Later model overdrive transmission for P30?

[ClydesdaleKevin]

Anyone know if there was a transmission made for the 454 that had an overdrive that would be a direct replacement for a 1989? 

Now that the rig is running so much better, that extra gear would be nice.

Was there a similar year or later model transmission that would just drop right in with little modification that had an overdrive?  I wouldn't be opposed to having to shorted the front driveshaft...but were all the later model ones electronically controlled?  And if so, is there a controller you can get to make them work without a computer onboard?

Really getting curious and starting to research this now...even thinking about a gear vendor unit...but for half the cost of a gear vendor I imagine I can get a rebuilt transmission if I can find the right one.

Thanks!

Kev

[circleD]

A 4L80E is a 3/4 - 1 ton tranny with O/D but has a computer controller. I thought about doing this years ago with an old truck. My advise is if you go this route and get one out of a junkyard, buy the whole truck so you get all harness hook ups and sensors plus other components can cross over then sell the rest. I have a gear vendor but tried to get info from company with no response to see about maintainance. Becareful when buying used stuff and "I know you will" study what parts and adapters belong with it. Good luck.

[Froggy1936]

Hi Kev The 4L80E is what i put in mine With all the harnesses and control unit & speedometer And TB injection . There is one Not sure of designation but its a 4 speed w OD and Lock up TQ and no computor around early 90,s i think Ill look up the model tomorrow  This would be a bolt in unit But would probably require Drive shaft work  I pait $75.00 to have my frt shaft shortened 3 in and rebalanced .I would also check on using a late model Allison 6 speed  Frank

[Rickf1985]

Frank, The designation you are looking for is the 700R4. It was a light duty transmission that originally had a bad reputation for breaking but there have been major changes and massive aftermarket support for that transmission and I have no doubt it could be set up to work in our units. I have one at home that was slated for another project but I am seriously thinking about putting it in the MH now. All that said, there are stand alone computers for the 4l80 just for conversions like this so either way............


Rick

[cncsparky]

I'm planning a 4L80E upgrade in the future, already have a core tranny scoped out.  These are electronic controlled.  Looking at a couple of different options for controllers that are more DIY and less costly.

http://mattw.dyndns.org/4L80E/
http://www.msgpio.com/manuals/mshift/index.html

There are also a couple of ready to go standalone controllers, one made by TCI. They are $$.

[Froggy1936]

No . The 700 R4 was never used in anything heavier than pick up trucks and vans I dont think it would hold up to a 12000 lb + veh even with the upgrades The sun shell was a very weak spot . I thought there was a 4L80 that was not electronic but cant seem to find it now  There are aftermarket control units for the 4L80E but they are expensive . i??   PS. I love my set up now First MPG Test was 10.2 @ 60 MPH  with many stops and a few 80 MPH bursts necc to get around obsticles (trucks running 55MPH)  Pulling back into traffic takes full throttle after stops along TP  Frank

[legomybago]

I would shop around for a complete Gear Vendors Over/Under drive unit installed in a P30 thats being parted out. The 80's high liners mostly had them...still hard to find though. Probably run you 1,000 or more, but you'll have all the adapters and etc, just need to shorten your driveshaft.

[cncsparky]

Frank, I haven't heard of a non electronic 4L80E.  There were diesel trucks made in the early 90's that used a standalone type controller for that tranny, but info on these is scarce.   

[circleD]

Just an FYI about the Allison transmissions. The ones in the Gen 1 duramaxs had issues with the 1st and reverse gears going out and the flywheels cracking. I thought it was because people were trying out the new diesels and playing around but they weren't. Also the Gen 1 duramax had major problems so I got rid of mine. I thought about putting a diesel in mine in the future. The size specs are close but just an idea.

[bluebird]

Although I've never had a 4l80 trans apart, I have had several 700r4 trannys apart. I'd never consider putting one in a motor home. They just won't hold up. The trans that is in my 95 is huge compared to a 700r4. Don't know about a box to control the tranny, but you will also need a speedo, and those are also controlled from the vss converter. The 4l80 has 2 reluctor  generators, one in front and one on the output of the tranny, the vss module changes the ac volts to dc volts that reports to the pcm, and speedo. The pcm knows how much the tranny is slipping ect by the voltage difference, and can set the service engine light. If you are going to go this route, as has been mentioned, you need the complete system. A donor wrecked MH would be ideal, but it's going to be a lot of work. Gear vendors would probably be cheaper and a lot less work in the long run.

