Trying to swap the 700r4 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

pnkflyd850 · 03-02-2007, 12:52 PM

Hey guys, well I have searched this forum for a couple of days before I posted and didn't find much. I have a 83 silverado and swapped the 700 for a 350, the only problem is the crossmember position on the frame. I have searched everywhere and all I got was "slide the crossmember up the frame to fit a 350 trans". Well I can't exactly do that because of the body mount on the left side on the frame is preventing me from doing that

. The right side is able to slide up to the matching holes, but then no luck for the left side. I've taken care of the driveshaft length and all, so I'm just left with this problem. I've talked to lots of people and they say the same thing, "just slide it" but I can't!!! Please help!!!

Any ideas will be VERY helpful!! -Thanks

Yea, 700r4 to a turbo 350 this is what I got so far...The one side(right side) is good, it's just this left side. Right now the new trans is in, but the crossmember is at a pretty bad angle, so it's just sitting there.

[IMG]

[/IMG]

piecesparts · 03-02-2007, 04:35 PM

When I put my 700 in my 84 SWB, after removing the 350C tranny, all I did was slide the crossmember back and drill a couple new holes. You will have to show a pic of what your hitting for a better evaluation. I did the same thing for my son's truck.

84 400 · 03-02-2007, 05:18 PM

So are you taking an orginal 700r4 truck and swapping to the 350C??

Larry K · 03-02-2007, 08:31 PM

New guy here. I did just what your doing R700 4 in my 83 c20 but had the parts truck yet and used the cross member out of the '85 (doner truck). I took out a TH 400, I don't recall but can say in my case the cross members were different. May be a trip to a junk jard will be needed. Also I used the small wiring harness for the lock up torque converter release switch at the brake pedel and that harness went to the trans and a vac. switch. I was lucky as I had a complete truck to pick off of. Changed rear end too. Went fromTH400 and 4:11 to OD and I think 3:46 ?? and for this truck maybe 16-17 MPG if careful. Larry K.

pnkflyd850 · 03-02-2007, 08:56 PM

Thanks, looks like I'll have to try that, I'm not having much luck with anything else. Genoa? I'm from Mchenry

Srubydo1986 · 03-02-2007, 09:40 PM

if that dosnt work u could modify the cross member and relocate the holes on the crossmember and bend it a bit to get it over the body mount brackets in the way.

Larry K · 03-03-2007, 11:36 AM

small world yes just north of DeKalb. On the same subject I put that 400 in a work truck of a friend and had used the 400 cross member I am Not sure but may have the 700 crossmember from that yet.

SulphurDave · 03-06-2007, 11:01 PM

I went from 700r4 to th350 and all i did was cut that part off in your pic that wraps around the frame on the driver's side and made it look like the passengers side, slid it up some, everything matched up except for 2 holes on the driver's side in which i drilled new holes and voila.

82c10 · 03-06-2007, 11:28 PM

Quote:

Originally Posted by 84 400

So are you taking an orginal 700r4 truck and swapping to the 350C??

i assume to a non-lockup

MylilBowTie · 03-07-2007, 12:15 AM

700r4 and th350c are both lockup transmissions. I have also cut the extra off on the stock crossmember. I made it where the crossmember went inside the frame rails and not inside / outside. Had to drill one bolt hole, I went from a th350c to a th400.

If you don't want to cut it look for a double hump crossmember out of a 3/4 or 1 ton. Only draw back would maybe the way the exhaust is ran. Just looking at the one picture it might clear and not need to be ran different.

82c10 · 03-07-2007, 03:50 PM

Quote:

Originally Posted by MylilBowTie

700r4 and th350c are both lockup transmissions. I have also cut the extra off on the stock crossmember. I made it where the crossmember went inside the frame rails and not inside / outside. Had to drill one bolt hole, I went from a th350c to a th400.

If you don't want to cut it look for a double hump crossmember out of a 3/4 or 1 ton. Only draw back would maybe the way the exhaust is ran. Just looking at the one picture it might clear and not need to be ran different.

where do you see the thread starter state it was a 350c? i didn't, i know that is a lock-up tranny, that is one of the reasons i got rid of mine, and am going to a regular th350

MylilBowTie · 03-07-2007, 04:32 PM

Just that, a th350c is a lockup torque convertor as well as a 700r4. Some may or may not know that. Trying to help sorry you took offense to it for some reason. th350c isn't any weaker than a regular th350. But a good torque convertor is going to run a good bit more money.

I went to a th400 because I couldn't find a th350 that would hold up in my 84. I tried four different ones and they didn't suit me. At any rate Ive had bad luck with them. One of the th350s I had rebuilt the rest was used. It does take more power to run. But I rather have something I don't have to worry about making it home.

pnkflyd850 · 03-07-2007, 08:46 PM

yea, it's just a regular th350..I tried searching junk yards for different trucks and I keep finding the same crossmember. So I may just cut off the end that rides up the side of the frame and make it flat just like the passenger side as 'sulphurdave' said. Thanks again everyone

03-02-2007, 12:52 PM	#1
pnkflyd850 Registered User Join Date: Feb 2007 Location: Newnan, Ga Posts: 5	Trying to swap the 700r4 Hey guys, well I have searched this forum for a couple of days before I posted and didn't find much. I have a 83 silverado and swapped the 700 for a 350, the only problem is the crossmember position on the frame. I have searched everywhere and all I got was "slide the crossmember up the frame to fit a 350 trans". Well I can't exactly do that because of the body mount on the left side on the frame is preventing me from doing that . The right side is able to slide up to the matching holes, but then no luck for the left side. I've taken care of the driveshaft length and all, so I'm just left with this problem. I've talked to lots of people and they say the same thing, "just slide it" but I can't!!! Please help!!! Any ideas will be VERY helpful!! -Thanks Yea, 700r4 to a turbo 350 this is what I got so far...The one side(right side) is good, it's just this left side. Right now the new trans is in, but the crossmember is at a pretty bad angle, so it's just sitting there. [IMG][/IMG] Last edited by pnkflyd850; 03-02-2007 at 05:45 PM.

