM
I can tell by the cover and housing shape but it's hard to explain.

hhott71
05-21-2011, 08:57:42 PM
70's had 8.2 10 bolts except the SS and Z28 cars got the 12 bolt.
1971-1981 was a 8.5" 10 bolt.