4T60E interchangeability

[Jrs3800]

That's too bad...

Guess I'll just toss it with the trans then.

PM me... We'll talk about it... I have a 96 Trans in the shed that needs a Diff...

[spoiledred94]

Thanks for the offer alec_b.

Guess I'll be on the phone this afternoon finding where all the wrecked 91-95 H body cars are. I am thinking that any 91-95 4T60-E (or HD) with an RPO code of FW2 will have the right 3.06 diff..

[spoiledred94]

I found a 3.06 at LKQ salvage. spent two and a half hours trying to pull the diff. I will go back first thing in the am, I hope hope that It will still be there. The car was 94 I think Olds 88, the spare cover laying in the trunk had the FW2 RPO code. There was no way to know what the mileage is on the trans as it's a digital odometer. I figured it was better to go with this car rather than the 93 bonney with the FW2 code as well because it had 212K on it.

I have everything off but I can't quite get the axle out all the way. I pulled the wheel hub and that bought me a few inches. It feels real loose. I think I just need a bit more room behind the axle (toward the hub) to get it out. Can you tell me how far the splined end is after I start to see splines? For that matter how much total axle fits into diff? I am going to read the manuals again. I hope there's something in there I am over looking.

[alec_b]

You need to take the strut bolts out and pull the spindle forward. There won't be enough room without.

[spoiledred94]

I was tring to avoid that. I see I shouldn't have. I had the right tools, I just didn't use them. Hey thank you again Alec. You are really nice. Should I read the manual or keep sipping at my Bud?

[spoiledred94]

I apologize for the back to back posts. I need to be out to wreckers at 9 ish.

Exactly which gears make up the difference between an 3.06 diff and a 2.97 diff?

Or between a 3.06 and a 2.84 diff? I don't know how deep I have to go into the salvage 3.06 diff gear set to get all the hardware I need to convert my 2.97 to a 3.06.

I have the FSM exploded diagram so I would know what you mean by names or location.

My thought today was that it's all the gears that come out when you pull the control shaft c-clip.

[alec_b]

I just sent JR's a 3.06 diff, all he asked for was the diff itself, all the gears, and the sun gear. That should be all you need, plus possibly the diff cover.

[Jrs3800]

Yeah that newer diff should work for the Trans I have on the bench...

All of the pars that are needed are the Diff and the gear within the diff.. You might just as well take the diff cover too... It could come in handy one day..

[spoiledred94]

So you are saying you don't need the Sun Gear shaft to convert? I didn't pull that at the yard.

Here's what I pulled from the 94 Olds 88 with the FW2 RPO code

[Jrs3800]

The parking gear and thrust washer you could have done without... The sun gear you did need..

That Diff looks to be in pretty good shape.. I also should have told you to get the EPROM chip as well from the PCM..

being that you have a 94 and pulled from a 94 the EPROM on that olds should have worked for you..

Almost forgot... Count the Teeth on the sun gear... Being that it should be a 3.06 you will have 34 Teeth... If thats the case send it here

[spoiledred94]

The parking gear and thrust washer you could have done without... The sun gear you did need..

That Diff looks to be in pretty good shape.. I also should have told you to get the EPROM chip as well from the PCM..

being that you have a 94 and pulled from a 94 the EPROM on that olds should have worked for you..

Almost forgot... Count the Teeth on the sun gear... Being that it should be a 3.06 you will have 34 Teeth... If thats the case send it here

I'll send it to you for retail price . It does have the 34 tooth sun gear.

I think I'll run back out there to grab that EPROM. It's great that you filled me in there. I'll get a new performance burn down the road in May after I have a better handle what to ask for from Ryan.

I can't be more anymore happy with you guys. You make the impossible a done deal.

