THD400 trans swap for auto with OD
Thread Starter
Drifting
Joined: Nov 2002
Posts: 1,951
Likes: 1
From: Shore NJ
THD400 trans swap for auto with OD
Good fall/winter project, I'd like to swap the THD400 trans to an auto trans with overdrive. I'd like to cruise with the others but with the 3 speeds it's too much rpm's and don't want to change out the 3:55 rear. looking for some info on what trans others have installed and what vendors you have used to get a good trans from.
Thanks for any info you can supply me with...
Thanks for any info you can supply me with...
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
Originally Posted by 73jst4fun
Good fall/winter project, I'd like to swap the THD400 trans to an auto trans with overdrive. I'd like to cruise with the others but with the 3 speeds it's too much rpm's and don't want to change out the 3:55 rear. looking for some info on what trans others have installed and what vendors you have used to get a good trans from.
Thanks for any info you can supply me with...
Thanks for any info you can supply me with...
Do a search for TH200R4 and TH700R4. Both are the overdrives you will want to install. I'm going with a 200 since it's more of a direct bolt on, and has a taller 1st gear for better take off. For your ratio, I would also suggest the 200. If you have a high HP motor, maybe look into the 700. There is a company in Cali, called Bowtie, that sells the whole kit and a rebuilt. They will give you all the info you need.
Safety Car
Joined: Dec 2005
Posts: 4,270
Likes: 20
From: Central Michigan
Thread Starter
Drifting
Joined: Nov 2002
Posts: 1,951
Likes: 1
From: Shore NJ
Thanks Durango and 682 for the info, looks like that's the popular company to go with....
682, a few questions for you....how was their kit to install and how much of a differance did the trans make. Does the 200 let you use your existing crossmember?, and do you need a new drive shaft? looks like to 200/level 2 like you recommended is the way to go. Did the kit for the center console match up looks wise?
Thanks again...
682, a few questions for you....how was their kit to install and how much of a differance did the trans make. Does the 200 let you use your existing crossmember?, and do you need a new drive shaft? looks like to 200/level 2 like you recommended is the way to go. Did the kit for the center console match up looks wise?
Thanks again...
Last edited by 73jst4fun; Sep 18, 2006 at 01:58 PM.
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
Originally Posted by 73jst4fun
Thanks Durango and 682 for the info, looks like that's the popular company to go with....
682, a few questions for you....how was their kit to install and how much of a differance did the trans make. Does the 200 let you use your existing crossmember?, and do you need a new drive shaft? looks like to 200/level 2 like you recommended is the way to go. Did the kit for the center console match up looks wise?
Thanks again...
682, a few questions for you....how was their kit to install and how much of a differance did the trans make. Does the 200 let you use your existing crossmember?, and do you need a new drive shaft? looks like to 200/level 2 like you recommended is the way to go. Did the kit for the center console match up looks wise?
Thanks again...
I can help with that too. The 200 will allow for use of the original cross member but you will have to move it forard a little to mate up right. Drill your own holes and you're in business.
The stock driveshaft will go right in place.
Depending on the kit, it will only affect the detent rail, not the shift lever. It will give you that extra 'click' in the selector and come with it's own lens to show the extra position.
Safety Car
Joined: Aug 2001
Posts: 3,681
Likes: 200
From: Waterford Mi
Safety Car
Joined: Dec 2005
Posts: 4,270
Likes: 20
From: Central Michigan
Going from a 400 to 200R4 you don't need to move the xmember.
Driveshaft will fit, but you need another yoke and combination U-joint
Shifter kit includes detent plate(bolts to side of shifter), indicater, and brackets to mount your cable onto the 200
Before the install, I ran a 383/T400/3:73 70 mph@3500 rpm, now running it at 2200rpm, big difference
BTO can tell you everything you'll need. Seems my bill came to a shade over $1800 for everything except U-joint, fluid, and beer
Theres a series of tests you have to run before the warranty is activated, I think they're on the website
Driveshaft will fit, but you need another yoke and combination U-joint
Shifter kit includes detent plate(bolts to side of shifter), indicater, and brackets to mount your cable onto the 200
Before the install, I ran a 383/T400/3:73 70 mph@3500 rpm, now running it at 2200rpm, big difference
BTO can tell you everything you'll need. Seems my bill came to a shade over $1800 for everything except U-joint, fluid, and beer
Theres a series of tests you have to run before the warranty is activated, I think they're on the website
Safety Car
Joined: Dec 2004
Posts: 4,071
Likes: 0
From: San Diego CA
For a car that weighs a little over 3000 lbs. the 2004R is by far the best bet. I don't think I've heard a horror story about them going out yet. I've heard tons of stories about the 3/4 clutch pack on the 700R4s going out so I'd definitely shy away from that. A 700R4 is better for something like a truck or a very heavy car. It's rather overkill in a vette and the first gear on it is so short that it's just plain annoying, in my opinion. My '95 Z28 had the 4L60E which is basically the computer controlled version and I remember it could only go like maybe 40 or so in first gear with 2.87 rear gears. Then it'd drop in to second and feel like it was too low, in my opinion. The 2004R is much more evenly spread out.
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Thread Starter
Drifting
Joined: Nov 2002
Posts: 1,951
Likes: 1
From: Shore NJ
Leave it to the Forum for the best advise, thanks guys 
, I'm leaning towards the 2004R stage 2 trans, they sell a HD converter with 2200 stall which should work, I think it's a 12" converter. A few other options to consider: a deep pan @ $175., I have a trans cooler already and a Moroso deep pan on the THD400, too bad the pan doesn't fit. I dont know the weight differance between the THD400 vs. the 2004R but will use the stock crossmember. They offer a flexplate so I dont know if the stock 168 tooth plate mates with the new converter.....
