i have been searching for quite some time with no luck. on my 2wd truck i have the 7.5" ring gear i am trying to figure out if the 7.5" rear axle shafts are the same as the 8" shafts. basically what i'm hoping to do is put a 4wd axle in and re use my 2wd shafts to retain the 5 lug pattern. I know that the 7.5" front diff has a different spline count than the 8" rear. however i have not found anything regarding the 7.5" rear.

if it is not possible to swap what is available for the front for a 5-6 lug conversion.

now as far as i know the highest gear ratio in a 2wd 8 inch rear is 4.10 im looking for 4.30 or 4.56 ratio availability of 4wd rears are much more common as well.

another option i know that i have is to get a 4wd axle and 2wd 8 inch shafts but that is yet another item to purchase. (still less than 6 lug conversion and 4 new rims getting tires swapped ect)

I think i would rather go 8 inch rather than re-gear my 7.5 becouse this truck very well may get sas'd at some point if i come across a donor vehicular for the right price. if i go sas then all i would have to do is swap back to 6 lug shafts (witch i would already have from the donor axle)

I know that i will have to weld new perches on to sua on a 4wd axle swap i will probably sua and 63" chevys when i swap rears easy to swap back to a soa if i go sas later. will probably even leave the soa perches on the axle if i can.

 

you could always run 6 to 5 lug adapters. i have some on the rear of my truck right now until i get new wheels for the back.

 

that makes more sense than 5 to 6 lugs on the front, how far do the adapters space the wheels out, im not running flared fenders and don't want my tires sticking out too far.

how do your 4.10 feel with 31's im running 31's now but thinking i wanna go with a deeper gear for down the road. my truck gets around surprisingly well for 3.27 gears but lacks some gear

 

Rear 2wd are 27 Spline and are a few inches shorter than 4wd axles.

The 2wd shafts will not work in a 4WD axle.

 

What's the length of the 4wd axle shafts? I'll measure the 5-lug ones I have which are the same spline count as the 4wd shafts. Maybe OP can go the route of buying the same shafts as me (They're about $150/ea from Toyota, OP) and use those? 4wd 3rds definitely work in 8" 2wd housings.

 

spline count is different 27 for 2wd 30 for 4wd.


if it was me, i'd regear the rear 3rd member that you already have... it would be much easier than swaping in a new housing / axles / running adapters. buy up to 5.29s for the 7.5" front diff for an IFS truck but have someone throw it in your 2wd rear..

 

From toyotapartszone.com

30 spline 5-lug axle shaft part number: **311-35430
27 spline 5-lug axle shaft part number: **311-35450

Def. sure about the 30 spline shafts existing, that's what they say are for my VIN.

 

id rather go 8 inch because if i go sas later i don't want to do the rear gears twice. if someone has a set of 8 inch 4wd shafts someone could measure and magnusian could measure his. i want to go to 63" and get rid of my add a leafs so my truck wont ride like a old 1 ton ford so the rear axle is coming out anyway.

 

i can measure an IFS 4x4 axle shaft when i get home tonight.

 

There are 2WD rear axles with the 8" diff. but still 5-lug axles and spring under. Sort of uncommon, but they are out there. I knew a guy (used to post here many years ago) with a ~'85 2WD pickup that had the 8" rear. Wasn't a special 1 ton pickup or anything.

 

yup i had one under a 79 Toyota motor home i was gonna yank the axle out and throw my 7.5 under the motor home before i sold it. but ran short on time and had to make room in my driveway when i went to a larger boat, didn't have time to get it done. kinda regret not getting that rear end pulled out.

tofer if you could do that it would be much appreciated. Magnusian is rebuilding his 2wd 8 inch rear right now so it would be a great time to get a comparison measurement.

 

when i had the 4.10's with the 31's it felt pretty good. had decent acceleration and mpg wasnt bad. could get it up to 90 and still had some rpm left. i need to update my sig though because now i have a trd elocker axle with 4.88 and it screams up to 70 but there isnt much left after that and my mpg went to hell. once my 31's are shot, i plan to go up to 33's.

 

^^ I forget, which transmission do you have?

