Limited slip for 3.07 gears??

[TBartlett1]

I just bought a 1990 W350 in California and drove it home to Mass.

Couldn't pass it up. My question is this, does anyone make a limited slip for an axle that has 3. 07 gears??

 

[MEby]

From what I here, yes. Where from I have no idea.

 

[Philip]

The 3:07 axles use the same carrier as a 3:54 axle. The 3:07 is a 35 spline axle. The 3:54 is a 32 spline.

 

["Mad Max"]

... so if I understand this right... yer saying if I have a '93 D70 (with a factory limited slip and 3. 54 gears in it) sitting around, and my daily-driver truck has a '91 D71 under it... ... . and I want to install the limited slip from the 70 into the 71... . I'd need to pull the axles and the carrier from the 70, take the 3. 54 ring gear off, bolt up the 3. 07 ring gear to the 70 carrier, then install the 70 carrier into the 71 housing, and then install the matching 70 axles in the 71 housing, and that's how it's done?? If so, sweet - I'll be doin' it.



- Sam

 

[TBartlett1]

My investigation found the the D70 with the 4. 10 & 3. 54 gears use the same carrier and differental housing, the D71 carrier and diff housing are different because of the larger offset needed to accommodate the larger pinion gear and are not inter-changeable.

tim

 

[Philip]

The carrier is the same between a 3:54 and a 3:07 axle.



The offset is in the axle housings.



I have a spare 3:07 carrier assy and a 3:54 L/S carrier on a bench. All mounting points are the same.

 

["Mad Max"]

Well crap... okay, this is interesting, and frustrating, because it contradicts some of what posted here, but here it is. I just got off the phone with Randy's and had a very interesting conversation with Brian in sales. Okay, here's his version of the voodoo -



Bottom Line - yes, a limited slip is available brand new for a factory D71 rear axle with 3. 07 gears. However, you won't be buying a 3. 07 lim slip unit... you'll be buying a 4. 56 lim slip unit, Here's what Brian said -



The 3. 07 r&p will not work in a D70 housing, only a D71. This is because of the 31/32" offset housing for the 3. 07s. Other offests are 1/2" and 5/8" but I'm not sure which are for what.



Second,... according to Randy's... the 3. 54 carriers will not work in the D71 housings, because the offset for a 3. 54/4. 10 ringgear is not set up for 31/32"; you'll need a 4. 56 carrier, because 4. 56 carriers have the same 31/32" offset, and therefore the 4. 56 carrier (and associated factory 'power lock' limited slip) unit is what they say we need to get a nice, new limited slip in our 3. 07-geared D71s.



The cost for both 'parts' (carrier unit and power lock guts - two separate part numbers) is $633. 70; $270. 26 for the carrier and $363. 44 for the guts. Important note - the 4. 56 carrier they have has the correct 32-spline internals to work with the D71 axle.



So... very interesting, and I'm confused compared to what you're saying Philip. Still doing some research, but one way or another I'll be doing this upgrade when I get the cash but that'll be a while as this mod is low on my priority list, but it is on the list.



I still haven't read any posts on several websites from anyone who has actually done this swap, so if noone gets to it before me then I'll be the guinea pigOo. .



... more to follow...



- Sam

 

[TBartlett1]

Good info "Mad Max"

Thanks Tim

 

[CValiquette]

Holy crap! I thought I drove mine far! I went from the northern tip of CA home to central TX. With no AC! In August! Never doing that again! Like you though, I couldn't pass up a good deal. How was your trip?

 

[Thierry]

I will disagree as I used a factory limited slip that had 3. 54 gears to my drive line shop and had him redo my rear end with 230000 miles 3 years ago. I gave him a spare set of 3. 07 gears and told him to use which ever was best.

He tried to get me a new set of gears as he thought they were easy to get and after calling around for 4 hours finally admitted to failure. He had to replace the guts on the limited slip as the splines were different . Total cost for the rebuilding the pumkin with new bearings, ship packs. alignment, new limited slip packs, new guts for limited slip, synthetic oil and limited slip slime was just over $500.

I now have over 260000 miles on the truck and love the rear end, I can now pull things and back up in loose dirt and not just spin my tires

 

[RSchwarzli]

I finally broke down and ordered the stuff from Randy's last week. Carrier and all. Cost me, but had enough dinking around with what will work and what might not. After many winters I think I will like this one a little better!



All going well, in the next week or so I will install it and will see how it works. Will let you know!



