Buy used or rebuild transmission? what say ye?

[leadphut]

i have a '94 e420 that runs great until it shifts from 1st to 2nd (mechanic assumes 2nd is bad, because i have 4th gear - i.e. car is not starting in 2nd and skipping 3rd). scenario - the car takes off as expected from the line, but once it hits its shift mark, it feels as if it skips 2nd and goes to 3rd.


taking it into my mechanic tomorrow to see what the issue is. the car has 153k on the clock, is a solid 7, out of 10. with that being said, would you:


- rebuild the transmission if needed ~ $3k
- roll the dice for a used unit
- part out car


affording the rebuild is not an issue. just curious what others suggest.


thank you,
Troy

 

[Maui]

I think it depends on how much you like the car and how long you intend to keep it. You don't see a lot E420's around, so if it's a nice car that you enjoy driving I would vote for the rebuild.

 

[gsxr]

Skipping 2nd gear may not require a replacement transmission. Have you started with the basics? Verify control pressure cable operation / adjustment, and confirmed the kickdown solenoid is not engaged? Not to mention proper fluid and fluid level, etc.

Trans replacement is usually after losing reverse, losing all forward gears, or some other major failure. Of course, it may be difficult finding a shop willing to spend the time to properly diagnose your issue, instead of throwing one big $2k part at the problem...

 

[Stevester 500E]

If you find a low mileage good working transmission, I would chance a used one.But as GSXR says, get a proper diagnosis first.

 

[Klink]

Everything GSXR said up there. Check simple basic things first. Most especially, look for a kickdown switch that is stuck closed and/or a shift gate "B" position switch that is broken or inadvertently been put into the "B" position. Losing second gear is not a common failure mode in that transmission.

 

[leadphut]

Picture of said offender.

Thanks for the replies. I'm taking the car to a specialist tomorrow morning, who is familiar with these cars and their transmissions. He mentioned the "second band" may be out, but would know from driving and inspecting. Just wanted to go into the inspection with half-an-idea of what to do.

Fingers-crossed. I'll update mañana.

 

[SG-Motorsports]

That looks like a nice E420. I agree with Klink, not a common failure for a 722.3 to lose 2nd gear. Bands are extremely rare to delaminate and have instant failure, more likely the outer apply piston seal is leaking or valve body is clogged with debris. Always a good idea to double check the basics first though.

I see you're in Portland, I'm near Seattle. I have a good used trans I took out of a customer's 1994 E420 about 8 years ago. She was a good customer and I had installed new reverse clutches and all side seals and resealed the front pump about 10k miles before she was rear ended. I bought the car for salvage, parted it and saved the trans because I knew it was a good unit (or at least it was 8 years ago), but don't have any plans for it. It's yours for $1000 if you want, but I'm not gonna deal with shipping it...too messy.

Good luck with your repairs, hopefully it will be something simple.

 

[leadphut]

so the verdict is, reverse is going out and second gear is gone. good news is, second gear has to come out to get to the reverse bands so it's "fate?" dunno

quoted me $1500 to complete, with the possibility of having to fix something else.


@SG-Motorsports:
thank you for your offer. if you were willing to ship i think we could do business together. otherwise, my hectic life wouldn't allow me time to get up north to see you. it's too bad really, because it seems as if it would be a win-win scenario.


i cannot get the car into the shop until after the 4th, so i won't have much to update until then.

 

[gsxr]

Uh - I thought it was the other way around, you can change the reverse clutches just by pulling the pump, but second gear stuff likely requires more disassembly? I've never rebuilt a transmission so I'm not positive. If you have any work done, I'd get a full rebuild, not a half rebuild.

BTW - you never really explained how the trans was "skipping" 2nd gear. Do you mean it was flaring (engine revs up between shifts, like it hit neutral) from 1 to 3? Or is it shifting ok from 1 to 3 but just 'missing' 2nd gear?

 

[leadphut]

shifting occurs as if it skips 2nd entirely. the shift from 1st happens around 3k rpm and shifts straight into 3rd. if it touches 2nd, it's not noticeable. no drama, no over-revving, no thunks or noise.

regarding the disassembly process, i could have it backwards. as he was telling me some possible solutions, i was mentally moving funds around to cover the expense. i probably even glazed over at the moment. i have been socking money away for suspension and rims. there's also some nice sportline seats, front and rear, that caught my eye.

must...not...give...in...to...temptation.