I can't measure my shafts until the weekend but I will do! Ez, also I've been "rebuilding" my rear axle for what seems like the better part of a year now, probably gonna be a month or two before it's reassembled anyways though the brakes go on as soon as the dealership gets my new studs in. One thing though, if we do find out that you can use the 30 spline 2wd shafts in a 4wd rear axle housing you probably can't use the 4wd drum setup, which means you'll have to do the entire rear brake setup at the same time you do the axle shafts. I HIGHLY suggest not going with drum brakes as the cost will end up being the same or more than doing a disc brake conversion. If I'd known before I started buying parts for the rear brakes (and before I knew I needed new backing plates) I would've gone with discs because I've easily sunk a grand into the brakes alone on this heap. It would probably be easier to try to find a 4spd 2wd being parted out since you should be able to grab the whole axle and then just drop in a 4wd diff with gearing of your choice already in it.

If someone could get a snap of 4wd bearing cases for the rear then we could know for sure if this Frankenstein monster will work.

 

4.88 is a tall gear, i don't think i want to go quite that tall but a e locker would be awesome, ill have to check the j yards for one. im hoping to get in a 4.30 or 4.56 gear. i will be going 33's as well when these tires wear out. but i still have another year possibly two on them. i have yet to see pictures of pre tacoma 2wd's on 33's sounds like there will be two of them running around before long..lol i was doing some measurements today and with a small amount of trimming and hammering the pinch weld i should clear 33s where im at now.

i also noticed one side in the back is sitting about an 1 1/2 inchs lower than the other looks like one of my air shocks blew out need to get this rear suspension done right sooner rather than leafs was a temp fix that has lasted about 8 years...lol i added air shocks that i took off a vehicle i parted out a couple years ago because i was still squatted in the back.

Magnusian measurements would be much appreciated will make great reference material for others later on as well.

 

I've been doing some googling, actually looking to see if anyone out there makes aftermarket 5-lug shafts (apparently not, I mean, c'mon, how hard is it to drill the holes in a different spot) and have come across a few posts on sites of unknown reliability that suggest that the 30 spline 2wd shafts are the same length as the 4wd shafts and that they're the same shafts as the 1-ton and v6 2wds. Also found a place that sells replacement bearing cases and have shot them off an email with the part number for the 2wd rear bearings and original bearing cases asking if they are compatible.

 

The 2wd 8" axle shafts are not the same length as the 4wd 8" axle shaft. The 2wd 8" axle shaft will work in any 8" pre-taco 3rd member. Your best and cheapest route would be to use a complete 4wd rear axle, redrill the flange for 5lug and then head to the junk yard and pick up two 4wd axle shafts when you do the SAS. Also remember the E-brake cable setup it totally different between the 2wd truck and the 4wd truck. The backing plates are different as well.

The Toyota dually rear axle that they use in motorhomes and U-Haul trucks have a unique axle. The 3rd member is just an 8" V6 3rd but the axle itself is a full floating rearend and has different axleshafts all together and they are not compatible with anything else. They are considered "1 ton" axles BUT Toyota did make a 1 ton truck with a regular axle meaning single rear wheels and it is just an 8" 2wd 5 lug rear.

James

 

thank you for the info not all the Toyota motor homes had the full float rear end though, they were suppose to all be replaced in a recall but the one that i had under my motor home was a non full float 5 lug 8 inch rear. the rim was a single rim with 4 lips to accommodate two tires on a single rim.

is the e-brake different enough were it requires different e-break cables. or is it all just inside the drum that its different, i would probably get my axle complete drum to drum. then re do the breaks seals and so forth.

 

I just went out and measured my 84-95 4WD PU 30 spline spare rears, and they're almost exactly/as far as I could tell 28.5" from tip to tip. Rumor is that 90-95 4Runners have a ~1/2" wider rear axle than 84-95 PUs, so their axleshafts would likey be ~1/4" longer. I have no way to verify that though.

Right you are! ALL Toyota 8" axles have 30 spline axleshafts, 2WD and 4WD front or rear.

 

79-85 4wd rear axles are narrower than the 86-95 4wd truck axles so they are not the same length.

James

 

You are correct. The Toyota motorhomes of 1986 and older had a 5 lug semi-float rear. Anything above that had full floaters.

James