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Would like to install gm 4.3l v6 and th700r4 in my cj7.. What are costs? Issues?

Would like to install gm 4.3l v6 and th700r4 in my cj7.. What are costs? Issues?
I checked to see if i could locate any tag or number on either of the diffs. I found one on just the front diff.. (Tag reads: 5354908 3 54 & 46-13) I don't know what that means. Would you? :p
And then, I searched through old pictures of when I changed the gear oil and diff covers. I found a few pictures. Could you tell by the pictures what gear ratio the rear is? And if the front matches the tag? :confused:
THANKS AGAIN for your help! :notworthy:

If the front diff tag is correct, according to the internet, the front gear ratio is 3.54 (what ever that means.) :0

:)
76.........Good find. And Hopefully there the same at both ends....It is a good Idea to count the teeth if you still have the cover off just to verify.......seen folks do some strange things with those ID bands.

As mentioned that is a more suitable to Highway driving gear ratio.......If some off road was in your future , then you may want to consider a 3.15 gear for your Transfer Case that now has a 2.0 gear in it.......this would be a major improvement but only when the Transfer Case is in the low Range..........Your Freeway gears will still be the same once in High Gear when the Ratio at your Transmission is 1:1 and your rear axle at 3.54.

:D:D:D:D
 
:)
76.........Good find. And Hopefully there the same at both ends....It is a good Idea to count the teeth if you still have the cover off just to verify.......seen folks do some strange things with those ID bands.

As mentioned that is a more suitable to Highway driving gear ratio.......If some off road was in your future , then you may want to consider a 3.15 gear for your Transfer Case that now has a 2.0 gear in it.......this would be a major improvement but only when the Transfer Case is in the low Range..........Your Freeway gears will still be the same once in High Gear when the Ratio at your Transmission is 1:1 and your rear axle at 3.54.

:D:D:D:D

SWEET! That's what I wanted! I hope to make it my daily driver.. Use it occasionally off road and always in the snow.. But mostly dd. :notworthy:
Nope.. These were some old pictures I took a few years ago when I changed the gear oil. How many teeth should the diffs have? Do I count the biggest ones on the outside or smaller ones? :rolleyes:
 
3 54 & 46-13 ....... 46 (teeth on the ring gear) divided by 13 teeth on the pinion gear = 3.5385 or 3.54

3.54 gears are a very nice intermediate gear. Where a 4.11 gearing is an off road or drag racing or power gear. A 2.73 (found in newer CJ's) is a road gear or a gear generally found in a family car. At any given speed a 2.73 geared vehicle will run at much lower RPM's than a 4.11 geared vehicle. It's easy to see where a 2.73 geared vehicle will generally give higher/better mileage than a 4.11 geared vehicle. Also, a 4.11 geared vehicle will have more power or will pull better than a 2.73 geared vehicle. Naturally both axles should have the same gearing and a 3.54 gear set is was very common in your vehicle year.

I hope this helps.

Thanks Hedgehog! Helps a LOT! But still have questions... Like. is the 46 teeth on the ring gear... Mean on the flexplate? AND what/where are the pinion gear? :confused::o
Thanks still learning... :notworthy:
 
The numbers are 100% related to the differential gearing. The pinion gear is the tapered one the driveshaft turns. The ring gear is the larger gear turned by the pinion gear. The ring gear turns the carrier (the part that holds the ring gear) which turns the axle shaft and wheels. This would be the final drive ratio. It can be changed, but it's expensive to have someone do it for you. I suppose there is one more gear and that would be your tires on the road. Simply put, change your tires and you change your final gearing. 3.54 gears combined with a bigger tire might make a decent road gear. If you have stock tires they would be good off road gears. I run no bigger than 31" tires so my 3.73 gears make my V8 turn at an uncomfortable RPM rate while on the highway. Since I just changed my gear ratio from 3.73's to 3.31's I could write a book on this subject. You need to get a real honest to goodness shop manual and to back it up something like a Haynes manual. The Haynes manual isn't nearly as good as the shop version, but it covers many years and occasionally you find parts from different years on a CJ.