 

[gsxr]

What you describe sounds suspiciously like the kickdown solenoid is energized when it shouldn't be, as Klink mentioned back in post #5. Quick test - unplug the solenoid from the tranny (single wire at rear of passenger side, just pull it out) and go for a test drive. You'll need to jack up the car a bit at the front/right to slide underneath and pull the wire off.

 

[samiam44]

Reverse needs addressing too... I would definitely repair the car and not part it out.

 

[gsxr]

Oh yeah, forgot to ask - when you put the car in reverse, how long of a delay is there until reverse gear engages? (Time it with a stopwatch, or watch with a second hand.) Also, is there any clicking noises when backing the car up?

 

[leadphut]

thank you for the heads-up regarding the kickdown solenoid. i've a lift at home, so that'll make things easier. i'll get under it tonight and follow your suggestions. after the solenoid is unplugged and i'm driving, should the transmission shift into 2nd iff the solenoid is bad?

time for reverse to take affect is ~1-2 seconds. i'll pay closer attention and report back this evening. no clicking or noises while backing up; however, there is a small "clunk" from the rear, once torque is sent from the transmission.

last weekend i put the car on the lift and spotted wettness (seepage) from the differential, but everything else appeared "in order."

 

[gsxr]

1-2 second delay into reverse is pretty normal on a high-mileage tranny. 3-4 seconds is the early warning that the reverse clutches are worn. At 6-10 seconds, failure is coming sooner rather than later.

Clicking noises while backing up are another sign of imminent failure; sounds to me like your reverse may be OK (at least acceptable) given the mileage.

Definitely curious to hear what happens, if anything, when the kickdown solenoid is unplugged!

 

[leadphut]

Out in the shop, not knowing if this is the switch or not. Can't seem to find a picture online.

 

[SG-Motorsports]

Yes, that is the switch Dave is referring to, just unplug the single wire and test drive. Though I don't think that's your problem because it wouldn't skip 2nd gear, it would rev to near red-line, then slam into 2nd gear unless you lifted off throttle, then it would dump back into lower gear.

Losing 2nd gear entirely is a very strange problem, not something I've ever seen before in my 24 years of dealership experience working on these cars. The good news is, it should be obvious during tear down what the problem is. If it isn't obvious, I would be very suspect of the valve body.

Either way, If they quoted you $1500 and you are confident in their abilities, I think you're making a good decision having them fix it. Good luck...

 

[leadphut]

thank you.

so i unplugged it, went for for a drive without any perceivable difference. beats me.


as far as my confidence in the transmission shop goes, it's entirely through my mechanic. my mechanic is sharp, so i'm indirectly trusting the tranny shop.


that's it for today. hate to end it on bad news, but oh well. it's what toys do.


thanks for all the help guys!

 

[Klink]

Actually, the kickdown solenoid engaged when the control pressure/throttle cable is not at full throttle and/or with the lever not down in position 2 makes them goofy as hell, and one of the things they like to do in that condition is go right past second gear. The USA version.034 actually has three easy possibilities that lock on the kickdown solenoid. Those consist of the B position switch and kickdown switch which we have already discussed, and the 1-2 cold upshift delay relay that is controlled by the LH control unit.
But, the salient point that everyone forgets is that the hydraulics in the valve body are not designed in such a way that kickdown soldnoid engagement without the control pressure being at full throttle and/or the shift lever operated control valve being in position 2 results in any kind of logical or "normal" hydraulic control process. It doesn't. It usually produces bizzarre symptoms very similar to what he is describing. You DON'T simply get normal shift sequencing and behavior but occurring at higher speeds, you get "Holy crap! This transmission is trashed!" kind of behaviors.

If unplugging it didn't work, then yes, you have to look for something worse. Sorry it is proving to be more involved...

 

[gsxr]

But, the salient point that everyone forgets is that the hydraulics in the valve body are not designed in such a way that kickdown soldnoid engagement without the control pressure being at full throttle and/or the shift lever operated control valve being in position 2 results in any kind of logical or "normal" hydraulic control process. It doesn't. It usually produces bizzarre symptoms very similar to what he is describing. You DON'T simply get normal shift sequencing and behavior but occurring at higher speeds, you get "Holy crap! This transmission is trashed!" kind of behaviors.

If unplugging it didn't work, then yes, you have to look for something worse. Sorry it is proving to be more involved...

