200 to 700 tranny swap

csbuckn · #1 (**permalink**) 07-13-09, 05:56 AM

We just pulled the 700 from the 91 brougham and want to put it in the 88 brougham. Will I just need the adapter, crossmember, tranny and drive shaft or is there more to it? We are unsure about the converter bolts matching and the drive shaft bolting to the rear. Didnt they both have the same axle with different gears?

05devilledave · #2 (**permalink**) 07-13-09, 07:01 AM

If you have the adapter for the 700, the only thing you should need for the converter are small spacers between the flywheel and converter (to make up for the added thickness of an adapter plate.) Which can be made with stacked washers, or one thick washer about as thick as your adapter plate. Also longer converter bolts to accomodate the thicker width between the flywheel and converter. Secondly, your speedometer may read wrong. The speed is read by a interchangeable gear in the tailhousing of the tranny. The gear in the 700 may not be the same number of teeth as the one in the 200. Although they too... should be swappable... the speedo gear that is. It is held in by a fork shaped piece of steel with one bolt in it on the tail housing.
Measure the length of the 200 from the top of the bell housing, to the very end of the tail housing. If its fairly equal to the 700 (within 1/2 inch or less), then the drive shaft thats in the 88 should work just fine. If not, you can swap the shafts, OR swap the tail shaft and tail housing (including the speedo gear) between the two. Both shafts should bolt to either rear end, as long as they have the same width and diameter u-joints. You should be good other than linkages, cooler lines, and dipstick.

csbuckn · #3 (**permalink**) 07-13-09, 01:23 PM

so the crossmember will not need to be swapped?

05devilledave · #4 (**permalink**) 07-13-09, 06:49 PM

I dont think it will need to be swapped. I have swapped a TH350 in place of a 700R4 before, and though it barley fit, I didnt even have to change the cross member for that either. But that too, is something that can be given a definate answer with a tape measure or once you get both trannys out, set them side by side, dead even with one another, if the the tranny crossmember mounts are pretty much exactly side by side, then you dont need to swap them. The tranny mounts have to come off anyways, when you go to install them under the swapped tranny, put the original crossmember in place, if it works, use it, if not, go grab the other and swap it.

Slacker · #5 (**permalink**) 07-14-09, 10:28 AM

When my HT4100 died I swapped it with a 307 and a th200 I got for $200. The 200 was shorter than what was in the car so I used the same cross member but just moved it forward to accommodate. (Had to drill two new holes in the frame).