Driveshaft Length

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

tstepp920

tstepp920

Joined
Apr 24, 2016
Threads
364
Messages
2,977
Location
Fayetteville, North Carolina
Can someone that has done the H55 conversion in their FJ40 tell me what their rear driveshaft length ended up being. I plan on installing an OME suspension with 2 1/2" of lift in the springs. The is a 21" long double Cardan driveshaft for sale on CL and I am wondering if it will fit.
 
If I remember correctly, the shaft is about 18" with a H55 splitcase combo, maybe a bit shorter with the split case drum brake.

Dyno
 
I think 18" is probably right. My rear driveshaft is 22.5" fully compressed and the 5th gear spacer is 3.5', so I'd say 19" is the maximum. 21' will be too long. With the H55 installed in my '82 with no ebrake drum, the distance between the diff and the T/C is about 19.25, so I'd guess I'm going to have to shorten it to about 18" just to get it installed over the studs.
 
billmc said:
I think 18" is probably right. My rear driveshaft is 22.5" fully compressed and the 5th gear spacer is 3.5', so I'd say 19" is the maximum. 21' will be too long. With the H55 installed in my '82 with no ebrake drum, the distance between the diff and the T/C is about 19.25, so I'd guess I'm going to have to shorten it to about 18" just to get it installed over the studs.
Click to expand...

Transfer case has studs and rear axle uses nuts and bolts. Install the transfer case side first would solve that issue. But compression of the springs you certainly have have enough length to accommodate that. Hoping the location of the transmission is the same in the BJ42 as in the FJ40. Should have a H55F setup from a BJ42 including drivelines in a few weeks. My plan is buying the drivelines and already shipping a pallet that I will come out ahead over having to modify my 82 drivelines.
 
Living in the Past said:
Transfer case has studs and rear axle uses nuts and bolts. Install the transfer case side first would solve that issue. But compression of the springs you certainly have have enough length to accommodate that. Hoping the location of the transmission is the same in the BJ42 as in the FJ40. Should have a H55F setup from a BJ42 including drivelines in a few weeks. My plan is buying the drivelines and already shipping a pallet that I will come out ahead over having to modify my 82 drivelines.
Click to expand...

Of course you're right. I forgot that the diff end has bolts. Even still it was difficult for me to remove my rear driveshaft because it was so tight. Perhaps it was over greased in the past and couldn't compress as far as it should, but I'm still worried about having it short enough for full spring compression. I really don't know about the BJ42, but my FSM shows the frames the same, including the transmission member. It'll probably work fine. I'm planning to cut and weld mine myself, so we'll see how that goes.:hillbilly: Also before I cut anything, I need to determine if the drive plate for a cable/FF diff will be in the same position or closer than a SF diff, since that will be my end config.
 
billmc said:
Of course you're right. I forgot that the diff end has bolts. Even still it was difficult for me to remove my rear driveshaft because it was so tight. Perhaps it was over greased in the past and couldn't compress as far as it should, but I'm still worried about having it short enough for full spring compression. I really don't know about the BJ42, but my FSM shows the frames the same, including the transmission member. It'll probably work fine. I'm planning to cut and weld mine myself, so we'll see how that goes.:hillbilly: Also before I cut anything, I need to determine if the drive plate for a cable/FF diff will be in the same position or closer than a SF diff, since that will be my end config.
Click to expand...


Never gave the FF rear any thought it would be different. Going the same route. Not sure if mine is from a short wheel base or mid wheel base. Mine does not have tabs for a swaybar. Not sure if mid wheel base had a swaybar. My plan was to go E-locker front and rear. Haven't been able to locate a reasonably priced E-locker for the front. Not sure if there is a difference in the 80 series diff. Think one is 4.10:1 and the other is 4.11:1. If so that would be a mix match when in 4WD.
 
Living in the Past said:
Never gave the FF rear any thought it would be different. Going the same route. Not sure if mine is from a short wheel base or mid wheel base. Mine does not have tabs for a swaybar. Not sure if mid wheel base had a swaybar. My plan was to go E-locker front and rear. Haven't been able to locate a reasonably priced E-locker for the front. Not sure if there is a difference in the 80 series diff. Think one is 4.10:1 and the other is 4.11:1. If so that would be a mix match when in 4WD.
Click to expand...
I'm transferring the front and rear cable lockers from an HJ61 into my 40 eventually. I've recently heard that they're 3.70, always thought they were 4.11s. They're currently on my 62 rust bucket. I'm assuming they're the same dimensions as a late 40 semifloat but I ought measure next chance I get.
 
When I get back to the garage; I can measure my drive shafts for you.... when I bought the truck, it was on stock springs & had an H55F. I've since installed a 2.5 inch OME lift, full floating rear axle & cable lockers. I didn't modify the drive shafts since it was already set up for the 5-speed. The rear drive shaft had a double Cardin joint at the transfer case end.

