3.07 to 2.47 gear swap 300sd 100/k
 

its now a week since the swap here are some of the differences.

--smoother shifts ...no more surges
--drop of 700 rpm at 75 mph
--cruising at 75 with engine purring at apprx 2600
--first tank at 34 mpg up from 29( note the 29 was with ugly motor noise entering cabin.)
--no real big time loss in pick up only half a step slower, but still rocks at highway passing speeds.
--discovered that i had wind noise at 75 for the first time.

rock on diesel geek he did original swap

robert bullard

geek swap
 

fun! i am not surprised at the mileage. if you can tolerate the liesurely take off the increase in mileage is a great thing. i cant think of any negatives in terms of wear, etc.

.............grrrrrr..............and to think that I garnered a 2.88 at a very good price to put in the SD. With all the kudos regarding the 2.47, I might have to start looking all over again. The 3.07 has certainly got to go.

BTW, can you answer a question regarding R&R of the diff?

There is a mounting cap screw with a wide head on the aft side that secures the diff to the subframe. The cap screw appears to take a T-50 Torx bit. However, on the SDL, I immediately rounded the screw because it is made of some cheap material that cannot take any torque.

Any advice on this fastener? How to remove it? Factory replacement??

yikes!
 

probably rusty, making id of the shape difficult. i am thinking if it rounded it right out that you may have guessed wrong as to what to insert into the business end to turn it. i have never removed a rear end myself (except on my '62 190b 30 years ago... that cured me.. although it was a tremendous amount of work, it worked out ok... and i believe that it was a higher gear, too). my shop charged me about $300 i believe, so it must have been a bout 4.5 hrs. of course they have alift and all the power tools.

Actually it was in quite good condition and it could easily be ascertained that it was not a hex socket. The Torx fit the fastener quite well but the fastener would not take the torque. It might have been possible that the T-50 was too small, but, it fit almost perfectly. But, my experience with Torx is limited, so, it is definitely possible that I made an error there. :o

torx
 

i think that they have to be very tight and almost have to be driven in with a hammer, so it is possible it wasnt in all the way either.

do you know where i can get a compression adapter for the 350?

Yep, that is very likely. The bit fit quite easily. Maybe I need a bigger bit.
Hopefully someone who has removed this fastener knows what it is.

Can't you use the glow plug holes??

comp tool
 

i suppose yes on the glow holes. still need an adaptor for the comp guage. also arent some almost inaccessible wo removing the intake?

I thought you had a gauge for the 3.0 L and needed an adaptor for the 3.5 because of a different sized injector?? In this case, I was thinking that the glow plug openings would be the same. In any case, for sure, you would need to remove the manifold to get at the glow plugs for performing the test on the 603. Clearly not as easy as the injectors. I would think that you need to contact the manufacturer of the guage for the proper adaptor.

adaptor
 

we have a fitting for the injector opening on a 123 bodied 240/300 injector. it looks like the kit you referenced me probably would do the trick but it looks like an entire set for all diesels ever made (almost). $130 isnt cheap but probably a fair price if one needed all that. i amhoping for an adaptor for the injector.

I do building work. Torx fasteners can be deceptive in that way. You want it to be a little fat for the hole... Even it fits perfectly try the next size up and if it still fits that's the one you want...
Can't help you with the size on that particular bolt.

2.47 rear swap..LOL speedo mess
 

good news is i got my 380 SE speedo that matches my 2.47 gearing....bad news i just picked up the 380's odometer mileage..up to 260 from my 160 kilometers .....:(

PS no real loss of pick up

robert bullard

That's great! You can say it has 260k and runs like it only has 160k!

Brian, I had the EXACT same problem when I R&Red the axles on my SDL. The Torx fastner you describe was fused in place and removal with the proper tool wasn't an option. To get the bolt out, I had to take a Sawzall and cut away the metal part of the big washer that the bolt seats against and then use a pipe wrench on the now-exposed head of the bolt. I had to replace the bonded rubber/steel washer thingy becasue it was destroyed in this process. I couldn't see any reason to ever dork around with a socket-head bolt again so I used a cut-off saw and removed the head from a Toyota engine head bolt I had lying around. The bolt head had a nice little washer-like surface just under the flats for the wrench which made a sweet place to neatly weld the Toyota bolt head to the old socket-head bolt. I used a normal 14mm socket to install and tighten and, if I ever have to take it apart again, I'll be able to remove that bolt without having to attack it with a sawzall!!!!! See drawing below...

I attempted to remove this bolt in order to change the rubber/metal bushings, numbers 20 and 23 on the diagram. I had previously ordered these items and figured I would do it when I was under there doing the differential mount.

I have contemplated the situation, since I stripped it, and now am pondering whether that fastener is a 12 point metric socket head and not a Torx.
I have purchased a good set of 12 point metric bits (Lisle) and may again attempt to remove this bolt this weekend. There may still be some material left, deeper into the fastener, whereby the 12 point bit would grip.

It just seems that it stripped too easy. The tool could not have been correct. A proper tool should not have stripped it. In retrospect, I can't imagine M/B using a Torx in this application.