Cummins 4BT & Diesel Conversions Forums banner

1 - 15 of 15 Posts

·
Registered
Joined
·
17 Posts
Discussion Starter #1
I have been reading about the transmissions and adapters the way it souds you can adapt any transmission to the 4bt if so can you use a 700r4 gm to this engine.
 

·
Administrator
Joined
·
1,447 Posts
Yes, A 700r4 has the same bolt pattern as a th400.
The transmission does, but NOT the torque converter! Smaller circle, only 3 bolts on the 700R4/4L60.. Folks have either done an adapter ring or modded torque converter to the TH400 circle.
 

·
Registered
Joined
·
500 Posts
The TH400 has a 11.5" diameter bolt pattern, 6 lug (for HD apps).
The 700R4 has a 10.5" diameter bolt pattern 3 lug.

You've got to either

1: modify the flywheel/mounting ring
2: modify your TC

I had a custom converter built, see the FAQ.
 

·
Registered
Joined
·
1,203 Posts
The TH400 has a 11.5" diameter bolt pattern, 6 lug (for HD apps).
The 700R4 has a 10.5" diameter bolt pattern 3 lug.

You've got to either

1: modify the flywheel/mounting ring
2: modify your TC

I had a custom converter built, see the FAQ.
i think it's 10.75" on the 700r4. I had a ring made for mine. It's worked for almost a thousand miles so far...
 

Attachments

·
Registered
Joined
·
500 Posts
i think it's 10.75" on the 700r4. I had a ring made for mine. It's worked for almost a thousand miles so far...
11.5" & 10.5" - Going by what my transmission guy said, 30 + years of experience. Only other dimension I can find is ~10-5/8" which is very close to what I was quoted.
 

·
Registered
Joined
·
1,203 Posts
11.5" & 10.5" - Going by what my transmission guy said, 30 + years of experience. Only other dimension I can find is ~10-5/8" which is very close to what I was quoted.
experience or not, my adapter has a 10.75" diameter on the converter bolt holes and bolts up to my 700r4 converter and has driven me 800+ miles. I just checked my drawing used for the CNC and measured the extra adapter I have sitting here.
 

·
Registered
Joined
·
500 Posts
Charlton Heston says....

experience or not, my adapter has a 10.75" diameter on the converter bolt holes and bolts up to my 700r4 converter and has driven me 800+ miles. I just checked my drawing used for the CNC and measured the extra adapter I have sitting here.
I don't dispute what you've measured on your setup. My research shows dimensions with 3 different numbers 10.5" 10.625" and 10.75" from various vendors respectively. Depending on where you measure from there could be some discrepancy. (ie center to center or edge to edge).


Here's two examples where measurements differ.
Ebay Item number: 200152096673
Ebay Item number: 160155029510

Until I see a guy like this carrying tablets where it's set in stone, I'm going go with approximately 10.5" :D
 

·
Registered
Joined
·
1,203 Posts
anyone who states a bolt circle diamater with anything other than center to center is just downright silly.

I would suggest to anyone that they make the measurement themselves and not trust any of us 100%, especially anyone on Ebay. It can be a difficult measurement to make on a 3 lug torque converter, I measured it and checked it and measured it again, eventually coming up with 10.75 which i then had cut out on a cnc and it lined up perfectly. Just my experience, take it for what it's worth :D
 

·
Registered
Joined
·
1 Posts
So from what vintage vehicle might one get a 700r4 from? I think it might be worth the hastle to get the OD tranny inplace of my TH400. Is the 4l60e the same bolt pattern also?
Thanks Troy

Laying the ground work for a transplant into a '70 chevy 1/2ton 2wd.
 

·
Administrator
Joined
·
1,447 Posts
4L60E is the same trans as 700R4, but electronically controlled.

700R4 - Get one 88 or later, or get whatever one you find updated to that standard. Better pump, internals, etc. Used in a LOT of GM stuff, especially 1/2 and 3/4 ton trucks w/ gas motors up until about 92. (My C2500 has one..)
 

·
Registered
Joined
·
75 Posts
I've put a 700r4 behind my 4bt. It is a unmodified 4bt in a stock truck. I have no adapters my ribbon band was "modified" with a $9 angle grinder cutting out every other hole to the inside so I have bolt "slots" instead of holes. The converter can be pulled forward to the flexplate up to 1/4" and still work Ok. The gap between the 700r4 converter and 4bt ribbon is "around 1/4" I used hardened washers as spacers to make the gap about 1/8". I bought longer grade 8 bolts for full thread engagement, lockwashers, and loctite. The guy I bought the motor from used this method without the washers on a big tube framed rig with 52" tires with no problems. If it blows up or works for a few hundred miles I'll post pics.
 

·
Registered
Joined
·
1,203 Posts
4L60E is the same trans as 700R4, but electronically controlled.

700R4 - Get one 88 or later, or get whatever one you find updated to that standard. Better pump, internals, etc. Used in a LOT of GM stuff, especially 1/2 and 3/4 ton trucks w/ gas motors up until about 92. (My C2500 has one..)
there are a lot of more subtle changes from year to year and between the 700r4 to 4l60e, but the 4l60e did replace the 700r4 in use. I'm pretty sure there were actually case changes between the pre 87 and the 87 and later model transmissions. Make sure you get one with a 30 spline input, the early ones have 27 spline and are not nearly as strong. I would try and start with a post '87 transmission if you can. If you get one out of a diesel it will have a usable converter and be usable in stock form, but not ideal IMO. if you get one out of a gasser, you will have to change the governer and the torque converter.

IMHO the 700r4 is an acceptable transmission in a vehicle that will not be seeing heavy towing. You shouldn't tow in OD with a 700r4 anyways. If you plan to tow a lot or are really hard on vehicles, I would recomend a 4L80E in place of it.
 

·
Administrator
Joined
·
1,447 Posts
1 - 15 of 15 Posts
Top