The Flex plate is the interface between the engine and Transmission . Yes it also has a ring gear for the starter to engagement. That ring gear has nothing to do with drive gear ratios.

There are many places where gear ratios are talked about, but each is generally referred to on it's own, IE Transmission ratios, Transfer Case ratios and differential ratios. Of course the Transmission ratios change with the gear you are in and the Transfer Case has high and low ranges, the differential gears don't change. In big a work vehicles like a semi or dump truck you often find two speed differentials. I often thought that a 4x4 would be well served by having a two speed rear end or differential. Wouldn't it be great to have both off road final gearing and highway gearing in your jeep or other off road/highway vehicle.
 
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The numbers are 100% related to the differential gearing. The pinion gear is the tapered one the driveshaft turns. The ring gear is the larger gear turned by the pinion gear. The ring gear turns the carrier (the part that holds the ring gear) which turns the axle shaft and wheels. This would be the final drive ratio. It can be changed, but it's expensive to have someone do it for you. I suppose there is one more gear and that would be your tires on the road. Simply put, change your tires and you change your final gearing. 3.54 gears combined with a bigger tire might make a decent road gear. If you have stock tires they would be good off road gears. I run no bigger than 31" tires so my 3.73 gears make my V8 turn at an uncomfortable RPM rate while on the highway. Since I just changed my gear ratio from 3.73's to 3.31's I could write a book on this subject. You need to get a real honest to goodness shop manual and to back it up something like a Haynes manual. The Haynes manual isn't nearly as good as the shop version, but it covers many years and occasionally you find parts from different years on a CJ.

The Flex plate is the interface between the engine and Transmission . Yes it also has a ring gear for the starter to engagement. That ring gear has nothing to do with drive gear ratios.

There are many places where gear ratios are talked about, but each is generally referred to on it's own, IE Transmission ratios, Transfer Case ratios and differential ratios. Of course the Transmission ratios change with the gear you are in and the Transfer Case has high and low ranges, the differential gears don't change. In big a work vehicles like a semi or dump truck you often find two speed differentials. I often thought that a 4x4 would be well served by having a two speed rear end or differential. Wouldn't it be great to have both off road final gearing and highway gearing in your jeep or other off road/highway vehicle.

Good to know hedgehog. Looks like I have a lot of research to do. :p


Any suggestions on which motor mount go go with? I was looking at the Transdapt 4100.... Perhaps if you don't have experience with it someone else may. :chug:
 
Motor mounts ... sorry I can't help much there. Way back when I did my V6 conversion I got my motor mounts from NOVAK. They were simple weld on/bolt on items, but they worked very well. If I were you I'd haunt the Advanced Adaptors and NOVAK pages. These guys have done this for a very long time and they have all the answers for a practical swap.
 
M.O.R.E. would be another place for the mounts. People on the net. seem to have good things to say about them.
My cj came with a worn out 305, the PO said the mounts were from AA (but I don't know if he was right or not, and would have been 20 years ago) they were not built very strong IMO.

I ended up making these. Here's a shot of the old mount and the (than new) home made. Sorry but these are the only pic's I have.

IMG_1066_800x600.webp

IMG_2460_800x600.webp
 
Okay Guys.. I found some motor mounts off ebay for transdapt 4100... What do you think? They only want $66 for the pair -which includes the pads, brackets and hardware...


THANKS FOR YOUR CONTINUED HELP! :notworthy:
 
M.O.R.E. would be another place for the mounts. People on the net. seem to have good things to say about them.
My cj came with a worn out 305, the PO said the mounts were from AA (but I don't know if he was right or not, and would have been 20 years ago) they were not built very strong IMO.

I ended up making these. Here's a shot of the old mount and the (than new) home made. Sorry but these are the only pic's I have.

Nice work there Old Dog! Thanks for the pictures too that helps.. Even though I'm thinking about installing the 4.3l.:o
 

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