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+--- Thread: Trans Upgrades for an 85 300d? (/showthread.php?tid=4602)
Trans Upgrades for an 85 300d? - 85-300D - 05-24-2013
Just wondering what auto trans upgrades are available for my 85 300d. Are there many options. I am thinking of trying to make some power with it, but am unfamiliar with this trans and what can be done with it. Thanks.
Mike
RE: Trans Upgrades for an 85 300d? - SurfRodder - 05-24-2013
lots of upgrades... the same basic trans is used in higher HP cars... but you are unlikely to need anything special for a stock OM617 and even a fairly upgraded 617 likley wouldn't overpower a fresh rebuilt trans done by a competent shop...but while theyre in there... I understand the urge to overdo it!
RE: Trans Upgrades for an 85 300d? - 85-300D - 05-24-2013
Thanks for the reply. I am thinking of trying to squeeze some power out of the 617 - just not sure how crazy I want to get yet. The past two diesel trucks I have owned have been 609hp, and 670hp, at the wheels. Where is a good source for the good trans parts?
RE: Trans Upgrades for an 85 300d? - Simpler=Better - 05-24-2013
You can get a shift kit, there is info over on PP.
For manuals, there is the 240D 4spd, the impossible euro 5spd, or swap in a BMW getrag, toyota supra, gm whatever, etc. box with an adapter plate.
RE: Trans Upgrades for an 85 300d? - raysorenson - 05-24-2013
The '85 already has a higher stall T.C. than the other w123's. I think the shift kit is called "superior". There are adapter plates out there for the 617 that open up a lot of other options.
RE: Trans Upgrades for an 85 300d? - 85-300D - 05-24-2013
Will the shift kit allow for much more power capacity? What upgrades will hold roughly 250hp at the wheels? I am guessing some sort of performance t.c, clutches, separator plates, shift kit/valve body, ...?
RE: Trans Upgrades for an 85 300d? - larsalan - 05-24-2013
I think at that point you'll also be talking about converting the driveshaft's flex disks to some beefier metal part or change to a u-joint setup.
Or take your chances. But, we've all seen them rubber discs blow out and a driveshaft whipping up into the chassis.
cue the flex disc upgrade linkz...
RE: Trans Upgrades for an 85 300d? - 85-300D - 05-28-2013
Yeah, flex disc upgrade info would also be helpful. What exact model of trans is this anyway?
RE: Trans Upgrades for an 85 300d? - SurfRodder - 05-29-2013
(05-28-2013, 07:39 PM)85-300D What exact model of trans is this anyway?
pretty sure its a 722.3 someone else will either corroborate or correct that...
RE: Trans Upgrades for an 85 300d? - raysorenson - 05-29-2013
I think the Californica '85 cars had different transmissions than the '85 federal cars.
RE: Trans Upgrades for an 85 300d? - DeliveryValve - 05-29-2013
'85 Cali has the 722.416 trans. '85 Feds got the 722.303 for the 300sd and 722.315 for the 300d.
RE: Trans Upgrades for an 85 300d? - 85-300D - 05-29-2013
I did a search for upgrades for the "722.315" and couldn't come up with anything...
RE: Trans Upgrades for an 85 300d? - raysorenson - 05-31-2013
http://www.superior-transmission.com/Product_Page.cfm?ID=19
RE: Trans Upgrades for an 85 300d? - 85-300D - 05-31-2013
Thanks for the link. It looks like that kit corrects some shifting issues with the stock trans. Are there any parts that will allow the transmission to hold additional power?
RE: Trans Upgrades for an 85 300d? - raysorenson - 05-31-2013
I take "firm" shifts to mean more pressure applying the friction bands/clutches, which means more torque capacity, so this will be a performance upgrade. I recommend against doing anything to soften 2nd gear on an '85 trans. MB already fixed the harsh 1-2 shift issues on the '85. If anything, you'll want to firm it up.
RE: Trans Upgrades for an 85 300d? - SurfRodder - 06-04-2013
generally the firmer the shift, the better it is on the trans as well...
RE: Trans Upgrades for an 85 300d? - Simpler=Better - 06-05-2013
From what I've read, increase the modulator pressure if you're getting slippage. This is done from outside the transmission with a gauge pretty easily. I don't know what long term impacts this will have, but it should fix slippage.
FWIW I always ran my transmission with 0" vacuum (various reasons). I always just let off as it started to shift. If I kept flooring it i would get the classic bangshift
RE: Trans Upgrades for an 85 300d? - SurfRodder - 06-05-2013
Slip = heat and sloppy shifts
Excessive heat = trans damage