Anyone...700 OD trans swap ??? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

too many · 09-24-2003, 12:13 AM

Has anyone swapped a 700 tranny into a 4x4 with a 205 t.case? I am thinking of replacing the 350TH with a 700odrive in my 72 half ton. I want to keep the 205. I think advance adapters makes an adapter for this? I also want to change from 3.08 gears to a 3.73.

My question is.. What kind of problems will i encounter? I think driveshaft lenghts will need to be changed? What to do about column shift selector? Any thing else?

Thanks , Steve

barraza · 09-24-2003, 08:37 PM

I haven't done it but I have been planning on it for a while. There are two ways to do it.

First way is to get the new output for the 700 from advance adapters. It has the same spline count and length as the 350 trans so it will plug right into the transfer case adapter you now have. Cost is about $175-$200 plus the trans must be completely torn down for install.

Second way is to use an adapter bolted in place between the 700 and your 205 adapter. It takes care of the extra length the 700 shaft sticks out. Not sure of the cost. BTW, most sources say that there will not be enough spline engagement if you just cut the stock 700 shaft off to the right length.

You will have to shorten / lengthen the driveshafts as required or you could move the engine forward the correct amount. I think it would be easier to move the engine forward but you would have to check clearance between the crossmember/oilpan and the front axle. Shouldn't be a problem if you have any lift. IIRC the length difference is 1.625" if you use the AA shaft. The spacer route requires another couple inches.

K5KRAZIE · 09-25-2003, 01:33 AM

I did it, awhile ago. Used an Advanced adapter shaft for the 700. Also kept the lock up feature of the trans.

ckhd · 09-26-2003, 06:12 PM

Oh, wow. Do I have to relive it? Did it on my '72 'burb.

Let's see... I bought the tranny from Bowtie Overdrives, and they put their output shaft in when they built it. That's all the adapting you need. The bolt pattern is the same, but you will have to use metric bolts to hook the tranny to the t-case.

You have the option of either shortening the rear driveshaft and lengthening the front, or move the engine forward 1 3/4". I opted to move the engine. If you decided to move the engine, make sure you get the bolt hole positions right, or you'll be like me with an extra set in the frame!

I got a shift linkage kit from Bowtie Overdrives too that made hooking all that back up pretty easy.

I got a "TV Made Easy" kit from them too. You have to have the right kind of carb (the right shape linkage). I guess the "easy" part is installation. It is almost infinately adjustable, so it's taken a while to get my shift points where I want them.

Make sure your engine is stout. The engine I had (notice I said "had") in my 'burb was one of those generic targetmaster engines. It was way too gutless to move that heavy 'burb in OD. I put in an engine with more torque, and it was better, but I want to get ahold of a BB, because I actually think I'll get better mileage with it (not having to downshift all the time).

I didn't have to mess with the tranny crossmember at all. I did get a torque converter lockup kit from Bowtie Overdrives too. It lets me manually lock the converter in 2nd & 3rd.

One word of caution, here's how my mileage went:

Before, w/ the targetmaster & TH350: 11mpg
After, w/ the targetmaster & 700r4: 7mpg
After, w/ the targetmaster & 700r4 and a carb overhaul: 11mpg
After, w/ the different engine & 700r4: 11mpg

I was told that an increase of 40% was to be expected. I think that my main problem is that I'm running a 6000 lb Suburban. I spend a LOT of time in 3rd because my engine isn't beefy enough to keep it in OD all the time (and I live in a mountainous area).

I've been tempted to put it in my '69 K10 swb when I (eventually) get it all done. I think in something that light, it would stay in 4th a lot more and actually get a lot better mileage.

72beast · 09-27-2003, 11:43 AM

funny you should ask.
I'm working on a deal right now for that very same set up...
it's a 700r4/205 combo...so I will need this info too...

