sootnsmoke

In the next couple weeks I will be doing the auto trans fluid and filter change. I will be ordering the Genos FSM CD as well for the 91. I plan on doing the front and rear band adjustments and want to see what the FSM process outlines. I read that auto band adjustment are recommended to be done with fluid/filter changes. Is that the case if shifting and shift timing are performing as expected?

I have read a couple posts on fluid/filter changes and band adjustments for the 3 speed automatic here but have seen some contradictory information. First, what is the current recommended fluid for a 91 automatic trans? Not looking for a synthetic fluid or upgraded alternate. I have heard ATF 4, but others have referenced some Dextron variants etc

Recommendations for best sealing trans pan gaskets and quality filter with sources would be great. Years ago when I drove an automatic Chevy TH350 I would always get weeping trans pans after doing filter and filter changes. This seemed to occur even though the stock pan lips were in good shape, the pan bolts were not over tightened and I used a rubber rather than cork gasket. Would like to avoid that and get it sealed up right.

For just a pan drop/drain with filter change on the 91 auto, how many quarts are drained with the stock pan?

Thanks all!

Alan

Onemoparnut

The band adjustments can't hurt. The fluid is supposed to be atf+4. And the best gasket can be bought for under 20 bucks at the dealer. They are a reusable gasket and they work the best.

bobva

You have great intentions with what you are doing.
Problem is your not getting all the old fluid out. Their is still lots of old fluid in the TC lines and cooler the only way to get that out is have a good shop do it.
Or Put a drain plug on pan get yourself 10 GL of fluid in one end out the other.

My self I have a P&J ride its a 67 GS400 this is how i take of her while the trans was being rebuilt I had all the pan bolts hilicoiled (I like changing filters).

Now for the funny one if that car gets 500 to a 1000 mile a year she still get new filter and fluid on her rebirthday.
If i had a auto in my truck Id do the same thing Once a year or 20,000 miles what ever comes first.

The shop charges me 75 bucks.

ellis93

Stop by a trans shop and ask about a hard fiber pan gasket,it won't leak and their cheap.
Fluid needs to be +4,some are using john deere hydro fluid in them and seeing lower trans temps

sootnsmoke

How does their shop process work? Does your shop drop the pan, change filter, AND flush all fluid per their process for $75? Or, is that their charge for just a filter and fluid change? Do they adjust bands as well? What am I missing?

Maybe I will end up using your shop. You are in Granite Falls which is only about 40 minutes or so away from me so your shop can't be too far from me. Let me know your shop name and I will give them a call. thx

bobva

Im very sure he does a complete service after all he is the builder and my brother in law.
Sorry
I do live in granite but the car and my brother are in idaho. I live in the center of the convergence zone. So I keep the car over there 80% of the year, and he does the maintenance.

There are plenty of good to great trany shops here in the P.S. that do a complete for not much more than he does.

If you dont know of any shops there is one shop over in marysville that has a real good reputation and I believe they charge a very fair price.

PM me if you want there name.

Crossy's son

I wouldn't get an old transmission flushed completely. The old clutches rely on some of the metal materials in the fluid. Only time our trans guy uses his flushing machine is when he does a full rebuild.

you should adjust the bands and tweak the valve body- Click this link for a great article on how to do it

https://www.dieseltruckresource.com/...e-t265745.html

bobva

Youre half right.

Flushing (chemical cleaned) will and does leave cleaning agent in trans if not done right. which nobody does. In the end you could get a mix of up to 80% new dextron 20% cleaning with a jiffy lube guy.

Fluid exchange uses no chemicals they pump new Dextron in trans. No you wont get all the old out.

sootnsmoke

Thanks, I gave that thread a read and I will be doing the band adjustment myself with a pan drop/filter replacement. Looks pretty basic. I talked to a transmission tech at a local shop that has been in business since the 1950's. Many long time customers go there time after time. Anyway, he said that if the fluid in your trans is not burnt and has been serviced over time, there is no need to do any flush. At most he said, going further than changing the filter would be to simply disconnect the cooler return line and let the pump push out more fluid into a bucket while idling. He didn't try to upsell anything further, just an honest response. I think sometimes we have a tendency to go overboard to try and do more than the machinery actually requires to last a long time.

1cowboy

I don't mean to but in but I need some from some of u cummins genius I have a 2001 cummins rolled it recently but has a bran new tranny in it along with a new clutch a 6 speed that is my old 93 cummins is running great except for the auto tranny is toast can I put the 6 speed from the 01 in my 93 without to much trouble or would I be ahead just to get a beefed up auto in my 93!!!

Douglas2

I have one of those, and I hate to admit it but I'd really like the '93 OD set up for the second truck my wife would be driving...she is not a fan of the big manual for some reason...
cheers,
Douglas

1cowboy

How hard was it to put in what were the extras u had to put in to it