MONTE CARLO 700r4 swap 87 Monte

[Hamrtym2]

Good morning everyone! My 1987 Monte has been in the family since 92. We bought it with 56k miles on it. It still had the fully original drivetrain until I bought it from my dad. It had a 4.3 v6 fuel injected with a th200C 3 speed transmission. (MV9 code) I swapped the engine to a v8 carbureted 350 with a fuel pressure regulator etc. Ecm is still in the car for everything else but it doesn’t control the engine. Now I’m swapping to a 700r4 transmission and I’m also doing rear end but that isn’t the topic today. To swap to this 700r4 what do I need to know? Will I have to change the gear select cable and kickdown cable? I assume I can get a new transmission crossmember and I know I’ll need a new driveshaft. However the biggest concern and question is the 700r4 lock up. How would a guy wire up this lock up? I’ve heard guys say do it with a toggle switch but I really don’t want to have to deal with flipping a switch all the time. Did the 200C 3 speed have a lock up? If so then I’m assuming I could find that wire and use it. Either way, whether it did or didn’t, can someone run me through what I need to know for the lock up and the cables? It’s a column shift car. How would I identify if the 200c has a lock up? FYI yes it has a 200c 3 speed. Verified by the RPO sticker for proof. Had typical “fb mechanics” trying to argue with me that the 200C wasn’t factory and that my car must not be a real 87 even though the RPO shows a 200C 3 speed from factory with a 1987 vin number. 🙄

 

[stew86MCSS396]

You’re close yes. I just posted the RPO sheet on a reply of an earlier comment. So this car was a 4.3 fuel injected car. It’s now a 350 carb with vortec heads and a 600cfm Holley carb. It didn’t come with the 200r 4 speed. It came with the th200C 3 speed. Currently still has that 3 speed to this day. Now this 3 speed still works. However she’s tired. Especially after now being behind a 350 power plant. The tail shaft on it has TONS of play. So much so that it vibrates through the floor and the steering column at highway speeds. Grab the shaft and she’s loose inside that trans like a prom queen on prom night. That coupled with the fact it’s a 3 speed is why I’m changing. I’ve got a 700r4 I bought from a wrecked 2wd early 90s Chevy that a local older man owned. Truck it came from had 75k miles on it. So simply put, I chose 700r4 because I’ve had a firebird before with a 700r4 behind a mild built 305 and i was impressed believe it or not. Also because it currently doesn’t have a 200r 4 speed. It’s actually a 3 speed. RPO confirmed built with the 3 speed. To my understanding the 200c 3 speed already has lock up? Correct? I’m handy and decent at what I do but I’m no master mechanic here so if you’ve got a little more explanation for me of what to do for this then by all means dumb it down a hair for me. I do have my Haynes manual as well. So it should hopefully have wiring diagrams for the 200c in it

I hate this myriad of choices when converting stuff, why can't it be a simple plug and play!!! Chances are the truck 700r4 will have a electronic VSS. Your 200c came with a cable driven VSS. It's po$$ible to $wap the early 4-bolt tailhou$ing 700r4$ to cable drive one provided you can get the drive/driven gear. Other alternative is to convert your da$h to an electric $peedometer. There's also a electronic cable drive device that Abbott makes.

Edit: I think certain tailshaft housings used either drive/driven cable or magnetic vss so it may just be a matter of procuring the right pieces.

 

[ssn696]

An F-body 700-R4 can donate the mechanical speedo tailhousing even if the rest of the trans is toast. I'm not positive, but I think you can swap the reluctor ring for a plastic speedo gear and retainer clip. The internet or Forum will provide clarity.

Don't despair - you are on the right path if you are not looking for 400 hp.

 

[pagrunt]

An F-body 700-R4 can donate the mechanical speedo tailhousing even if the of the trans is toast. I'm not positive, but I think you can swap the reluctor ring for a plastic speedo gear and retainer clip. The internet or Forum will provide clarity.

Don't despair - you are on the right path if you are not looking for 400 hp.

Should also get the mechanical speedo tailhousing from a B or D body 700-R4. These also have a transmission mount pad that'll be closer to older Turbo Hyromatics.

 

[stew86MCSS396]

Should also get the mechanical speedo tailhousing from a B or D body 700-R4. These also have a transmission mount pad that'll be closer to older Turbo Hyromatics.

Nice totally forgot about that I've only heard of the B-body 700r4 tailhousing with the extra trans mount and never seen one in person. Funny thing is if you do a search, seems like there's alot of listings for that particular piece. I wanted to do something similar considering I have a 4L60E sitting here in my driveway but the show stopper was I have the later removable bellhousing and the 5 bolt tail. Anyhoo turns out if you get the B-body tail, you should be able to get away using a stock 200-4R crossmember or good excuse to buy a Gforce. DS would still need to be shortened. Left to right...TH400, TH200-4R, TH350 and TH7004R. Your existing TH200C is going to be most similar to the TH350 mounting location. Notice the red line showing how similar the mount is for 3 of them.

 

[CopperNick]

+100 on ssn696's suggestion to change out the seals as a "while I'm there" task to do. I had forgotten that your engine could have that one piece rear seal housing that can be removed and the seal swapped without messing with the main cap. As for the pump front cover seal, it can be extracted by various ways, including using a couple of self drilling sheet metal screws to create lugs that you can grab with a side puller and gently pop the seal free. Others swear by seal pulling tools, other get 'er done using screw drivers. Whatever the method, again be careful and gentle; mess up that seal pocket and there is no fix for it except a new cover. As for putting the new seal in, I will leave the ways and means of it to others. I know what I would do/use and actually have that tool in my inventory although it was created and meant for another purpose.

Oh, yeah, when I needed to replace the TVS cable on my own 700, I did manage to score one from Napa. This was just before Covid and s*** has happened but they might just still have that P/N in stock.

Nick