Mikeflyer · 09-27-2003, 11:50 PM

Just finished installing the 700r4 with a 205 txfr case in a 72 K-10 shortbed. I too used a bowtie overdrives trans and the install went very smoothly although I did have two issues with the trans but Bowtie worked with me every step of the way to resolve the problems. I elected to move the engine forward approx 1 3/4 inches as this seemed to be the easiest and cleanest way to complete the install. This prevented having to shorten/lengthen drive shafts, build or bend transfer case shift linkage. It did require moving the engine crossmember forward but after all was completed this was a relatively painless way to go. The only concern that you might have is with the rearend gear ratio. I run 4:11s with a 33 inch tire and am turning about 1800 rpm at 65 mph on the freeway. I have a crate 383 with lots of torque which works out very nice. The 2nd/3rd lockup feature in probably the feature that I use the most, it works great when towing my boat.
If you have any addtional questions please feel free to pm me or email me if you want.
Good luck.

72beast · 09-28-2003, 12:04 PM

Mike,
I will be asking you more ? about it...I was going to put in a doubler but was thinking that a 700 would get me a lower first gear and the forth gear for freeway driving...

Mikeflyer · 09-28-2003, 11:33 PM

Looking forward to hearing from you. Will help with any info that I can.

Mikeflyer

too many · 09-28-2003, 11:35 PM

Thanks for all the help!! Will probably be a winter job... Just want to start lining things up now.
Any particular year tranny best? Car -vs- truck?????

Mikeflyer · 09-29-2003, 11:50 AM

Can't help you out with good year vs bad year on the trans. I bought a transmission from Bowtie Overdrives. It was a level 2 trans that has been modified to handle the horsepower and type of driving that I do. The following is their web site.

www.700r4.com

Mikeflyer

**diggy** · 10-02-2003, 02:05 AM

hey mike fllyer...did bowtie put in a t350 shaft when you bought it or did you do it after. i assume you put a 205 behind it.

Mikeflyer · 10-02-2003, 01:32 PM

Diggy
Bowtie put in the adapter shaft to go from the 700r4 to the NP205 transfer case. They had the shaft in stock and installed it when they built the transmission.
Mikeflyer

72beast · 10-02-2003, 03:40 PM

diggy,
I've been doing my homework on this too...
http://advanceadapters.com/
has a replacement end shaft for the 700r4 to the 205...then you use a th350/205 adapter plate...

**diggy** · 10-02-2003, 04:18 PM

does anyone know or have they asked, if you put a doubler to a 700r4 is there any issues with using a T400 32 spline shaft with the 700r4? will bowtie deliver it that way?

72beast · 10-05-2003, 12:28 PM

diggy...
I just built a doubler adapter plate that I was going to run on my TH350/NP205 but like you can see I bought a 700r4/NP205 set up. I have the NP203 apart and ready to bolt up to the double, but the trans I just bought has the TH350 Advanced adapter end nose on it, so I'm now sure whats going to work for me...when I get my 350/205 out of the truck and have the 700/205 sitting next to each-other I will see what I have. I do have a hook up on the shaft that goes between the 203 and 205 so I'm thinking he could just make the shaft fit a 205 with the TH350 input (think its 27 spline)...If not then I'll sell the doubler plate...

09-24-2003, 12:13 AM	#1
too many Registered User Join Date: Jul 2001 Location: nw IL Posts: 211	Anyone...700 OD trans swap ??? Has anyone swapped a 700 tranny into a 4x4 with a 205 t.case? I am thinking of replacing the 350TH with a 700odrive in my 72 half ton. I want to keep the 205. I think advance adapters makes an adapter for this? I also want to change from 3.08 gears to a 3.73. My question is.. What kind of problems will i encounter? I think driveshaft lenghts will need to be changed? What to do about column shift selector? Any thing else? Thanks , Steve __________________ "My wife says I cant have them all - I tell her I can try!"

09-25-2003, 01:33 AM	#3
K5KRAZIE Registered User Join Date: Oct 2002 Location: Wa. State Posts: 352	I did it, awhile ago. Used an Advanced adapter shaft for the 700. Also kept the lock up feature of the trans. __________________ TRUCKS '72 K5 '06 mega dually

