Benefits and difficultly of swapping trans

[carney93]

So the TH350 in my '84 is burnt, and instead of putting another 350 in it I was thinking about a 700R4. I measured the 700 in my suburban and the 350 in the truck, overall length was only a 1/8 inch difference between the two. What all whould I have to change and is the extra gear worth it?

[Ziegelsteinfaust]

Depending on which rear gear you have it can be very much worth it.

If you have 2.73's I would re-gear to 3.55's to enjoy full benefit.

[69chevytrucker]

should bolt right up but you would have to figure something for the shifter extra gear so shifting wont line up you could put a floor shifter in

[carney93]

As far as the gear ratio goes, I have no idea. The SPID sheet is gone and I haven't crawled under the back of the truck to see if there's a tag on the rear end.

[Rich84]

Holes in the frame are there to move the cross member..Well worth it. I was able to use my driveshaft also. Got a junkyard column with the extra gear.

[crashz]

Lower first gear on the 700 as well. Makes the trucks much more drivable.
A well built 700 from a reputable shop will be just as strong as the 350, if not better.

Now is the time to add: a trans temp guage, a deep pan and the biggest cooler you can find. You'll also need a way to lock the torque converter (dash switch or so).

[Gmc-76]

So the TH350 in my '84 is burnt, and instead of putting another 350 in it I was thinking about a 700R4. I measured the 700 in my suburban and the 350 in the truck, overall length was only a 1/8 inch difference between the two. What all whould I have to change and is the extra gear worth it? If you do end up doing this swap, can you post a thread on how to do it and the difficulties/problems faced in the process if you have any?

[maple square]

I just went the other way(700r4 to the TH350). You will need to move the crossmember back, the trans dipsticks are different, if you still have the original bracket for the kickdown cable you will need one for the 700R4, need a T.V. cable, trans cooler lines will work just have to bend a little bit to fit. I'm still using the 4 speed column, but you wont have that luxury. You will also need wiring to lock the converter up.

[carney93]

There's one thing I'm having trouble understanding, I've searched and got mixed answers and ended up more confused instead of understanding. When exactly does the torque converter lock up? Does it lock up in 3rd and overdrive, just overdrive, after you hit a certain MPH? If someone could help me, I'd really like to understand when the lock up engages.

[jd21476]

I took mine to a local shop to swap it out from the TH350 to the 700R4. It was $3300 with a 3 year warranty. I heard the hardest part is getting it to shift right with the TV cable.

[Gryndar]

http://www.bowtieoverdrives.com

I used.

http://www.bowtieoverdrives.com/cata...php?ITEMID=107

http://www.bowtieoverdrives.com/cata...php?ITEMID=330

http://www.bowtieoverdrives.com/cata...php?ITEMID=221

Was easy with the above items to do the swap. They have great customer support also.