So, I don't technically own an Oldsmobile, but I found some good info on here previously, and wanted to see if anyone had any suggestions. I am currently driving a 1982 Buick Electra with the Olds 350 diesel and TH350C. The torque converter lockup started shueddering really badly, and it's starting to slip so I need to figure something out. A local rebuilder quoted me $5000 to rebuild it, which seems insane, and I can't seem to find any places that sell reman transmissions, at least not the C variant with the lockup. Are there any shops around that sell rebuilt transmissions? Or should I just convert it to a standard TH350 or possibly 700r4 or something?

 

You can always unplug the converter clutch and keep driving it. It'll cost you two tenths of mpg but it'll literally take 5 minutes and make the car driveable again.

Those early lockup converters were notorious for sticking or shuddering all across the GM lineup. Lots got unplugged with their owners never knowing. I once bought my sister a really nice 80 something cavalier for 50 bucks because of this issue. The converter would stick locked and the car would stall at lights. The owners were fed up with it and didn't want to put a trans in it. I unplugged the converter and she drove it for 4 years before the 2.2 blew the head gasket. This was the mid 90s so it was still a nice car, even though it was a cavalier...

 

Yeah, I did unplug it for the time being, but the transmission is also slipping somewhat. I'm assuming a normal non lockup turbo 350 should bolt straight in too, right?

Ideally I'd like to rebuild or replace with another th350c, cause I do plan on road tripping this car a lot and the fuel economy adds up with no overdrive. I've already taken it 14 hours round trip to NJ and 18 hours round trip to New Brunswick, got 5000 miles on it since I got it registered in March

On another note, I know the 200r4 is a direct bolt in on the C bodies, cause the gas cars used it. Has anyone ever made one of those work with the diesel?

 

Yeah a normal 350 would bolt in it's place. You should get another quote, i would think you could get it done for less than a grand if you pull it yourself. 2k would be the absolute top if you dropped it off.

 

Yeah. I just called the local aamco, apparently the owner is very good. I will say that the $4500 quote I got was including removing and reinstalling the trans, but it still seems like a lot. I have a friend with a lift, so I could definitely yank it out myself

 

I’m on a few different automotive forums, this seemed to be pretty a common problem. Nobody wants to mess with the older transmissions, and I don’t understand why? The throw out a ridiculous price to scare you off, and if your crazy enough to give the Ok, they priced it high enough to justify the inconvenience.

Unfortunately, parts for TH350/350Cs are getting hard to come by. Last time I tried to buy a stock converter for a 350, Precision Industry wouldn’t sell one without a core. They told me converter cores are too hard to find. Who would have thought a stock common 350/400 converter would be valuable? I guess that’s what happens when they are worth more as scrap than cores.

Id get a second opinion. Find a different shop.

If your the least bit mechanically inclined, a th350 is pretty easy for a novice to rebuild. Very few special tools are needed, what tools are needed are easily fabricated with stuff most gearheads have sitting in their garage.

if you have no desire to build it yourself, and can’t find a shop to take on the project, for $4500 I’d remove it, rebuild it, reinstall it, wash, wax and detail the car, take you out to dinner, and assuming nothing seriously changes in the economy, fill the gas tank!!!

 

You can buy a really nice TCI Street Fighter series TH350 BOP non-lockup for about $3k not including whatever converter you might go with for it (they also make stock-stall range units to go with it.

It's fully built for plug and play install - I just put one up in my '72 Cutlass a few months back and it rocks.

 

Yeah, if all else fails I'll probably either just buy a normal TH350, or potentially find a 200-4r (and possibly swap in a 455 out of one of the rusted in half Toronados in my buddy's yard), but I do really want to keep the TH350C in this, because it's a diesel, and my road trip car. Even if it only drops the engine speed by around 500 rpm, that adds up over a 1000 mile trip. And also, reducing the stress on what people keep telling me is one of the worst engines ever made is always good too. I absolutely love the diesel, it's been dead reliable for me, and it gets pretty good mpg even with the transmission slipping. The looks people give you when they hear it are hilarious too!