09-26-2003, 06:12 PM	#4
ckhd Registered User Join Date: Oct 2000 Location: St. Johns, Arizona Posts: 2,660	Oh, wow. Do I have to relive it? Did it on my '72 'burb. Let's see... I bought the tranny from Bowtie Overdrives, and they put their output shaft in when they built it. That's all the adapting you need. The bolt pattern is the same, but you will have to use metric bolts to hook the tranny to the t-case. You have the option of either shortening the rear driveshaft and lengthening the front, or move the engine forward 1 3/4". I opted to move the engine. If you decided to move the engine, make sure you get the bolt hole positions right, or you'll be like me with an extra set in the frame! I got a shift linkage kit from Bowtie Overdrives too that made hooking all that back up pretty easy. I got a "TV Made Easy" kit from them too. You have to have the right kind of carb (the right shape linkage). I guess the "easy" part is installation. It is almost infinately adjustable, so it's taken a while to get my shift points where I want them. Make sure your engine is stout. The engine I had (notice I said "had") in my 'burb was one of those generic targetmaster engines. It was way too gutless to move that heavy 'burb in OD. I put in an engine with more torque, and it was better, but I want to get ahold of a BB, because I actually think I'll get better mileage with it (not having to downshift all the time). I didn't have to mess with the tranny crossmember at all. I did get a torque converter lockup kit from Bowtie Overdrives too. It lets me manually lock the converter in 2nd & 3rd. One word of caution, here's how my mileage went: Before, w/ the targetmaster & TH350: 11mpg After, w/ the targetmaster & 700r4: 7mpg After, w/ the targetmaster & 700r4 and a carb overhaul: 11mpg After, w/ the different engine & 700r4: 11mpg I was told that an increase of 40% was to be expected. I think that my main problem is that I'm running a 6000 lb Suburban. I spend a LOT of time in 3rd because my engine isn't beefy enough to keep it in OD all the time (and I live in a mountainous area). I've been tempted to put it in my '69 K10 swb when I (eventually) get it all done. I think in something that light, it would stay in 4th a lot more and actually get a lot better mileage. __________________ my 2¢ - t.i.o.l.i. Bowen 1968 K20 fleet 1969 K10 swb fleet 1972 K10 Suburban 1972 C10 lwb step 1992 K1500 'burb 1995 K2500 'burb 1997 C1500 'burb 1999 K1500 2000 K1500 'burb Why do I own so many Suburbans?

09-27-2003, 11:43 AM	#5
72beast TONYP Join Date: Oct 2001 Location: So Cal Posts: 100	funny you should ask. I'm working on a deal right now for that very same set up... it's a 700r4/205 combo...so I will need this info too... __________________ 72 K/5 350/205 SOFT-TOP DOUG THORLEY HEADERS A/C CUSTOM REAR BUMPER http://www.socalbigdawgs.com/tr/7.18.03/DSC04290.JPG

09-28-2003, 12:04 PM	#7
72beast TONYP Join Date: Oct 2001 Location: So Cal Posts: 100	Mike, I will be asking you more ? about it...I was going to put in a doubler but was thinking that a 700 would get me a lower first gear and the forth gear for freeway driving... __________________ 72 K/5 350/205 SOFT-TOP DOUG THORLEY HEADERS A/C CUSTOM REAR BUMPER http://www.socalbigdawgs.com/tr/7.18.03/DSC04290.JPG

09-24-2003, 08:37 PM	#2
barraza Registered User Join Date: Jul 2003 Location: N. Alabama Posts: 131	I haven't done it but I have been planning on it for a while. There are two ways to do it. First way is to get the new output for the 700 from advance adapters. It has the same spline count and length as the 350 trans so it will plug right into the transfer case adapter you now have. Cost is about $175-$200 plus the trans must be completely torn down for install. Second way is to use an adapter bolted in place between the 700 and your 205 adapter. It takes care of the extra length the 700 shaft sticks out. Not sure of the cost. BTW, most sources say that there will not be enough spline engagement if you just cut the stock 700 shaft off to the right length. You will have to shorten / lengthen the driveshafts as required or you could move the engine forward the correct amount. I think it would be easier to move the engine forward but you would have to check clearance between the crossmember/oilpan and the front axle. Shouldn't be a problem if you have any lift. IIRC the length difference is 1.625" if you use the AA shaft. The spacer route requires another couple inches.