It almost sounds like a weekend project (without hitches but we know how that goes) I'm sure I'll have more questions....
, I'm leaning towards the 2004R stage 2 trans, they sell a HD converter with 2200 stall which should work, I think it's a 12" converter. A few other options to consider: a deep pan @ $175., I have a trans cooler already and a Moroso deep pan on the THD400, too bad the pan doesn't fit. I dont know the weight differance between the THD400 vs. the 2004R but will use the stock crossmember. They offer a flexplate so I dont know if the stock 168 tooth plate mates with the new converter.....It almost sounds like a weekend project (without hitches but we know how that goes) I'm sure I'll have more questions....
Safety Car
Joined: Dec 2005
Posts: 4,270
Likes: 20
From: Central Michigan
I'm using a 168 flexplate I got from Summit, it has the dual pattern converter hole pattern on it. If you've bought a flexplate within I'd say the last ten years or so, I'd say your OK, it should have both hole patterns.
Don't know about the weight, but I know it's freaking heavy
Picked up my 200 by myself(dry, no converter), off the tailgate and down to the floor, I'd say maybe 140-150 lbs? Don't want to do that again
With two people no problem
Don't know about the weight, but I know it's freaking heavy
Picked up my 200 by myself(dry, no converter), off the tailgate and down to the floor, I'd say maybe 140-150 lbs? Don't want to do that again
With two people no problem
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
Originally Posted by 73jst4fun
It almost sounds like a weekend project (without hitches but we know how that goes) I'm sure I'll have more questions....
Melting Slicks
Joined: Jul 2004
Posts: 3,248
Likes: 48
From: westland mi
Originally Posted by 73jst4fun
Leave it to the Forum for the best advise, thanks guys , I'm leaning towards the 2004R stage 2 trans, they sell a HD converter with 2200 stall which should work, I think it's a 12" converter. A few other options to consider: a deep pan @ $175., I have a trans cooler already and a Moroso deep pan on the THD400, too bad the pan doesn't fit. I dont know the weight differance between the THD400 vs. the 2004R but will use the stock crossmember. They offer a flexplate so I dont know if the stock 168 tooth plate mates with the new converter.....
It almost sounds like a weekend project (without hitches but we know how that goes) I'm sure I'll have more questions....
, I'm leaning towards the 2004R stage 2 trans, they sell a HD converter with 2200 stall which should work, I think it's a 12" converter. A few other options to consider: a deep pan @ $175., I have a trans cooler already and a Moroso deep pan on the THD400, too bad the pan doesn't fit. I dont know the weight differance between the THD400 vs. the 2004R but will use the stock crossmember. They offer a flexplate so I dont know if the stock 168 tooth plate mates with the new converter.....It almost sounds like a weekend project (without hitches but we know how that goes) I'm sure I'll have more questions....
Last edited by rosslato; Sep 18, 2006 at 05:04 PM.
if he orders it today he might be lucky to get it in a month from now!
Instructor
Joined: Feb 2006
Posts: 118
Likes: 25
From: Killearn Scotland
73jst4fun said;
That sounds a good choice.
I have just replaced a 700R4 with a TKO-600 in my '76.
I have to say though, the manual is brilliant, a close second to the 383 motor for best modification!
Good luck,
Douglas
I'm leaning towards the 2004R stage 2 trans, they sell a HD converter with 2200 stall which should work, I think it's a 12" converter
I have just replaced a 700R4 with a TKO-600 in my '76.
- I found 1st too low (with 3.08 rear).
- I could never get the damn thing to stop kicking down to third at 3/4 throttle (despite installing the kit, and having it checked by a transmission shop).
- I had trouble getting a B&M Holeshot 3000 converter to stay locked. It's a 10" converter and kept slipping once everything was up to temperature. Just too small a friction surface. So ended up with the standard converter and manual shifted when I wanted to 'drive' the car .
I have to say though, the manual is brilliant, a close second to the 383 motor for best modification!
Good luck,
Douglas
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
Originally Posted by 682XLR8
That's about how long it took mine
Am I the only one looking for a good one from a yard? I figure if I can find a gem out of a running car with low miles, I'll check it out, install a trans kit, and go with it. I don't do much hard racing, mostly cruising. When it needs rebuilt later, then I'll spend the $600 or so it'll take for the rebuild.
Safety Car
Joined: Dec 2005
Posts: 4,270
Likes: 20
From: Central Michigan
Yeah, probably
JK
Actually I wanted an entire kit to take the guesswork out of the installation, tuning, etc.
If someone knows what their doing, and/or wants to take the time to piece it together, thats
after all, thats how these swaps got started
JKActually I wanted an entire kit to take the guesswork out of the installation, tuning, etc.
If someone knows what their doing, and/or wants to take the time to piece it together, thats
after all, thats how these swaps got started
Thread Starter
Drifting
Joined: Nov 2002
Posts: 1,951
Likes: 1
From: Shore NJ
Originally Posted by rosslato
Jay, i did this switch last year w/the 200r4 level 3. the 200 weighs in around 50 lbs less. yer stock flex plate will work and so will your converter cover w/a lil cutting and your stock crossmember fits perfect although i did have to notch mine a lilttle to get to the rear tranny bolt but others didn't have to notch it. i also put a trans temp gage in my center cluster to keep track of the tranny temp along w/a B&M trans cooler. i have the 3:70 gears & cruise 2200rpm at 70 now. send me an email if u have any more ?'s.
what exactly did that cheapo inspection cover do and what did you replace it with?....