I'm getting ready to attempt the 5 speed conversion on my 87 190D 2.5 turbo. The links on the forum describing this process have been very helpful but I still have a few questions regarding compatibility/required parts that need answering before I feel comfortable starting the project.

Here is the scenario: I have my complete '87 190D 2.5 turbo (automatic) and a complete '92 190E 2.6 5 speed donor car ready to go. With the exception of one-time use stretch bolts for the flywheel, do I have everything I need IN HAND to complete this conversion?

I believe the current understanding is that the 190d 2.5 NA 5 speed flywheel is the ideal choice for this conversion because of weight and timing mark, but am unsure if the one from 2.6 will actually work as-is? I also have some confusion regarding single and dual mass flywheels??...

Some additional confusion regarding output shaft/driveshaft diameters and flex disk size. My understanding is that the 2.2D and 2.3 gas cars use the smaller 168mm gearset and a correspondingly smaller diameter driveshaft and flex disk, whereas the 190D 2.5 turbo, 190e 2.3-16 and 190e 2.6 cars use the larger 185mm gearset, and correspondingly larger driveshaft and flex disks. If this is true, then everything I already have at my disposal with the 2.6 donor car is everything I will need...correct???

With respect to diff ratios, my 190dt has the 2.65 and my 190e 2.6 donor car has the 3.27. Am I correct in that with my current 2.65 and with the common 1:1 fourth gear in BOTH the automatic and manual, my rpms at 60 will be identical with either trans in 4th gear (roughly 2,350), but my 5th gear rpms will be 20% lower with the .80 5th gear in the manual (like around 1,880 @ 60 vs. around 2,350 with my auto?)

Further, if my math is correct, with the .80 5th in the donor trans (20% reduction from 1.0 4th gear) and the 3.27 diff from the donor car, my rpms in 5th @ 60 will be approximately 2,320 in 5th with the 3.27 vs. the 2,350 with the auto and 2.65 (or roughly identical top gear rpm as my current auto and 2.65??)

Then, if all these assumptions are correct, the 2.65 diff would provide for the best fuel economy/slowest acceleration; the 3.27 would provide virtually identical power and economy with either the 5 speed or auto, and the best compromise between power and fuel economy would be the 5 speed with a 3.07 diff?? My personal goal is for maximum economy with the sacrifice being a little less performance. With the 2.65 I'd probably just use the 4 gears for around town driving and save the 5th for highway cruising.

Any and all thoughts would be greatly appreciated!

Many thanks,

J. G.

The 3.27 gears will work ok. If you spend most of your time driving around town, and not on long freeway trips/commuting in 5th gear, I'd use the 3.27 diff. The final drive will still be taller than the stock 2.65 diff. And you'll get 10%+ economy improvement just from the manual trans vs auto.

A 3.07 diff would be a decent compromise, IMO... final drive (assuming 0.80 5th) would be 2.46 which would be very good, without sacrificing much either around town or on the freeway.

The 2.65 diff would be bad at both ends. Not only would it be a dog around town (especially with an OM602, not OM603) but the final drive of 2.12 is stupid tall on the freeway. Anything other than flat/level roads and you'd be downshifting. Maybe if you live in Kansas this would be tolerable. But I doubt it.


For the record, my nephew's 124.128 with 717.411 5-sp transmission and 3.27 differential is turning 2000rpm at 57mph, 2500rpm at 72mph, and 3000rpm at 85mph, in 5th gear. With that setup, top gear is unusable until ~55mph. Now imagine what it would be with 3.07 or 2.65 gears....!!!

__________________
Dave
Boise, ID
Check out my website photos, documents, and movies!

Dave,

I was afraid the 2.65 might be too tall...figured I'd get hyper mileage and wouldn't have to change the speedo head either. Probably also wouldn't be good for the clutch trying to engage from a dead stop with a 3.86 first gear and the 2.65 rear. Guess I'll just buy an appropriate speedo for the 3.27 application...

Given I have the 3.27 in hand now, I'll probably go with that for the baseline changeover and see how it is to live with. A diff swap to the 3.07 would be an easy change at a later date. From what you say about your nephew's car running about 2,000 @ 57 mph (and .78 5th gear w/3.27) this is a couple hundred rpm lower than I would have expected...hmmm...I guess this must be the 6.5% larger tire on the 124...

Any input about my questions regarding the proper flywheel or the driveshaft/output shaft flange size?...am I all good with switching over the components from the 2.6 donor car? (I think I only would have run into a problem if my donor car was a 2.3 gasser or 2.2D, right??)

Many thanks!

J.G.

p.s.- I like your website!