Pulling and swapping the trans will be nothing compared to this ( )

[spoiledred94]

I have the transmission and, I hope, all the parts, tools and supplies at the work site. I'll begin tomorrow morning and hope to be done by Wednesday, Do I need loctite and / or antiseize compound? I was thinking of doing a post run of pics at different stages, but that may be a waste of time because I may be in over my most of the time. Limited PC access at the site too.

[dirtracr95]

You do realize that putting in that 3.06 diff is going to downgrade you to 2.72 right?

There are 5 diffs for the 4t60e
2.84
3.05*
3.06
3.29*
3.33

* = fine pitch tooth

There are also 3 selections for the drive and driven sprockets all are interchangeable
37/33
35/35
33/37 (rare mostly came in transmissions hooked up to the quad 4, i have a set that I am going to mate up with my 3.33 diff for some 3.73 action)

Your 2.97 is set up with a 3.33 diff with 37/33 sprockets
Your goal of 3.06 is done with 3.06 diff and 35/35 sprockets

[spoiledred94]

I don't think so. The diff itself is a 3.06 as indicated by the FW2 RPO code from the donor car (94 Olds 88). The new used HD trans has a 35/35 drive and driven so the FDR will be 3.06. How did you come up with the 2.72 FDR?

[dirtracr95]

If your swapping the 3.06 diff in a trans that was a 2.97(3.33 diff) it would have the 37/33 sprockets. With the 3.06 diff and those sprockets you get 2.72

[spoiledred94]

3.33 would be almost insane with the SC 3800... But it may be fun as well.. Being that you have a 96 you will have a 3.29 ratio if you went with the 35 Drive and 35 Driven gears..

The 2.84 and 3.06 both use the 35/35 gear set

The 2.97 uses the 37 / 33 gearset which overdrives the 3.33 diff for an overall 2.97 or in your case a 2.93... So yes if you went to a 35/35 gear set you would have a 3.29 ratio as your diff will be driven like Bill stated at 1:1 meaning you have a 3.29 diff that simply overdriven to be a 2.93

I think this is where I got the 35/35 figure for 3.06's

[dirtracr95]

ok are you swapping transmissions or diffs? Because from what i understand it sounds like you wanna put a 3.06 diff in a 2.97 trans


I think this is whats confusing me

Or between a 3.06 and a 2.84 diff? I don't know how deep I have to go into the salvage 3.06 diff gear set to get all the hardware I need to convert my 2.97 to a 3.06.

[spoiledred94]

I can see your logic dirtracr95, thanks for catching that. The gear ratio aspect has been the toughest thing for me to understand and your info looks backed up by the others. So it is too late to go hunting for another diff.

So I have two routes the way I see it:

I can leave the HD 2.97 FDR trans intact. If I go this way I'll have to get another chip to drive the car.

or I can try swapping out the drive and driven and chain gearset to get my 35/35 and use the 3.06 diff that I pulled at the junkyard. I already have the chip for this configuration.

I don't have time to look into procedure tonight. I don't mean to sound naive, but I could do it. The pics in Jrs3800 post on his trans projects made it looked doable to me.

Anyway, it's real late. Goodnight

[spoiledred94]

...I don't have time to look into procedure tonight. I don't mean to sound naive, but I could do it. The pics in Jrs3800 post on his trans projects made it looked doable to me.

Anyway, it's real late. Goodnight

I think I am naive, I could NOT replace those sprockets my own.

Though I do have a transmission to experiment with when I take out the original. Maybe I'll open the case according to procedures to see how hard it would be to pull and replace the sprockets in the HD.

[alec_b]

It's really not that bad to do the sprockets. I haven't done one on a 4t60-e, but I did it on my old 440-T4 (4t60 hydraulic), and once you get the valve body out of the way and organized, there isn't much to it. The 4th gear clutch is right under neath, then bam gears and chain. Slide on, slide off. As long as you take pictures, mark things, and I highly recommend having a ATSG transmission manual or equiv. because the pictures to reference the check ball locations and wiring routing are a lifesaver, no matter how careful you are.