 

I wonder if there are any kits out there to put something like a 4L60E in this application? That might work too

 

The rpms only drop about 150 or so. Its not all that much.

 

How many miles on it? Has it been serviced, could be a clogged filter for the slippage. How does the fluid look?

If the transmission is rebuilt be certain the cooler and the cooling lines are flushed.

For the shudder try Lubegard Shudder Fix, it works well and is inexpensive.

5k to rebuild a TH350 is insane, it sounds like a "We don't want the job" price.

 

When I got the car it had 93k miles, and the transmission likely has never been touched. When I got it I changed the fluid, resealed the pan, and changed the filter, and it was fine for a while. I think it may have been slipping a bit the whole time, but the lockup shuddering started maybe 2000 miles ago, and got progressively worse

 

Lubegard Instant Shudder Fixx is worth trying.

 

My 81 GMC 1/2 pickup originally had a 350C. I had the TCC on a manual switch. The lockup knocks off a lot more than 150 rpm.

Now that I’m thinking about it, I have little doubt the torquey 455 I swapped in pushed the converter a lot harder than the weezing 350 diesel ever would.

 

i did use that Lucas goo, and it helped somewhat, but I think the torque converter is beyond saving.

 

The rpm calculators all say to add 200 rpm for converter slippage. With the low HP diesel I figured 150 was a safe bet.

 

Rad, Just to be clear I'm not suggesting Lucas rather Lubegard Shudder FIXX made specifically for that symptom.

 

As Matt said, the lock up converter is more rpm than 150. More like 250 rpm, talking a stock 1600 stall TH250C converter to 300 rpm for most mild performance applications. My current 2100 stall 4L80E is at least 250 rpm, a factory reman 6L converter. Go 2004R, a direct swap. I would guess the diesel throttle body's TH350C kick down is in the right spot for the TV cable, should be. Then you can do a gear swap since you will drop rpm 700ish rpm over your TH350C.

 

Oh, the TH350C has a kickdown cable? I thought it was completely vacuum controlled. Yeah if anyone can confirm that the tv cable can just go straight where the kickdown is, I'd definitely do a swap like that. I'd rather not touch the rear end though, it was freshly rebuilt maybe 10k miles ago and looks perfect inside. I also don't know how hard it is to get fifferent ratios for this rear end. I'm not sure exactly what it is, but it's BOP 10 bolt, and a very large variant

 

Yes, the TH350(C) has kick down. That rear is either a 7.5" or 8.5" GM corporate 10 bolt rear. Gears and posi are available everywhere. My 81 Delta 88 had a factory Olds 307 and TH250C and a 2.41 7.5" open rear end. The better first gear 2.74 vs your current 2.56 ​​​is also will help launch, even without a gear change.

 

If you're doing long road trips and have access to a lift, don't waste time on another 3-speed. Hunt down a BOP-pattern 200-4R. It bolts right up to that Olds block, uses the same driveshaft length, and that overdrive gear will completely transform how the car cruises on the highway.

 

I understand, and I'll try it next time I go to the parts store, but I think I really just need a new torque converter and trans rebuild before I drive this thing to Chicago

No luck on transmission shops locally yet, I gotta call them again cause they never got back to me

 

there are 2 crossmembers for your car . You will need the crossmember for a 2004R, if you decide to go that route. The frames on the gm b bodies are like the g body frames. The crossmembers will not slide. Crossmembers are not easy to find as most salvage yards cut them. Ther is a man in Taladaga that has 2 left. I bought one last week. He may have a 2004R also

 

Finally heard back from the local AAMCO, I think I'm gonna take it there. He gave me a rough estimate of 2500, which is definitely within the range I would expect. My coworker apparently worked with the owner of this AAMCO previously at a racecar shop, so I think it'll be in good hands. Now to save up the money to get it done.... Great timing for it to need a transmission at the same time I'm buying a house...

 

Out of curiosity does anyone happen to know what the stock torque converter is rated at for stall? I can't find any torque converters that say they're meant specifically for the diesel, and places like rockauto just say "low stall" without giving a spec