Robert

 

["Mad Max"]

I will disagree as I used a factory limited slip that had 3. 54 gears to my drive line shop and had him redo my rear end with 230000 miles 3 years ago. I gave him a spare set of 3. 07 gears and told him to use which ever was best.

He tried to get me a new set of gears as he thought they were easy to get and after calling around for 4 hours finally admitted to failure. He had to replace the guts on the limited slip as the splines were different . Total cost for the rebuilding the pumkin with new bearings, ship packs. alignment, new limited slip packs, new guts for limited slip, synthetic oil and limited slip slime was just over $500.

I now have over 260000 miles on the truck and love the rear end, I can now pull things and back up in loose dirt and not just spin my tires

Okay so to clarify, 3 yrs ago you had a truck with a D71 and 3. 07s that had 230,000 miles on it, and you took the truck to a shop to have it checked out, and you had a spare factory 3. 54 LSD carrier and a spare set of 3. 07s, and asked the shop to use both to 'augment' the D71 diff. In the process the shop used the 3. 54 carrier guts (splines and lim slip) and put them in the 3. 07 carrier, then they bolted up the 3. 07 ring gear, and installed the 'modified' 3. 54 carrier in the D71 housing with the original 3. 07 pinion? I just want to make absolutely sure, because that sounds exactly like what I had planned to do with Philip's posts.



So, if that's all correct, then it appears there's two ways to do this - one with 'factory' parts, and one with aftermarket parts, ja?



So does the 3. 54 carrier also have the 31/32" offset?



- Sam

 

["Mad Max"]

I finally broke down and ordered the stuff from Randy's last week. Carrier and all. Cost me, but had enough dinking around with what will work and what might not. After many winters I think I will like this one a little better!



All going well, in the next week or so I will install it and will see how it works. Will let you know!



Robert

Rob, did you get the 4. 56 version thing from Randy's? If so then we all may have two confirmed ways to do this Oo.



- Sam

 

[RSchwarzli]

Sam,



Been wondering the same thing all morning. I will have to check and see what I actually have.



How would I tell in this case what style I have?



Robert

 

["Mad Max"]

... man I have no idea - I've never had one apart/know what's really 'in' there... all my knowledge is just what I've read about or seen from the inside of a diff cover... and that ain't much . I talked to my local diff guy and he said the '4. 56 thing' doesn't sound possible... but Randy's is a reputable place... but so is my diff guy... . so I'm inclined to believe any voodoo I read about, especially when it's contradictory in nature. Voodoo typically sounds weird initially, and it almost always is, but some of it is so trick in nature that it ends up actually working when it shouldn't. So, I say let's see what you're getting and experiment a bit. I'd also call Randy's and make 100% certain they know what you're doing, and if it doesn't work out be sure they give you a solid return policy.



- Sam

 

[RSchwarzli]

Glad I am not the only one that does not know!



Secondly Sam, I thought you knew EVERYTHING there was to know about 1st gens!

 

[Philip]

The only difference in the 3:07 and 3:54 carriers is the spline count. The 3:07's have 35 spline axles. Most of the 3:54's use a 32 spline count.



I haven't seen a 3:07 without wedge locks.

 

["Mad Max"]

doggonit Phillip... now you got me real curious - tomorrow I'm pullin' the axles outta my '91 D71 and my '93 D70 and see how many splines they have

 

[TBartlett1]

The truck was driven home by my son & his girlfriend. The AC hose blew before they got outa Fresno & the windows didn't work. Fortunately these trucks have the wing for fresh air. His girlfriend put it in perspective, she said that our soldiers in Iraqi carry full gear in 120 deg + heat so they could do this. The truck ran fine till Ohio where the water pump failed. He pulled over to the side of the road & a Trooper was there within minutes and called a flatbed. He called me wondering what to do so I asked him what the local zip code was and found a NAPA dealer approx a mile from him. Called Napa & had them hold the part. The driver of the flatbed stopped at Napa he got the part and he also recommended a good shop to replace the water pump. From the time he knew he had a problem to the time he was back on the road was just over 2 hours. Very lucky!! Some of the places he went thru would have taken 2 or 3 days & big $$$ to get going.

I’m currently working on the new W350 installing new wheels & tires. I will get back to it after dinner.

I’ll post some pictures if I can figure out how?

 

[Philip]

Last night I picked up a 35 spline L/S carrier from a guy that is local. This carrier came out of a 90 W250 with 4:10 gears.



Looks like Dana might have just threw together parts to get axles to Dodge.



Don't take chances if you wanting to do a L/S swap into your truck. Pull axles and do a spline count first.