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#1
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Transmission flares on upshift from 2nd to 3rd gear
Anyone have ideas of why the tranny on my '87 300D would flare only during the upshift between 2nd and 3rd gear? I hope it's an inexpensive fix because it wasn't that long ago I had the tranny rebuilt.
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1987 Mercedes 300D ~200K (Greasecar & Biodiesel) 1993 Ford F-250 7.3 IDI diesel 165K (Biodiesel) 1996 Thomas/International Bus with DT466 engine |
#2
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Too much vacuum is the typical cause. Put a mity vac in line with the vacuum line from the VCV and modulator and see what vacuum levels you get at various accelerator positions. A simple test would also be to remove the vacuum line going to the modulator. The shifts shuold become stiff or harsh with no vacuum to the modulator.
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1977 300d 70k--sold 08 1985 300TD 185k+ 1984 307d 126k--sold 8/03 1985 409d 65k--sold 06 1984 300SD 315k--daughter's car 1979 300SD 122k--sold 2/11 1999 Fuso FG Expedition Camper 1993 GMC Sierra 6.5 TD 4x4 1982 Bluebird Wanderlodge CAT 3208--Sold 2/13 |
#3
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When is the last time you changed the fluid and filter? That is always a good place to start with trans issues. Also a bottle of Trans-X can help when you refill the system. It will clean the varnish off any parts that have build-up and can help the situation too.
I'm not too familiar with the 124's, but shouldn't too much vac cause all shift points to flare? I would suggest the K2 spring. I has a pretty good flare in the trans on my 123 wagon, which I cured with a new K2 spring kit.
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Andrew '04 Jetta TDI Wagon '82 300TD ~ Winnie ~ Sold '77 300D ~ Sold
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#4
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Having flaring or the opposite (hard shifts) in one transition (2 - 3) but not another is pretty common. People often go to kits to change components in the transmission.
At various times while trying to get my w124 transmission to function correctly I have encountered this. I considered getting a shift kit but kept on trying to get everything right with the transmission. Now my transmission shifts incredibly well. I've never driven a 300D that shifts as smoothly. The steps are straight-forward: 1. Vacuum must be right. Remove all extraneous components, replace bad tubing/connectors, clean out your over-pressure relay & then mity-vac everything. Make sure your VCV is set-up correctly. Make sure your vacuum amplifier (blur flying saucer) is set-up correctly. 2. Transmission pressure must be correct and vacuum modulator for the transmission must be correct. 3. All linkages must be set correctly. With light throttle pressure you can easily be in 3rd by ~23 MPH and 4th by ~30 MPH. |
#5
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The K2 spring kit is a common problem/solution, and I believe it is around $15 dealer, easy to change with the pan off.
Don't let it continue, it will wear out the friction material.
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Gone to the dark side - Jeff |
#6
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Thanks for the replies everyone. As it turns out I'm going to need to get this fixed quickly and will not have time to mess around with it myself, so will take it to the shop. I'll print out your suggestions and leave them with the mechanic - maybe it'll give him ideas that will save time and save me money!
The shift from 2nd to 3rd was always a little funky even right after the rebuild (the previous mechanic will not be touching my transmission again), so I'm hoping it's just a simple mechanical adjustment. I've been driving very carefully and trying to avoid the flare. If I am accellerating lightly it is less likely to flare than if I'm accellerating normally or heavily. In some situations it's impossible to avoid, like having to accellerate up a hill from a dead stop. That's the worst. I'll try to remember to bring closure to this post after the car is fixed and let you all know what the problem turned out to be. Thanks again! Dan
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1987 Mercedes 300D ~200K (Greasecar & Biodiesel) 1993 Ford F-250 7.3 IDI diesel 165K (Biodiesel) 1996 Thomas/International Bus with DT466 engine |
#7
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If your other shifts are okay, a new K2 spring assembly will most likely solve your problem. If you suggest that to the shop and they don't know what you are talking about, you are at the wrong shop.
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#8
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You can also check out this spring kit. It contains the K1 as well as others. It also gives you the options of stiffening/softening the shifts as well by using different k factor springs.
http://www.superior-transmission.com/Product_Page.cfm?ID=19 I have one to put in my one 300SD, it has 2-3, and 3-4 flaring without vacuum.
