New transmission ideas

[jhiggy94]

I may have just blown the transmission on my project truck. It was the original th350. My question is that what should i do now? Would it be best to look for another th350 or try to rebuild the one that i still have, or would it be better to swap in a newer automatic or manual transmission? If this is the case what is the best transmission to use that will withstand a lot of hard work.
Thanks
Jake

[Longhorn 70]

It depends on what you are trying to do. If you are going to restore to factory, TH350. If you are going to drive it a lot, have a mild engine and aren't pulling loads, and are concerned with mileage, a 200 4R may be a good thing. It will work the engine less at highway speeds.

The 200 R4 can be set up fully hydraulic and has overdrive. It is like a 700R4 in a TH350 package.

[jhiggy94]

Im not really concerned with setting it up to factory. But i should mention that this is a k20 and i plan on using it to haul some heavy loads and go off road some and basically be used like a truck.

[mrein3]

Originally Posted by jhiggy94

I may have just blown the transmission on my project truck. It was the original th350. My question is that what should i do now? Would it be best to look for another th350 or try to rebuild the one that i still have, or would it be better to swap in a newer automatic or manual transmission? If this is the case what is the best transmission to use that will withstand a lot of hard work.
Thanks
Jake

Originally Posted by jhiggy94

Im not really concerned with setting it up to factory. But i should mention that this is a k20 and i plan on using it to haul some heavy loads and go off road some and basically be used like a truck.

Years ago I converted my K10 from a 3-speed manual to a th350. I ran through all the numbers. The cost of a th350 rebuilt compared to a 700r4 and just couldn't justify the extra money to put in a 700r4 over a th350. The gas - even at today's prices - still doesn't justify it.

However, now that I've got about 10 years on the th350 I still kick myself for not going with a 700r4. You WILL go a lot further on a tank full of gas but that isn't my biggest kick-myself-in-the-butt issue. It is the engine spinning at 3200 rpms on the freeway in 70mph zones. That is a lot of r's which translates to lots of noise in an already noisy cab.

Some day, if this economy ever gets better and I have money to spend again, I'm going to take my perfectly fine th350 out and replace it with a 700r4.

Soooooo
Long story short, I would take that th350 out, pick up an Advanced Adapters 700r4 replacing a th350 output shaft, have a reputable shop build a 700r4 with said output shaft, move the engine forward the 1-7/8" the 700r4 "K case" is longer than the th350 "K case", put in the 700r4, and be done with it.

If you need to pull a load, the 700r4 in 3rd gear (not overdrive) is the same as a th350 in 3rd gear (a th350s "Drive" gear). Leave it in third, benefit from the lock-up converter locking up in 3rd gear while pulling, and don't worry about it. If a load is going to kill a 700r4 in 3rd, it is going to kill a th350 in 3rd and is probably too much for a K20 to be pulling around anyways.

[MSHax]

I've never had any problems with any of the 700R4 I've installed. I've done some major abusing to a few and they've held up. I've made the change from th350-th400 on trucks that I used for pulling/hauling, but had things like bands go out. I like the newer transmissions, except for the fact that my hummer has ripped through (3) 4L65e, sure it's supercharged, but still, the 4l65e shouldn't blow out that easily.

If you're not going computer controlled, my vote is on the 700R4 so you get the cool overdrive feature, just buy the lock-up kit.

I'm currently getting ready for my 4L60e swap, but being too cheap to get it. :P

[Longhorn 70]

If it is a K it might be a problem to put a 200-4R in...I think all the tail housings are integral....700R4 then...You'll love the first gear off road.

BTW MSHax, I love my 700R4 and had a beefed up Olds BB in front of it from 1998 until this year. A well built 700 will take a beating.

The 200-4Rs will to...The Buick GN crowd love them.

[jhiggy94]

What do you guys think about this website?
http://www.transmissioncenter.net/pe...automotive.htm

[WIDESIDE72]

My vote is for a 2004r if your truck is 2wd. I have had trucks with 200 4r and 700r4 and prefer the 2004r since the first gear is nit as low giving less rpm drop from 1st to second.
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[WorkinLonghorn]

Just out of curiosity jhiggy94, what exactly seems wrong with your current transmission?

[jhiggy94]

I was driving going about 40 when all of a sudden i had almost no power to go anywhere at all. It would still idle along at about like 5 mph but there is a little hill by my house and i hit the gas to go up the hill and there was nothing there. i ended up having to get towed up that hill. When i shifted the transmission from D to 2 to 1 i could sometimes feel it shifting. I dont know enough about transmissions to be able to tell what is wrong with it.. Does this give you any idea?

[Fitz]

Originally Posted by jhiggy94

I was driving going about 40 when all of a sudden i had almost no power to go anywhere at all. It would still idle along at about like 5 mph but there is a little hill by my house and i hit the gas to go up the hill and there was nothing there. i ended up having to get towed up that hill. When i shifted the transmission from D to 2 to 1 i could sometimes feel it shifting. I dont know enough about transmissions to be able to tell what is wrong with it.. Does this give you any idea?

That does not sound like a catastrophic failure. By that I mean the sprag housing shattered leaving large chunks of aluminum scattered around inside the case or something similar that makes LOTS of bad noises. The internal parts for the TH350 aren't that expensive. Upgraded bands, a rebuild kit for the pump and new clutches should be about 100.00. Armed with the Chassis Overhaul Manual, the Chassis Service Manual and the Factory Assembly Manual there hasn't been a job yet that I was not willing to tackle on my truck. I always looked at it as a learning experience and, since your trans is already down there isn't much you can actually break if you use the manual. You will be surprised at how detailed the overhaul manual is. it's NOT like a Chiltons.

The manuals are still available so pick one up, take a look at how involved a rebuild actually is then make up your mind to attempt it yourself, take it to a local shop or just replace it.