Project “Polar Bear”: 1989 V2500 Suburban

[Larry]

You just hit on why I want to use this transmission. I'm building both my '70 K5 and '87 FJ60 for expo travel, and one of them will be taken cross-country. If I'm lucky, I'll even get to go to the North shore of Alaska and maybe through Canada, so I need something that's better on gas than 13 MPG. With a 6L80's 4:1 first gear, I can run a higher gear ratio than what I could normally get away with. Even better if I go with an Atlas TC instead of a circle-pattern NP205.

Right now, I'm just trying to figure out what engine to put ahead of it. I'm keeping the stock 1/2 ton axles, though I'll likely upgrade the axle shafts. I want something as powerful as possible, but also economical and not so much I have to worry about breaking something. For a long time, I was wanting to use a 6.0 with 6.2 heads, but now that I think about it, the 500 HP range is probably a little too risky for a Dana 44/12 bolt. I'm light on the throttle, but BFE is a bad place to have an accident.

Figured that was the case. The deep 1st gear sounds really appealing in theory but in the real world it can be rather annoying. It is humorous where a UPS truck with a 16,000 lbs. GVWR and a little L20 4.8L (without torque management) running a 4.78 axle gear ratio on 245/19.5 tires can chip the tires from a dead stop mainly because the trans has such a deep 1st gear. Even have seen some broken rear axle shafts on the Meritor MS113 axle from the lowend torque of the little 4.8L mated to a 6L90. The down side is, it is also a jerky ride anytime you are in first gear like a slow rolling stop then reaccelerate, etc. The deep first gear is neck jerking and annoying! It is almost like riding in an old truck launching in granny gear all the time. They may have gone too deep with 1st gear IMHO…..nothing that some bigger tires can't fix though. LOL Outside of that the 6L80 and 6L90 are great!

 

[Redpim1]

Congrats on the little one my boy has been the best thing in my life for the last 17 years.
Love all of your rigs keep it up.. One of these days when the Dodge body falls apart around my Cummins I plan to swap the bed engine trans and rear axle into a 80-91 K30 CC 4x4 body... Like i have told all of my friends i didn't buy a Dodge i bought a Cummins. All in good time.

 

[chilliwak]

I am just curious Larry. Has anyone mated one of these transmisions to a 4x4 transfercase? If so what model trucks are they in and what is the motor hp. and torque?:Wow1:

 

[Ridge Runner]

I'm not Larry, but from what I've seen, the later H2s, '09+ Silverados, and '07+ full size SUVs. The biggest engine I've seen it behind is the 6.2 in trucks and Camaros/Corvettes. I'm not up on my sports cars anymore, but I don't think the Z06 comes in an automatic still, else it would be behind the LS7.

 

[Larry]

Congrats on the little one my boy has been the best thing in my life for the last 17 years.
Love all of your rigs keep it up.. One of these days when the Dodge body falls apart around my Cummins I plan to swap the bed engine trans and rear axle into a 80-91 K30 CC 4x4 body... Like i have told all of my friends i didn't buy a Dodge i bought a Cummins. All in good time.

Thanks!

I am just curious Larry. Has anyone mated one of these transmisions to a 4x4 transfercase? If so what model trucks are they in and what is the motor hp. and torque?:Wow1:

Well, GM uses these 6L*0 transmissions across the board from a Tahoe to a Silverado HD 4x4 truck. The new 6L*0 6 speed 4x4 transmission housings still have the same SAE 6 bolt transfercase mount that has been an industry standard for the last 28 years so I don't see why any SAE 6 bolt transfercase from 1985 or newer wouldn't bolt on to one of these. Spline count may be the issue though as I have not heard the size of the output shaft and the spline count it uses.

I'm not Larry, but from what I've seen, the later H2s, '09+ Silverados, and '07+ full size SUVs. The biggest engine I've seen it behind is the 6.2 in trucks and Camaros/Corvettes. I'm not up on my sports cars anymore, but I don't think the Z06 comes in an automatic still, else it would be behind the LS7.

Not sure where this fits in, but you're correct. The biggest engine in front of the 6L*0 transmissions currently is the 6.2L or maybe even the 7.0L in the Vette but I am sure it could handle a much bigger engine. Like I mentioned above, my company uses the 6L90 in commercial step-vans up to 16,000 lb GVWR and the limiting GVWR factor is the park pawl....not the trans internals. Any GVWR above 16K gets an Allison 1000 or 2200 up through the 25,999 GVWR range. We use the L96 6.0L gas engine in trucks of that size instead of the 4.8L.

 

[Ridge Runner]

Well, GM uses these 6L*0 transmissions across the board from a Tahoe to a Silverado HD 4x4 truck. The new 6L*0 6 speed 4x4 transmission housings still have the same SAE 6 bolt transfercase mount that has been an industry standard for the last 28 years so I don't see why any SAE 6 bolt transfercase from 1985 or newer wouldn't bolt on to one of these. Spline count may be the issue though as I have not heard the size of the output shaft and the spline count it uses.

I spoke to Vic at Advance Adapters last year about it. He said that the '85+ NP205s would work, so from what I understand, the 6L*0 is just the standard circle pattern, 32 spline output.

