Hey all,

I have sorted out most of the issues I have had with a 1981 C3 Project car that I originally bought non-running. There were many leaks including the transmission pan which was also fixed. I took it out for its very first drive last week and I noticed that the tranmission shifts can literally slam and slam hard at times. I think this transmission may very well be on its way, I checked all fluid levels and they seem normal. But, I figured I'd be better off just putting in a new clean transmission since I plan to drive this car a lot around the city. I know this topic has been beaten to death and I read other forum posts on it. Many recommendations said get the 200 4r or just the same TH350 and I've seen some well priced ones like this which I assume should be a plug and play fit:

https://www.jegs.com/i/JEGS/555/60305/10002/-1

Now what I want to do when I consider for this upgrade is I want a trans that woll work well with my currnt carburted 350 block but also not lock me nt something that's simple enough to install that I can take it to any indie ship to put it in. Anyways, let me know your thoughts. Thanks all! Hey everyone,

I've resolved most of the issues with my 1981 C3 project car, which I originally bought non-running. Among other things, I fixed several leaks, including the one from the transmission pan. After taking it out for its first drive last week, I noticed that the transmission shifts are quite harsh at times, almost slamming. I've checked the fluid levels, and they seem normal, but I'm considering replacing the transmission to ensure reliability, especially since I plan to drive this car around the city frequently.

I've read a lot of forum posts on this topic, and it seems like the 200-4R or the same TH350 are popular choices. I've found some reasonably priced options, like this one, which I believe should be a straightforward fit:

https://www.jegs.com/i/JEGS/555/60305/10002/-1

My main considerations for the upgrade are that the new transmission should work well with my current carbureted 350 block but also be compatible with a potential future upgrade to an LS engine. Additionally, I want it to be simple enough to install that any independent shop can handle it.

I'd appreciate any thoughts or recommendations you might have. Thanks, everyone!

 

If you want an LS, either bite the bullet and get a 4L60e or better, or a TKX 5-speed manual, or Tremec Magnum 6-speed. The LS controller you use, either stock or a Terminator X Max, will be able to control the transmission. In the meantime, there are stand-alone controllers.

 

Forgive me for being a little inexperienced in this topic. But would a 4L60E work with my current carburated engine? If so would it still need a controller to get it to work? I am also looking for an affordable option my car won't be winning any races soon..

 

Hopefully I've given you a few terms to search. Do a lot of research before you buy anything. You might also want to ask at https://ls1tech.com/ as well.

Yes, the 4L60e will bolt right up to an SBC, but you'll need an independent controller to make it function.

This falls under the "don't do things twice" rule. If you know you are upgrading to an LS, perhaps do the whole swap at once. You'll waste less time, and spend less money.

I think something like this will work for a 4L60e (or 4L70e, or 4L80e).
https://www.summitracing.com/parts/s...02?seid=srese2

It will all be moot, wasted money and effort, when you switch to an LS, though. But at least you won't have to buy two transmissions.

FWIW, you can find a complete, running LS-based truck engine for the price of that transmission controller.

 

Ikarah
If you are just cruising around and are going to pay someone to do this tranny work, then I'd just get your Tubro-350 fixed.

I'm assuming from your post that you will NOT be doing this work yourself??

 

Yes, I was looking to take it to someone to do it. But to @Bikespace 's point it may be easier to just do an LS + 4L 60E swap. But, my fear is if I take a LS Engine and a 4L60E to an independent shop and ask them to drop it in the car for me I assume they're just going to say no or be confused because that's custom work no?

 

Where are you located? There are shops that specialize in exactly this, including one near me in Virginia. There are some C3 specific things that need to be considered, but this type of work is done every day at your local hot rod shop, and Forum members' garages.

The LM7 (5.3L LS-based Silverado engine with an iron block) that I picked up for a song had a 4L60e attached to it prior to my arrival. Had I been the one to buy that particular Silverado, I could have gotten the complete kit. As it was, the new owner of the truck and engine wanted that transmission, and was selling the rest (including the complete, running LM7, which included an ECU that could control the 4L60e, not that it helped me and my manual transmission). But there were millions of similar trucks, vans, and cars made with similar engines, that came with a 4L60e, and still have it attached.

At the other end of the cost spectrum from a junkyard LS/4L60e combo, GM sells connect-and-cruise crate engines. There are some LS3 options available with a 4L70e. Perhaps others, too. Not cheap, though!
https://www.chevrolet.com/performanc...rtrain-systems

 

I am located near Greensboro, NC. I honestly didn't know that. Most mechanic shops I went to were even hesitant to work on the small block motor it has in it. None of them could even fix the oil pan properly. If you have any shops you can recommend, I'd definitely be willing to give them a call and ask them what they'd charge for something like this. I wonder how much the connect-and-cruise kits cost from GM (couldn't locate it on their website as of now), Ive never heard of this either but, it looks awesome!

 

I sent you a PM.

The Connect and Cruise kits are stupid expensive. $15K and up. Your best bet is to find a part number(s) and search for those. You can buy them at a GM dealership (including online dealerships), and places like Jegs and Summit.

The junkyard swap is a lot more cost effective, but carries higher risk.

 

"slams"?
shifts firm?
that doesn't mean its going out


reset the shift cable, the th350 tvs will alter how it shifts

 

Yeah, I understand. It could be a bad torque converter or it's slipping. It's at a shop now being diagnosed, Ill find out what they tell me.

 

slipping ?

sorry , can't understand whether it is ;
hard firm or slipping.

 

Reading though all of this makes me even more certain I don't want an Automatic.
To me, considering the OP says he's not winning any races anytime soon. And has thoughts of future upgrades but doesn't sound ready to pull the trigger on that yet.
My advice here would be to repair the existing transmission and keep the car on the road short term. While continuing to do homework regarding future upgrades. There are many variables here concerning upgrades and with the OP at the mercy of others doing the work. These types of mods should be discussed at length with the person or firm doing the work. And just finding the right person or firm can take some time.

 

My money is on: Somebody installed a shift kit.
They will shift firm at lower throttle position, but "bang" at wide open.
And / or, the trans modulator has been messed with.
And / or the governor speed has been messed with.

Trans pan gaskets: You get what you pay for. Some are less than $9.
Some or over $25.

Some people throw any ol' bolt on the trans pan that's handy. The bolt bottoms out in the trans body and will never torque down the pan.
Test fit the bolts for proper length w/o a pan in place.

Pan gasket sealants come in array of choices. But how many are ATF proof? We all know that ATF is actually a cleanser besides a lube.
Permatex is aware of that and has a Permatex Automatic Trans Pan RTV. And it is ATF proof.

 

What's an easy way to tell if a shift kit has been installed?

 

You will be able to hold the trans in any gear, at any speed. And that includes down-shifting.
So, use caution when down-shifting. You don't want to slam it into 1st at 60 mph.

In "D" it will shift normally and firm depending on throttle position. But 1 and 2 are manually operated.
I have the B&M kit.
All my kick-down apparatus has been removed.
There is no hesitation up-shifting. Just the chirp of the tires.

 

You can wire a 200-4R in easy. Just do a forum or Google search for "How to wire lock-up torque converter for 200-4R" and you'll see a few methods. That's probably your least costly way to go.

Or maybe a manual 5-spd makes more sense to you? That would add sportiness to the car.

https://www.jegs.com/InstallationIns.../764-60110.pdf