Shoot, I can't help with the flywheel or driveshaft questions... I've never done this conversion. My nephew's car was purchased with the 5-speed already installed (it was for sale on this forum a few years ago, in NC). Sorry!!

Dual mass flywheel needs to be used if the transmission is from a car that had it (trans input shaft length is different).

__________________
Hanno
'79 6.9 Sold (after 27 years)
'83 280SL, 5 spd.
'94 E320 Sdn. 5 spd conversion
'02 E320 Sdn.(on loan to mom!)
'87 300E (5 spd. conversion) Sold
'05 E500 Wagon

Hmmm...I don't know if EITHER my 190D 2.5 Turbo or the donor 190E 2.6 had dual mass??? HELP!!!

The 2.6 has the dual mass go ahead and use the transmission and flywheel together from the donor in the 2.5. Don't worry about the 2.5 transmission you are not going to use that transmission or flywheel anymore dual mass flywheels are good for diesel engines because they are heavier I using one in my 300D

I have heard something about the diesel flywheels as having some "timing marks" on them that the gas ones don't..for tach sensor pickup information or something?...If so, would the best solution all around be for me to buy a 5 speed flywheel for the 190D 2.5 NA?

No don't buy a 190D flywheel you don't need it. Just use all the parts from the donor. You can't use a single mass flywheel with your 2.6 transmission 602 engines don't need timing marks on the flywheel for tach to work

Thanks...that helps. So far it is sounding like my donor will supply all the parts I will possibly need...except for one use items like stretch bolts or a clutch disk if the one I have shows too much wear when I disassemble...

Ugh...I think I made a mistake. I had been looking at the W201 differentials used in this attached chart and just realized the 190E 2.6 w/ 3.27 axle and manual 5 speed application is ONLY up to 9/89. My donor car is a 92 which according to this chart has the 3.92's...How is this even possible if MBZ didn't change the trans gear ratios from 9/89, too?? Crap!

If this so, (and the following trans ratios are what I thought- 1st: 3.86, 2nd: 2.18, 3rd: 1.38, 4th: 1.0, 5th: .80) this diff will be useless for my trans swap.

Can anybody enlighten me?...

Attached Thumbnails

 

Clean the back bottom part of your donor differential and you are going to find out what ratio you have

WARNING: That is a European chart. The US-spec cars did NOT always use the same ratios! You will need to check in the USA EPC to figure out what years/models had what differential ratios.

I think your USA-spec 1992 190E-2.6 with manual trans will still have a 3.27 diff. Check what's stamped on the diff housing, that will confirm it. It appears the USA-spec 1992 201.029 with auto trans went to a taller 2.85 ratio.

Thanks...it had occurred to me that there were clearly Euro model only variants on the list, but for some reason I hadn't made the connection and assumed the worst case scenario...I can't get to the car to check today but will confirm numbers on both the diff and trans housing to make certain. Fortunately, I was able to dig a 1992 190 dealer brochure out of my basement and did verify on the technical specifications sheet that the only available diffs were 3.27 for the 5-speed and 2.87 for the auto. Whew...breathe!...really had myself worked up there for a minute! Thanks again for all your help. Will let you know how the transformation progresses.

J.G.

p.s.- found a neat final drive calculator on the internet...its for 4 wheel drive vehicles, but I fudged the numbers where it asks for hi range/low range/3rd range numbers. You can actually input two different driveline variations with different trans/gear ratios and tire sizes and see what the operating differences look like side to side. (I input a calculated ".66" for all three 4WD values to make it work for 2WD vehicles)...the resultant calculations (speeds/rpm) seem to be pretty accurate...

http://www.grimmjeeper.com/gears.html

I've been watching the talk about 190d auto trans to manual trans. I have a pair of 190 cars, an 89 2.6 gas auto, and an 84 d with 220k miles. The 89 is rust free, the 84 is rusted out. I was going to just swap motors and trans to the 89, but the manual trans is calling me.
I also have a 3rd 190d, 37mpg with auto and gentle wife driving.140k. Many issues, most fixed.Ignition switch must be handled very gently.
I recently parted out a 76 240d 4spd manual that went fine, rusted out. 140k miles. I'm sure the trans would work. The flywheel maybe, anyone have a clue?I was going to get a jetta tdi rusted out car and a rust free gasser and do a build, but I do own these cars and a manual trans in one would be nice. And then 1 more thing I started would be done.
I know the engine belhousing area is specific, but the pedal set looks close.
Thanks to all who have contributed to the 190d trans swap thread. Any one need a 240d motor, started right up at 10F. Mid coast maine.