03-02-2007, 04:35 PM	#2
piecesparts Parts and more parts Join Date: Nov 2003 Location: Lebo, Kansas (middle of nowhere Posts: 6,821	Re: Trying to swap the 700r4 When I put my 700 in my 84 SWB, after removing the 350C tranny, all I did was slide the crossmember back and drill a couple new holes. You will have to show a pic of what your hitting for a better evaluation. I did the same thing for my son's truck.

03-02-2007, 05:18 PM	#3
84 400 Sb 400 club Join Date: Nov 2005 Location: NH / MA Posts: 2,741	Re: Trying to swap the 700r4 So are you taking an orginal 700r4 truck and swapping to the 350C?? __________________ 1984 chevy c10, built 400sb,.(SOLD) 77 K10 Project / daily driver "The Grinch" http://67-72chevytrucks.com/vboard/s...d.php?t=318363 1956 Willys Wagon (327 chevy) Project (Now Buick 225) 1980 Corvette L-48 4 speed 1992 Mustang GT built 5.0 5 speed 1985 C10 LWB Sold 1982 K10 SWB plow truck Parted out 1986 D30 M1028 fire brush truck Parted out

03-02-2007, 08:31 PM	#4
Larry K Registered User Join Date: Feb 2007 Location: Genoa IL Posts: 6	Re: Trying to swap the 700r4 New guy here. I did just what your doing R700 4 in my 83 c20 but had the parts truck yet and used the cross member out of the '85 (doner truck). I took out a TH 400, I don't recall but can say in my case the cross members were different. May be a trip to a junk jard will be needed. Also I used the small wiring harness for the lock up torque converter release switch at the brake pedel and that harness went to the trans and a vac. switch. I was lucky as I had a complete truck to pick off of. Changed rear end too. Went fromTH400 and 4:11 to OD and I think 3:46 ?? and for this truck maybe 16-17 MPG if careful. Larry K.

03-02-2007, 08:56 PM	#5
pnkflyd850 Registered User Join Date: Feb 2007 Location: Newnan, Ga Posts: 5	Re: Trying to swap the 700r4 Thanks, looks like I'll have to try that, I'm not having much luck with anything else. Genoa? I'm from Mchenry

03-02-2007, 09:40 PM	#6
Srubydo1986 The Crazy Machanic Join Date: Jan 2007 Location: Nokesville Va Posts: 1,437	Re: Trying to swap the 700r4 if that dosnt work u could modify the cross member and relocate the holes on the crossmember and bend it a bit to get it over the body mount brackets in the way.

03-03-2007, 11:36 AM	#7
Larry K Registered User Join Date: Feb 2007 Location: Genoa IL Posts: 6	Re: Trying to swap the 700r4 small world yes just north of DeKalb. On the same subject I put that 400 in a work truck of a friend and had used the 400 cross member I am Not sure but may have the 700 crossmember from that yet.

03-06-2007, 11:01 PM	#8
SulphurDave Registered User Join Date: Sep 2006 Location: Sulphur, LA Posts: 259	Re: Trying to swap the 700r4 I went from 700r4 to th350 and all i did was cut that part off in your pic that wraps around the frame on the driver's side and made it look like the passengers side, slid it up some, everything matched up except for 2 holes on the driver's side in which i drilled new holes and voila.

03-07-2007, 12:15 AM	#10
MylilBowTie Right turn Clyde Join Date: Nov 2002 Location: Cincinnati, Ohio Posts: 2,911	Re: Trying to swap the 700r4 700r4 and th350c are both lockup transmissions. I have also cut the extra off on the stock crossmember. I made it where the crossmember went inside the frame rails and not inside / outside. Had to drill one bolt hole, I went from a th350c to a th400. If you don't want to cut it look for a double hump crossmember out of a 3/4 or 1 ton. Only draw back would maybe the way the exhaust is ran. Just looking at the one picture it might clear and not need to be ran different. __________________ 1974 C25 LWB: 454 4bbl Carb / TH400 / 3.73 1992 Camaro RS 305 TBI

03-07-2007, 04:32 PM	#12
MylilBowTie Right turn Clyde Join Date: Nov 2002 Location: Cincinnati, Ohio Posts: 2,911	Re: Trying to swap the 700r4 Just that, a th350c is a lockup torque convertor as well as a 700r4. Some may or may not know that. Trying to help sorry you took offense to it for some reason. th350c isn't any weaker than a regular th350. But a good torque convertor is going to run a good bit more money. I went to a th400 because I couldn't find a th350 that would hold up in my 84. I tried four different ones and they didn't suit me. At any rate Ive had bad luck with them. One of the th350s I had rebuilt the rest was used. It does take more power to run. But I rather have something I don't have to worry about making it home. __________________ 1974 C25 LWB: 454 4bbl Carb / TH400 / 3.73 1992 Camaro RS 305 TBI

03-07-2007, 08:46 PM	#13
pnkflyd850 Registered User Join Date: Feb 2007 Location: Newnan, Ga Posts: 5	Re: Trying to swap the 700r4 yea, it's just a regular th350..I tried searching junk yards for different trucks and I keep finding the same crossmember. So I may just cut off the end that rides up the side of the frame and make it flat just like the passenger side as 'sulphurdave' said. Thanks again everyone



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.