Not sure I understand how a FF & cable locker will change things. The axle position is the same whether it's a semi-floater or full floater. The cable locker flange is in the same place as the standard 3rd member. I'm going to bet those cable lockers are 4:11's & there's a long splined inner axle you're missing to swap the setup into a set of 40-series axles.
 
Last edited:
SuperDuperCruizer said:
When I get back to the garage; I can measure my drive shafts for you.... when I bought the truck, it was on stock springs & had an H55F. I've since installed a 2.5 inch OME lift, full floating rear axle & cable lockers. I didn't modify the drive shafts since it was already set up for the 5-speed. The rear drive shaft had a double Cardin joint at the transfer case end.

Not sure I understand how a FF & cable locker will change things. The axle position is the same whether it's a semi-floater or full floater. The cable locker flange is in the same place as the standard 3rd member. I'm going to bet those cable lockers are 4:11's & there's a long splined inner axle you're missing to swap the setup into a set of 40-series axles.
Click to expand...

Thanks for the info! As I say, I was assuming that the axles were the same, but it's great to have the confirmation. I've always thought that the axles were 4.11s, but in a recent thread someone pointed out that all Japan-spec HJ61s came with 3.7s. In the end either ratio is fine by me. Yes, before I make the swap I need to source a long side FF axle, since Toyota only has the short side. If you have a line on a source, I'd love to hear it!

Best,
Bill
 
@billmc there's no absolutes when it comes to Toyota's configurations and these trucks. You may indeed have 3.7's as for the long splined axle you're looking for... I can get you measurements. I have a spares for the front & rear just in case I break something.
 
SuperDuperCruizer said:
@billmc there's no absolutes when it comes to Toyota's configurations and these trucks. You may indeed have 3.7's as for the long splined axle you're looking for... I can get you measurements. I have a spares for the front & rear just in case I break something.
Click to expand...
Thanks, the measurement for the long side rear would be great. Another one of my assumptions is that when I swap the FF front diff, the existing axles will work fine, and that it's only the long side rear that I need.

btw- Apologies to the OP for this little hijack.
 
Fully compressed... from the face of the 3rd member flange to the transfer case flange (double Cardin side):

IMG_4404.webp


IMG_4405.webp
 
Are you planning enough lift you feel the need for a double cardan on the back? When this thread started my H55F from a BJ42 was still in transit. I now have the transmission and the original drivelines if you want any stock measurements.
 
OME 2 1/2" lift. Not sure. Reading different threads seems to go back and forth. Exploring options.
 
I am still waiting on mine. (H55F and transfer case from a BJ42 also). If you would hurry up, work out all the kinks, and post a pic heavy thread I could quit sweating all this details. Get a move on.
 
tstepp920 said:
I am still waiting on mine. (H55F and transfer case from a BJ42 also). If you would hurry up, work out all the kinks, and post a pic heavy thread I could quit sweating all this details. Get a move on.
Click to expand...

My biggest hold up is I do not have the correct input shaft yet. Plus my 79 FJ40 and H55F are about hundred and fifty miles apart. I have a skid plate from a 82 FJ40 with a four speed and one from the 83 BJ42 with a five speed. The mounting holes and hole to clear rivets in the frame are in the same location. Now I need to measure the holes and rivets in the frame to the ones in the 79. Off course the two frame are in two different locations. If the rivets at least are in the same location would make installing the skidplate a breeze. The biggest challenge is going to be figuring out how to deal with the difference between the 79 inspection cover footprint with that of the 83 inspection cover.
 
Came off my BJ42... previous owner swapped in an H55F and until recently, I believed these were stock drive shafts for a 5 speed equipped 40. The drivetrain was quiet.
 
SuperDuperCruizer said:
Came off my BJ42... previous owner swapped in an H55F and until recently, I believed these were stock drive shafts for a 5 speed equipped 40. The drivetrain was quiet.
Click to expand...


Five speed was only available on the 83/84 models and can not find any FJ40 or BJ42 that show a double cardan drive shaft front or rear. Checked on the front drive shaft from the 84 HJ47RV I bought from a wreck. It had a double cardan in the front drive shaft. Depending on market they did have a double on the front drive shaft. Did that to verify the parts diagram would show the double cardan including the break down. The front drive on the HJ47 isn't that short so not sure why it had one but appears to be stock. Curious if your BJ42 had a lift. Such a short rear driveline and lift might explain the double cardan.
Located my 82 FJ40 drivelines today. I compared them to the five speed drivelines. The four speed drivelines need to be modified. Think I have a set of four speed drivelines from 74-80 that I want to compare the ones from the 82. Seen them list as being the same. The 74-80 had the one piece transfer case with a hand brake. The 82 has a split transfer case and no hand brake. Curious if they are the same or close enough they will work on either.
 
You must log in or register to reply here.

Share this page

Back
Top Bottom