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Cruise Control not working? Send me PM or email (jamesdean59@gmail.com). I might be able to help out. Check here for compatibility, diagnostics, and availability! (4/11/2020: Hi Everyone! I am still taking orders and replying to emails/PMs/etc, I appreciate your patience in these crazy times. Stay safe and healthy!) 82 300SD 145k 89 420SEL 210k 89 560SEL 118k 90 300SE 262k RIP 5/25/2010 90 560SEL 154k 91 300D 2.5 Turbo. 241k 93 190E 3.0 235k 93 300E 195k |
#9
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Resolution... for now...
As promised, I'm checking back to report on the resolution to the tranny problem. Turns out it was a vacuum leak at the transmission. I just spoke with the garage on the phone and they said something about a "vacuum cap" I think? They also made a few adjustments. One thing I didn't mention earlier (because I hadn't noticed it) is that there was also a slight flare between 3 and 4. I noticed this on my way to the garage. They said the car is shifting "much better" now, but the 3-4 flare still occurs periodically, and was "unfortunately something inside the transmission". Say what?! They seemed to leave it that I should just drive the car until the 3-4 shift gets worse. Hmmm... I think I'll try a different mechanic if the 3-4 shift gets bad enough to really bother me. I'll mention the "K722A-D Shift Correction Package" and see what their reaction is. Unfortunately, the better garages seem to all have these customer relations guys who aren't really mechanics, and say things like "I don't know what you're talking about, but I'm sure the mechanic knows about it..." C'mon man, I'm paying nearly $100 an hour, I want my 10 minutes with the main man, just like at the doctor's office!
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1987 Mercedes 300D ~200K (Greasecar & Biodiesel) 1993 Ford F-250 7.3 IDI diesel 165K (Biodiesel) 1996 Thomas/International Bus with DT466 engine |
#10
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Did you try the Trans-X ?
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1980 240d , chain elongation, cam marks reference: http://www.peachparts.com/shopforum/showthread.php?threadid=10414 http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html evap fin cleaning: http://www.peachparts.com/shopforum/showthread.php?t=156207&highlight=evaporator A/C thread http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html |
#11
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Quote:
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Charles 1983 300D, bought new, 215k+ miles, donated to Purple Hearts veterans charity but I have parts for sale: http://www.peachparts.com/shopforum/showthread.php?t=296386 |
#12
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A vacuum leak and flaring is an unusual combination. There has to be more to the story.
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#13
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I agree. Leaks cause hard shifting. Too much vac causes flares.
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Andrew '04 Jetta TDI Wagon '82 300TD ~ Winnie ~ Sold '77 300D ~ Sold
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#14
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I haven't had time to try anything myself, and I might consider the Trans-X, but it just seems unlikely to me that the transmission is in need of internal cleaning, since it probably has less than 5,000 miles on the rebuild. Would it really get gummed up that fast? The guy at the garage said they couldn't see anything that would be causing the flare, so they attribute it to an "internal" problem. One thing for sure, I have no faith in the guy that did the rebuild. Took him 3 tries to get it even close to "right". I had to cut my losses with him and move on.
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1987 Mercedes 300D ~200K (Greasecar & Biodiesel) 1993 Ford F-250 7.3 IDI diesel 165K (Biodiesel) 1996 Thomas/International Bus with DT466 engine |
#15
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Quote:
I suggested it because any varnish buildup has the potential for messing up the shifting since the speed of the clamping of the clutches in the trans are controlled by hydraulic pressure... so ' flaring' which I assume to be slipping can be the result of slow application of the transmission clutches.. Trans-X simply dissolves varnish... it is not some magic snake oil.... and it has saved me some big money on several cars since I first used it in 1975. IT is relatively cheap to try it... if it does not fix it then it is a no harm no foul situation and you move on to check other potential causes....
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1980 240d , chain elongation, cam marks reference: http://www.peachparts.com/shopforum/showthread.php?threadid=10414 http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html evap fin cleaning: http://www.peachparts.com/shopforum/showthread.php?t=156207&highlight=evaporator A/C thread http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html |
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