09-27-2003, 11:50 PM	#6
Mikeflyer Registered User Join Date: Sep 2002 Location: Paso Robles, CA Posts: 11	Just finished installing the 700r4 with a 205 txfr case in a 72 K-10 shortbed. I too used a bowtie overdrives trans and the install went very smoothly although I did have two issues with the trans but Bowtie worked with me every step of the way to resolve the problems. I elected to move the engine forward approx 1 3/4 inches as this seemed to be the easiest and cleanest way to complete the install. This prevented having to shorten/lengthen drive shafts, build or bend transfer case shift linkage. It did require moving the engine crossmember forward but after all was completed this was a relatively painless way to go. The only concern that you might have is with the rearend gear ratio. I run 4:11s with a 33 inch tire and am turning about 1800 rpm at 65 mph on the freeway. I have a crate 383 with lots of torque which works out very nice. The 2nd/3rd lockup feature in probably the feature that I use the most, it works great when towing my boat. If you have any addtional questions please feel free to pm me or email me if you want. Good luck.

09-28-2003, 11:33 PM	#8
Mikeflyer Registered User Join Date: Sep 2002 Location: Paso Robles, CA Posts: 11	Looking forward to hearing from you. Will help with any info that I can. Mikeflyer

09-28-2003, 11:35 PM	#9
too many Registered User Join Date: Jul 2001 Location: nw IL Posts: 211	Thanks for all the help!! Will probably be a winter job... Just want to start lining things up now. Any particular year tranny best? Car -vs- truck????? __________________ "My wife says I cant have them all - I tell her I can try!"

09-29-2003, 11:50 AM	#10
Mikeflyer Registered User Join Date: Sep 2002 Location: Paso Robles, CA Posts: 11	Can't help you out with good year vs bad year on the trans. I bought a transmission from Bowtie Overdrives. It was a level 2 trans that has been modified to handle the horsepower and type of driving that I do. The following is their web site. www.700r4.com Mikeflyer

10-02-2003, 02:05 AM	#11
diggy Registered User Join Date: Aug 2003 Location: Las Vegas Posts: 137	hey mike fllyer...did bowtie put in a t350 shaft when you bought it or did you do it after. i assume you put a 205 behind it.

10-02-2003, 01:32 PM	#12
Mikeflyer Registered User Join Date: Sep 2002 Location: Paso Robles, CA Posts: 11	Diggy Bowtie put in the adapter shaft to go from the 700r4 to the NP205 transfer case. They had the shaft in stock and installed it when they built the transmission. Mikeflyer

10-02-2003, 03:40 PM	#13
72beast TONYP Join Date: Oct 2001 Location: So Cal Posts: 100	diggy, I've been doing my homework on this too... http://advanceadapters.com/ has a replacement end shaft for the 700r4 to the 205...then you use a th350/205 adapter plate... __________________ 72 K/5 350/205 SOFT-TOP DOUG THORLEY HEADERS A/C CUSTOM REAR BUMPER http://www.socalbigdawgs.com/tr/7.18.03/DSC04290.JPG

10-02-2003, 04:18 PM	#14
diggy Registered User Join Date: Aug 2003 Location: Las Vegas Posts: 137	does anyone know or have they asked, if you put a doubler to a 700r4 is there any issues with using a T400 32 spline shaft with the 700r4? will bowtie deliver it that way?

10-05-2003, 12:28 PM	#15
72beast TONYP Join Date: Oct 2001 Location: So Cal Posts: 100	diggy... I just built a doubler adapter plate that I was going to run on my TH350/NP205 but like you can see I bought a 700r4/NP205 set up. I have the NP203 apart and ready to bolt up to the double, but the trans I just bought has the TH350 Advanced adapter end nose on it, so I'm now sure whats going to work for me...when I get my 350/205 out of the truck and have the 700/205 sitting next to each-other I will see what I have. I do have a hook up on the shaft that goes between the 203 and 205 so I'm thinking he could just make the shaft fit a 205 with the TH350 input (think its 27 spline)...If not then I'll sell the doubler plate... __________________ 72 K/5 350/205 SOFT-TOP DOUG THORLEY HEADERS A/C CUSTOM REAR BUMPER http://www.socalbigdawgs.com/tr/7.18.03/DSC04290.JPG



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