Ditto what Klink said: ^^^

I had something similar happen on one of my cars and it took me a while to figure it out. I had thought the kickdown solenoid was basically separate from control pressure (Bowden cable) but nope, the valve body expects to see the two signals match, or it does weeeeeird stuff. Another, very unlikely, possibility is the kickdown solenoid itself binding in the engaged position. I would be really, really surprised if that was the case but it's much more of a nuisance to test as you'd need to swap it out.

 

[leadphut]

Update:
after receiving an estimate of ~$3k for a rebuild, i decided to see if i could locate a used transmission. happened to find a "recycler" in the area that found a "low mileage (90k ish miles)" transmission for $875. another $800 for install with new rear main seal for the engine, new fluid and filter for the tranny. so i went the used route. seems apropo with the car's value; i.e. it's an e420.


thoughts?

 

[nocfn]

3k is very high for the rebuild IMO. BTW you should also do complete flex disk replacement, carrier and trannny mount too so be sure that is included in the pricing.

 

[leadphut]

too late. RnR has been performed. grrrr.

 

[nocfn]

I was suggesting that as the labor is the same since it all has to come apart to swap in a new transmission. Hopefully if they noticed anything wrong they changed them. When I did mine they did the front flex but not the rear or the carrier. I paid for parts but not for labor when I read the bill after the fact and they installed for me on the C126.

 

[gsxr]

If it's not too late... for that used 90k-ish tranny, re-seal it on the workbench BEFORE installing!! It will cost probably under $40 for new OE/dealer seals/gaskets and it will prevent leaks. The external covers are easy to do... vac modulator, governor, kickdown solenoid, dipstick tube, Bowden cable, selector shaft seal, B1/B2 covers. The B1 needs a special tool, or creative clamping, as it's under a lot of spring pressure. The others are not. Ideally you'd do the front pump O-ring but that's a minor can of worms and requires the special tool kit. If there's any sign of leakage there, do it now. I'd consider the converter seal even if you skip the pump O-ring.

Otherwise, plan on seeing red (literally, on the garage floor) in the near future after the swap.

 

[leadphut]

If it's not too late... for that used 90k-ish tranny, re-seal it on the workbench BEFORE installing!! It will cost probably under $40 for new OE/dealer seals/gaskets and it will prevent leaks. The external covers are easy to do... vac modulator, governor, kickdown solenoid, dipstick tube, Bowden cable, selector shaft seal, B1/B2 covers. The B1 needs a special tool, or creative clamping, as it's under a lot of spring pressure. The others are not. Ideally you'd do the front pump O-ring but that's a minor can of worms and requires the special tool kit. If there's any sign of leakage there, do it now. I'd consider the converter seal even if you skip the pump O-ring.

Otherwise, plan on seeing red (literally, on the garage floor) in the near future after the swap.

mechanic assured me the tranny would be "serviced" before install, which included much of what you listed. i'll put it on the lift and take some pics next week.

 

[gsxr]

OK - if the mechanic is really doing a proper re-seal, that is fantastic.

 

[Tiger Core]

I had to get the transmission on my 400E built in 2012. Transwerk did a good job and I've covered about 22,000 miles on it no problems. I'm selling the whole car for a fraction of the price you were quoted to get your trans done. Just a thought...

 

[leadphut]

I had to get the transmission on my 400E built in 2012. Transwerk did a good job and I've covered about 22,000 miles on it no problems. I'm selling the whole car for a fraction of the price you were quoted to get your trans done. Just a thought...

do you have any details of your said car? pics and price would be most excellent.

 

[leadphut]

gave a quick wash on sunday. trying to rekindle our flame together.

 

[M104-AMG]

Give a call to Sun Valley a call. $1,700 for a reman with 2-year warranty is awesome. I've used them twice.

neil

http://mercedesdismantlers.com/Mercedes Transmission Price List.htm

 

[leadphut]

Give a call to Sun Valley a call. $1,700 for a reman with 2-year warranty is awesome. I've used them twice.

neil

http://mercedesdismantlers.com/Mercedes Transmission Price List.htm

thanks, but the work has already been completed.

for now i'm just trying to fall in love again. i'm fickle. i'm playing with the idea of new rims and suspension pieces. wouldn't mind a tastefully, slight drop. we'll see.

 

[Tiger Core]

http://www.500eboard.com/forums/showthread.php?t=10030

 

[leadphut]

http://www.500eboard.com/forums/showthread.php?t=10030

looks well worth the asking price.

GLWS!