How long would it take?

[PhoenixZorn]

How long would it take to remove a bad TH400 tranny and put in a good one?? No lift, just working fromt he ground with jack stands, what have you... The blazer I'm picking up this week only goes in reverse, and I can get a working 400 for about $100...

What is the spline count of TH350, TH400, 700R4 and SM465?? If any of the others have the same spline count as the 400, would they be an easier swap?

 

[metto]

if you can unbolt the tranny tunnel and build some kind of lift that is inside the cab, it will speed the process a whole lot. i would estimate about 4-5 hours if someone is helping you. if you are alone, it will take a lot longer. spline counts are
-th350- 27spl
-th400- 32 spl
-sm465- 10spl
-th700r4- also 27 spl, but has a 1in longer output shaft IIRC.
hope that helps
oh yea, a 4l80e i think is also 32 spl, but agian i think the output shaft is longer

 

[sled_dog]

later SM465s are 32 spline, same as th TH400. However that would definetally be a more difficult swap. I can lift a dry automatic transmission myself. I can't lift a SM465. Not to mention the whole conversion process of new pedals, hydraulics, clutch stuff, blah blah blah. Another 400 will be your easy bet.

Drain the fluid, 2 people should be able to lower it down after that. Should just be the shifter linkage, transfer case, crossmember, bellhousing bolts, vacuum line, and torque converter bolts in your way. Really not a difficult job. Removing and installing transmissions can be pretty easy IMO. Puting it in will be harder. I recommend a jack and the pan fromt he bad trans. Put the bad pan on the good trans(and remove the filter from the good trans) then use to jack to jack the trans up in place. 2 people really helps for guiding it without slipping off the jack. Onces it up, reinstall the filter and good pan. I won't claim it will be a fast process, definetally not if its your first time, but overall it shouldn't be really hard. Heck to remove the old one you should only need a 9/16 wrench Well 7/16s if you include the driveshaft.... and maybe 5/8.

Unbolting the transmission tunnel is assuming that there is one to unbolt. I know the last K5 I owned didn't have a bolt in tunnel. The tunnel was spot welded and seam sealed in place. No bolts.

 

[3 on the tree]

Last one I did was a 78 K5, took all day.Tried to use a regulaar floor jack, but the T-case made it roll off. Finally got some of my stepdaughter's football playing boys to bench press it in for me.

 

[PhoenixZorn]

Lol... that's great.

I won't be doing this myself hopefully... I asked because the guy I'm getting the truck from has all the help to get it done, I just wanted to make sure it wasn't an all day job for 3-4 guys... I'm hoping that if I bring the working tranny down with me (and a case of beer) they'll help me do the swap right there... then I can go rent a trailer to tow the tub and parts back myself rather than them making the trip up to Waterloo, WI from Rockford, IL... It's a bitch of a drive both ways for sure. I know these guys are capable of doing the swap right in their shop, but if it was going to be an all day thing, I would just trailer the truck and let them trailer the tub and parts...

Oh, the new tub is already cut and ready for a 465 tranny, as it had one on it's old frame... my truck will be the working body for the new tub, and the second truck will be my daily driver until Big Red is redone... and yeah, I'm pretty sure I'll be sticking with the same color scheme... the only difference will be that it won't have the kewl Furd hoodscoop. =)

Scenario: You buy a truck with a poor engine and great tranny, and you replace the engine with a 295hp 380ft/lb 356 SBC... the truck blazes, and all you have left is the frame, engine, tranny, and drivetrain... you get another truck with a 400 small block and a TH400 tranny that only goes in reverse and a rust free tub to boot....

Do you:

A. Rebuild the blazed truck leaving the working parts on it with the new tub, using the immensely more powerful 356 SBC and SM465... get air conditioning out of the deal, a completely rust free body and a strong motor...

-or-

B. Do a body swap on the rusty truck with the new tub, using the motor and tranny from the burned truck... same gain... but I don't know which one would be "easier." I know that no answer is going to be "easy"... but I am not a mechanic, nor a mechanic's son, but I will work on my own truck until the mechanic comes...

 

[Cricket]

Good to see you on the rebound, have fun with your new build.

 

[PhoenixZorn]

ttt.... no one answered my scenario question... =(

 

[Cricket]

IMO rebuild the burned truck, probably not as hard as you think. No rust and now germ free.

This is a good opportunity for you to learn, pick up a shop manual or Haynes/Chilton and go to town putting your baby back together.

 

[PhoenixZorn]

Started a new post on the walkthrough.... I was just told that the TH350 with NP208 T-Case is shorter in total length than a TH400 with NP208 T-Case... I need to know what the deal is... If I don't have the right stuff, it would be pointless to go try to do the swap...

Mudhound, if you happen to read this post, happen to have a TH400 laying around at your place?