4.3 to 5.7 conversion driveline.

[rchavez101]

I recently did the conversion and also rebuilt my turbo 400. Now my driveline doesnt fit. The driveline cross member is in the same holes as before. For those of you that have done the conversion did you use the same driveline? How far should the yolk slip in? Should it bottom out? I though for sure it should fit. I know there is some play where the transmission bolt goes through the cross member but not much.
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[clinebarger]

The DS should work, There will be play....The slip yoke moves in & out with rear suspension movement.

[rchavez101]

Originally Posted by clinebarger

The DS should work, There will be play....The slip yoke moves in & out with rear suspension movement.

Yeah I figured there should be play with the rearend moving up and down. I thought the transmission would be in the same location when doing a 4.3 to 5.7 swap. It does not appear that way. I will have to try again. Worst case I have them shorten the DS. If they do it would only be by a few inches if that. I will have to try it again and then measure to see what the difference is.

[clinebarger]

Ive done this swap in the past. I used V8 mounts & motor stands.....Does not move the trans.

[rchavez101]

Originally Posted by clinebarger

Ive done this swap in the past. I used V8 mounts & motor stands.....Does not move the trans.

Thanks for the info. I used V8 mounts and like I said the transmission cross member is in the same holes. I will investigate here in the next few days and see what I come up with. Thanks again.

[kenbob87]

when i did my swap my trans and tcase all stayed in the same place, i had no problems with the drive line at all.

is yours too long now or too short?

[rchavez101]

It seems to long. With the yolk all the way in i cant get the rear ujoint into the pocket on the diff. From what i can tell it will be an inch or so to long. I will try again here within the next few days. Maybe there is something I am over looking.
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[kenbob87]

you said you had your trans rebuilt are you sure that you got your th400 back? because they did make a short and long th400 and it is possible that your tail shaft and housing got switched accidently. that may be whats going on

[rchavez101]

Originally Posted by kenbob87

you said you had your trans rebuilt are you sure that you got your th400 back? because they did make a short and long th400 and it is possible that your tail shaft and housing got switched accidently. that may be whats going on

I am pretty sure I got the same tailend. I would imagine that there would be a significant difference in the 2 tail shafts. When I was trying to put it in it appears to only be about 1-2 inches to long if not less then that. I will try again and if I can't seem to figure it out I will give them a call and see if there is something that might of happened that could be making the difference in length.

[kenbob87]

yeah its a pretty noticeble differance in the two tail shafts, hmmm thats a real brain buster... ill keep thinkin and see if i can come up with anything else..

[rchavez101]

I was able to get the driveline in afterall. I took both caps off of the ujoint to get it in place. There was some play as far as the yolk. I had the truck on jackstands (frame) and measured the distance on the play of the yolk. I then lifted the rearend till the truck came off of the jackstands and then measured the distance the yolk moved. There is almost no movement on the yolk when the rearend is at ride height or all the way down. It seems to be ok. Thanks for the help.