[pvoth1111]

workhorse....engine and tranny.....transplant....or just HD truck transplant....
replacing chevy components is so easy....
In the long run I think the best way to keep these "ol Girls" on the road is a total upgrade of the engine and the trans.....more power, more reliability, more performance, more economy....with a laptop computer and software you could change how the drive train functions on the fly.....hills....long straight roads etc.

the junk yards are full of wrecked trucks with low mile power trains just waiting to help make your next over the road experience trouble free....

[ClydesdaleKevin]

Thanks guys.  Certainly something to consider in the future! 

Kev

[Rickf1985]

workhorse....engine and tranny.....transplant....or just HD truck transplant....
replacing chevy components is so easy....
In the long run I think the best way to keep these "ol Girls" on the road is a total upgrade of the engine and the trans.....more power, more reliability, more performance, more economy....with a laptop computer and software you could change how the drive train functions on the fly.....hills....long straight roads etc.

the junk yards are full of wrecked trucks with low mile power trains just waiting to help make your next over the road experience trouble free....

You mean there is still a junkyard that sells parts out there? All the ones on the east coast are just crushing everything and selling the scrap, they make more money easier and faster that way.

[pvoth1111]

ebay

http://www.ebay.com/itm/8-1-LITER-VORTEC-L18-DROPOUT-ENGINE-MOTOR-CHEVY-GMC-120K-COMPLETE-DROP-OUT-/201001733314?pt=Motors_Car_Truck_Parts_Accessories&hash=item2ecca30cc2&vxp=mtr

[pvoth1111]

ebay

transmissions....cheap.......the 2nd one out of a motorhome....probably a bolt in....has e=break and all

http://www.ebay.com/itm/01-02-Chevy-Silverado-GMC-Sierra-8-1L-4x2-Automatic-Transmission-Allison-1000-/190988382005?pt=Motors_Car_Truck_Parts_Accessories&hash=item2c77cb6f35&vxp=mtr


http://www.ebay.com/itm/02-Southwind-Motorhome-8-1-workhorse-P30-Allison-1000-Automatic-Transmission-/170983346948?pt=Motors_Car_Truck_Parts_Accessories&hash=item27cf66d304&vxp=mtr

[Froggy1936]

Searching for Electronicly controlled trans I found this info @ Novak Conversions site       Engine Compatibility
While the 4L80 is generally mechanically compatible with Chevrolet style GM engines, it does require a transmission controller. That controller may be the factory-integrated with the PCM as on 1991-1999 TBI & Gen II engines, with the 1999-2007 Gen III engines, or the 2007+ Gen IV engines. Or, the controller can be an external GM or aftermarket unit designed for earlier engines.
It should be noted here that Gen IV style 4L80's do not mix and match well, as they have an integrated Transmission Control Module and require a CAN bus network signal to an appropriately matched engine combination  Frank

[Froggy1936]

So besides Expensive after market controlers there are other options I beleve it is saying that Any earlier 4 speed auto w OD computor can be used (700r4) Also stated was the trans needs a 7 position shifter (though i am using my old floor shifter wich only has 6 positions) I cannot select manual low only . all the rest is the same And the only shifters i could find for the 4L80E were sticks like the old trucks from the 30,s For the drag racers. This trans is highly reccomended for veh up to 8000 Lbs and the 4L85E up to 16000LBs The veh i took mine out of was rated @ 11000 Gross So i am not worried about overloading it Though i weigh in @12000 As is And i have updated the sprag & 2nd brake band for better torque application   Frank P.S. they also mentioned (the reason i was confused) That since all GM trans are electronicly controlled The E is not always used

[Froggy1936]

The Turbo Shop has a few answers also That eliminate speedo change And also hookups for carbuerators ! Frank  The Turbo Shop has an outfit that comes with a custom cast-aluminum tailshaft  housing with a mechanical speedo drive and the option of several different trans  mounts for various applications. The Turbo Shop also uses the simple and  relatively inexpensive GM diesel computer and a custom wiring harness to operate  the trans.   Roughly 75 percent of the 4L80EÂ's internal parts are interchangeable with a  TH400, and the bellhousing bolt pattern and flexplate are the same as the 400,  so it bolts up to big- or small-blocks just like normal. In a carbureted  application, the only other concession to the computer  is a throttle-position sensor (TPS) mounted to the carburetor, which is included  in Art CarrÂ's and The Turbo ShopÂ's kits.

Read more: http://www.hotrod.com/techarticles/drivetrain/gm_4l80e_automatic_transmission_review/#ixzz2odGH6KhR