Buying 300sd Bad Transmission
 

Hi. I am buying a 300sd from my friend's neighbor.

It is a 1983 300SD with 117k documented miles.

He is selling b/c when the trans gets hot "slips in every gear"

I was considering taking the trans from 85 300sd (for sale) that was recently rebuilt, but I understand that the transmissions are different.

Before purchasing the new vehicle I'd like to know people's experiences and what I can expect to pay for a rebuild if necessary...in looking at threads I see $1,200 to $2,500 for a rebuild. I'd also like to avoid the rebuld if possible.

Thanks for your guidance.

David

The 85 is different from the other years internally. The torque convertor and shift points etc are different. However it should bolt right up to the SD. Just get all the vacuum stuff from the 85 to go with the tranny. You will have to mix and match to get it to work right, but it should not be to tough of a job.

300sd Transmission
 

Thank you diesel giant.

My next question is can I then put the 83 trans in my 85 in case I don't part it? The 85 is a great running car but the body has rust. I am thinking maybe sell the 85 and rebuild the 83 trans. 2 running cars should be worth more than 1 running car!

Anyone interested in the a 1985 300sd 302k and over $4k in recepits?

Physically the tranny will bolt in and out of both cars. The controls will need to be tweaked a little, but you could theroitically get either to work in either car.

300sd Transmission
 

Thanks diesel giant!

Please try this first
 

Pour a liter of TRans-X in your transmission. Don't over fill :eek:

Use a gauge and set your modulator pressure by using the little key in the modulator. DON'T LOSE IT. It's not hard and the exact procedure can be found in the search feature. With low pressure the trans can slip, flare, overheat, and cause premature wear on the bands and drive clutches.

After driving it 20 to 100 miles, drain the fluid and replace the filter. Drain the converter also.

You should know within 10 miles if your adjustment fixed your problem.

Let us know, eh?

little key
 

where is the modulator... is it on top of the
fuel distrubtor.... what little key..
anyone have a picture...

preasure
 

what should the preasure be....

Selling 85 300sd - Fixing 83 300sd
 

Thanks for your ideas guys. I am going to try to work with the trans of the 83, and not swap out the transmissions.

So I have listed my 85 300sd on the for sale forum. 302k over 4k in repair receipts. Best offer over $2100 gets it.

Thanks for the advice and I will advise you when I get to work on the 83's tranny.

-David

hell yes try and fix that tranny it might be a simple thing that can be fixed in the car. good advice and good luck!:)

My sd was totaled 2 weeks ago and i am looking for a replacement,lets see what i get for it from insurance.

The modulator is on the drivers side of the trans and has a vacuum line leading to it. The key is located in the center of the module under the rubber cover. Turning it clockwise increases the pressure. You should check specs for your year trans and you can set it at idle. 42 to 52 pounds is the range but a specific psi setting is listed for each trans and modulator model.

David, where I come from, a $2000 rebuild is on the lower end of the scale.
If I could get away with a $2000 rebuild that'd be great! but of course, if you don't HAVE $2000, not saying that I do either, it can be a wallet breaker.

Mine slips in 4th gear..Cruising at 50Km/h when I mash it without hitting the kickdown switch, the engine revs to high hell and I have to manually downshift to get it to grab...I see a potential rebuild on my hands, but I am possibly just crazy enough to attempt it myself..

BTW does anyone know what bands/clutch paks are responsible for the 4th gear?
Is there an ATRA manual somewhere that I can reference in rebuilding this tranny?

$2000 to rebuild a 722? :eek: You have to be kidding, they're not that complex AT ALL. The converter doesn't need to be rebuilt (no lockup clutch), just a flush will do, MAYBE a rebalance. Figure $250-400 to yank the unit itself.

I was going to spend a few Bens to reseal them all (the SDL leaks like crazy) and since they're out I may as well replace the two clutch packs in there behind the pump. They're already out and such. :)

As I recall first, second, and reverse are all using bands, I still have yet to see a band wear out after many, many, many years + miles. I will not replace mine. The "Banner" rebuild kit with paper + rubber and two clutch packs is only around $180 from Bulk-part.com. I can't recall if it's Alto frictions or BW. Either way, they're fine. Figure maybe $100 more for thrust bearings too. Maybe a new TV Cable also.

When rebuilding or just repairing... DON'T forget to grind the rivets off the hub since there is an o-ring hidden in there that is a major source of pressure leakage. :eek: