lately i have noticed 4th gear in my 87 300td slips until it is nice and hot. fluid is up to the correct point and is a nice red color. doesn't smell burnt. it will slip even with no vacuum hooked up. the shift itself is kinda soft feeling but i can hold it in 3rd until i get to 50mph, shift to 4th and it feels solid. let off accelerator to give it a better chance then start giving it more fuel. once it hits 2600rpm and the boost builds, the tach will keep climbing far more than normal torque converter slip. i don't let it do this but that's what happens if i try. i am also hearing a whine and i think it's my trans too! there is what sounds like a sad power steering pump that goes with engine rpm and a gear whine that is noticeable 1st gear and 3rd. that is when i notice it most. coasting with the engine brake effect then accelerating will change the tone/ make it go away until you let off. i don't hear it from my diff, but right under my shifter. there is a 74k mile 350sdl at a yard nearby and i think i want to get the transmission to be safe. does the 350 have a lower stall torque converter? (i'd like that) and what about swapping the tail for the speedo output? difficult? besides that and nss wiring differences, is is bolt it? any info is appreciated! thank you!

another note: i have the modulator turned up a little for firmer shifts. i dont like soft slushy shifts. it is fine when hot and 1-3 are fine when cold. it is just 4th when cold that the slipping happens..

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83 300CD- sanden, dual p/f condensers, 160a alternator, ect
91 300TD- 722.6, #22 head, 3.5L IP, w140 manifolds, ect

The 350's redline is ~1000 rpm lower than the 300, so shift points will be too early. Both cars torque converter stall speed is about the same.

-J

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1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

Has anyone played with the shift governors in these? Is that the only issue? I'm running a 350 injection pump and all my power comes at about 3000 rpm so maybe if wouldn't be so bad. It actually accelerates faster without downshifting and revving the crap out of it now. Maybe that's what's killing mine.

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83 300CD- sanden, dual p/f condensers, 160a alternator, ect
91 300TD- 722.6, #22 head, 3.5L IP, w140 manifolds, ect

I plan to get the 350 transmission tomorrow! so everything will be correct besides the electronic speedo output which can be easily swapped over, right? and maybe NSS wiring. but that's no big deal. i just hope it bolts in and have no mounting or drive shaft issues!

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83 300CD- sanden, dual p/f condensers, 160a alternator, ect
91 300TD- 722.6, #22 head, 3.5L IP, w140 manifolds, ect

i read that the 722.3 transmission from the om617's don't have an oil jet for the speedo gear if you're swapping from an electronic one? is this true on these too? that makes me nervous

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83 300CD- sanden, dual p/f condensers, 160a alternator, ect
91 300TD- 722.6, #22 head, 3.5L IP, w140 manifolds, ect

My mechanic told me that the Dextron III heats up differently than the previous Dextrons, so you have to adjust your level accordingly to allow for that.

Interesting. But it hasn't always done this. I think it's just on its way out. I'm hoping this 350 trans will work

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83 300CD- sanden, dual p/f condensers, 160a alternator, ect
91 300TD- 722.6, #22 head, 3.5L IP, w140 manifolds, ect

bump? i'm surprised nobody has any info on these om603 transmissions. here is my concern... on the 722.3 behind the om617, there is an oil supply to the tail section for mechanical speedometer gear lubrication. on the transmissions for electronic speedometer cars, there is no oil passage in the main body of the transmission to the rear section. has anyone taken a w126 om603 electronic speedo transmission apart and have pics to see if this is also true on these later 722.3's? or has anyone swapped a 350/ 300 sdl transmission or drivetrain into their w124 and ran into this? i really would like to know this before buying this 350 trans and finding out i have to rig up some electronic speedometer controller to a v8 w124 speedo head and wind up spending more money on all this than rebuilding my current turd would cost haha! any info on these transmissions is appreciated! even the exact 722.3xxx model number i could look up and find some info that way?

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83 300CD- sanden, dual p/f condensers, 160a alternator, ect
91 300TD- 722.6, #22 head, 3.5L IP, w140 manifolds, ect