Question : 4t65e-HD diff in a 60E case

[3400-95-Modified]

Is this a possible swap? if using the output shaft, inner CV's, diff extension cover, and diff??

Or will the 65e diff extension cover not fit the 60e case?

[gpse3400]

It should. I belilve that the differential is longer so the HD cover should work.

[IsaacHayes]

Hmmm. So does that mean Jon if you do that you could use a full length W body axle on that side if you were doing the F body brakes? Still might not be the right length but would have the same ends on each side you need. Hmm.

[3400-95-Modified]

this is what I'm thinking, I may need one on the other side because i would need to use the output shaft... Hopefully its the same length.

See now I thought this but I was told it wont work on the Bonneville club forum, But what makes no sense to that is a 60e and 65e diff are the same... the HD is obviously larger and you can do a 65eHD upgrade to a 65e case... so um yeah why cant I do that to mine

I'll look into this more when I can get to the yard and get the parts needed.

This will open the window up to a Intense LSD for the 65e-HD... I'm not quite ready to drop $500 thou, so I'll get my EP and use it as long as it will last... and keep this on the back burner if the 60e diff takes a dive

[Crazy K]

I just heard of doing this myself. I'm trying to learn more too.

I have a friend who just did it in a 98 GS, and a comment was made that GM did the same on the 92-96 supercharged G and H body trannys... which were 4t60e's!

[3400-95-Modified]

I'm gonna visit the yard next week sometime and pull some parts, and then I'll be testing this in my core trans thats outside.

[Crazy K]

I came up with an important detail:

1994 PONTIAC BONNEVILLE SE 3.8L
A-1 CARDONE Part # 601060 {Overall Length=24 3/8" Outboard Splines=33 Inboard Splines=34 Inboard Joint Type=Male} Right
A-1 CARDONE Part # 601210 {Overall Length=20 3/4" Outboard Splines=33 Inboard Splines=35 Inboard Joint Type=Female} Left

1994 PONTIAC BONNEVILLE SE 3.8L supercharged
A-1 CARDONE Part # 601092 {Overall Length=24 7/8" Outboard Splines=33 Inboard Splines=34 Inboard Joint Type=Male} Right
A-1 CARDONE Part # 601199 {Overall Length=21 5/16" Outboard Splines=33 Inboard Splines=35 Inboard Joint Type=Female} Left

right difference: 1/2 inch
left difference: 11/16 inch
but the same spline counts.

the CV shafts are different!

[3400-95-Modified]

yes I'm aware of this, custom axles or frankenstein axles are in order if I do this but I will already have outer N-body CV's from my coming brake upgrade so doing more mods isn't a big deal.

[Crazy K]

I read and ran though an tranny info chart.

the heavy duty 4t65e differential is 3.29 ratio diff.

the current FDR of either tranny I would be servicing would be 3.43 or 3.33 (3.1, 3100, or 3.4 W bodies)

[3400-95-Modified]

yes you would need a 96+ transmission to do this too... Unfortunatly, or at least 96+ final drive ring and low roller sprag parts in there... the final drive ring is the same for all diff ratios, but 94 95 and 96 are all different cuts and direction.

I'm using a 3.05 diff right now so if I were to go HD, I would jump to a 3.69 final drive.

[Crazy K]

ah!!!!

After a bit of research... if the 92-96 supercharged H bodies got a heavy duty differential, they did not get the one put into later supercharged cars.

As for the correct car that I know this diff swap was done on:

1998 BUICK REGAL GS 3.8L Supercharged
A-1 CARDONE Part # 601256 {Overall Length=24 9/16" Outboard Splines=33 Inboard Splines=39 Inboard Joint Type=Male} Right
A-1 CARDONE Part # 601255 {Overall Length=21 7/8" Outboard Splines=33 Inboard Splines=34 Inboard Joint Type=Female} Left

1998 BUICK REGAL GS 3.8L Supercharged
A-1 CARDONE Part # 601250 {Overall Length=24 3/4" Outboard Splines=33 Inboard Splines=34 Inboard Joint Type=Male} Right
A-1 CARDONE Part # 601255 {Overall Length=21 7/8" Outboard Splines=33 Inboard Splines=34 Inboard Joint Type=Female} Left

On this car the left axles are the same
the right have a different spline count, and a difference of 3/16 inch.

both the na and supercharged trannys had the same diff ratio, but one diff was heavy duty and one wasn't. additionally, they do have differing chain ratios and thus differeing FDRs.

AND... the right axle spline count differs between this 98 and the 94 posted earlier, so definitly a different diff.

AND...... since the 94 does have different axle lengths, it's probable that there may be a heavy duty diff in that car.

[3400-95-Modified]

I was going to be shooing for 96+ stuff since thats what I have, so Rather than looking at a bunch of different part numbers and spline counts and all that crap, I was going to just go get all the diff parts and axles and output shafts and figure out what fits into a 60e case with the 96 final drive ring... Much easier that way if you ask me.

BUT EP's machined plate version of his LSD is in route to me now so I think I will be all set in that department for a while now.

[TurboGTU]

MY 65-e and 60-e diff covers were the same. If you'r ring gear is different than the 65 hd diff gears, you'll need to get the ring gear too. After that the passenger cv axle.

[3400-95-Modified]

65HD diff cover is longer than the 65e's I know that, and also as you noted the ring gear can differ, but all 96+ are the same for all ratio's so that only applies to older 60e transmissions and when you mix and match new ring gears to old trans you need to use the correct roller sprag right behind it too, since the oil holes are slightly different.

[Crazy K]

but all 96+ are the same for all ratio's

I think you are incorrect, only some are the new ratio:

http://home.att.net/~subzero350/1996_4T60-E.pdf

http://home.att.net/~subzero350/1996_4T60-E.pdf

vs

http://home.att.net/~subzero350/1998_4T65-E.pdf

* 2.86, 3.05 and 3.29 ratios are "fine pitch" final drives. Sun gears, internal ring gears, and pinion gears are NOT interchangeable with other final drives