Speaking of "6L*0," what's the difference in application between the 80 and 90? I haven't been able to find anything saying which vehicle or engine the 80s and 90s are mated with. For the most part, they seem to be universally referred to as 6L80.

Not sure where this fits in, but you're correct.

Sorry, that was my way of addressing chilliwak's question about 4x4 applications and engine power.

 

[Larry]

I spoke to Vic at Advance Adapters last year about it. He said that the '85+ NP205s would work, so from what I understand, the 6L*0 is just the standard circle pattern, 32 spline output.

Speaking of "6L*0," what's the difference in application between the 80 and 90? I haven't been able to find anything saying which vehicle or engine the 80s and 90s are mated with. For the most part, they seem to be universally referred to as 6L80

Yeah, that wouldn’t surprise me that GM kept the same 32 spline and output shaft diameter.

There quite a few differences between the 80 and 90 with respect to clutch material, clutch count and mainshaft size acourding to our GM Powertrain contact. Here are a few other specs listed on GM Powertrain’s website. Their website also shows vehicle usage for each. The 90 is used in heavier applications

6L80 option code MYC
- Max GVWR 8,600 lbs
- Maximum engine power: 469 bhp
- Maximum engine torque: 439 lb-ft
- Maximum gearbox torque: 664 lb-ft
- 259mm & 300mm Torque Converter
- Transmission weight: 258 & 300mm converter 258mm: Wet: 207 & 211lb

6L90 option code MYD
- Max GVWR 16,000 lbs
- Maximum engine power: 452 bhp, Diesel: 300bhp – Truck / 555 bhp: Passenger car
- Maximum engine torque: 531 lb-ft, Diesel: 520 lb-ft – Truck / 550 lb-ft: Passenger car
- Maximum gearbox torque: 885 lb-ft
- 300mm Torque Converter
- Transmission weight: w/ 300mm converter Wet: 240lb estimated

 

[gmcpimpin]

Not sure where this fits in, but you’re correct. The biggest engine in front of the 6L*0 transmissions currently is the 6.2L or maybe even the 7.0L in the Vette

I believe the 6L90E comes behind the duramax in the vans.

 

[Larry]

I believe the 6L90E comes behind the duramax in the vans.

Yep, that is correct. Express/Savanna are the only two Dirtymax applications that don’t use Allisons.

Back on topic with the Polar Bear. The ole bear finally got treated to a set of 4:56 cogs in the rear axle to match the 4:56 TruTrac’d front Dana 44 I installed in June that was a left over axle after the K10 received a front Dana 60 last fall.

Man, what a difference 4:56 gears make in the old Burb! They just work so well with 315 tires and a NV4500. The beast still needs more power but deeper gears sure helped it in the meantime. Coloradobill and I are planning a one day trip over Medano Pass in a few weeks to check out the fall colors in the mountains. Medano is an easy shake down trail for the old Burb. Should be fun.

After a half days work all I got was one crummy picture of empty axle housing

 

[chilliwak]

Thank you both Larry and RidgeRunner for your info on the 6 speed auto. I go toying around the idea of having a trans like that in one of my rigs. Probably way off the price range so I dont think I can afford it. Still helpfull info. Glad to see the polar bear getting some new gears. Sometimes you are just to busy working to snap any pics. I usually combine the picture taking with the feeling of a cold one making me happy. Sounds like you are going to have a fun trip Larry. Cheers, Chilli...

 

[gloriavoxdei]

Can't wait to see the pics from you and Coloradobill's trip over Medano pass. My wife and I did that trip in my old '92 k1500 shortbed when we were dating and it was an awesome trip. I want do that one with my kids next summer. You going to take you're girls with you?

 

[Larry]

Thank you both Larry and RidgeRunner for your info on the 6 speed auto. I go toying around the idea of having a trans like that in one of my rigs. Probably way off the price range so I dont think I can afford it. Still helpfull info. Glad to see the polar bear getting some new gears. Sometimes you are just to busy working to snap any pics. I usually combine the picture taking with the feeling of a cold one making me happy. Sounds like you are going to have a fun trip Larry. Cheers, Chilli...

Thanks Chilli!

Can't wait to see the pics from you and Coloradobill's trip over Medano pass. My wife and I did that trip in my old '92 k1500 shortbed when we were dating and it was an awesome trip. I want do that one with my kids next summer. You going to take you're girls with you?

Me neither! I haven’t had the ole burb off-road yet….ever

Medano is a beautiful day trip trail especially this time of year as the trees change colors. A great place to take kiddos to sled on the sand hills too! Just don't stop and write anything in the sand and post pictures of it here or some people will have a coronary (see this thread)

Last summer we used Medano as a short-cut from the San Luis Valley to Canon City while returning from a Utah trip in the K10. I was surprised to see every water crossing very full of water considering it was so dry last summer. With all the rain we’ve had lately it could be interesting over there right now.

Not sure if the ladies are going to come along on this day trip or not. Momma isn’t showing much interest but her parents and my neighbor will probably ride with me. I need to get some cargo tie downs installed in the back of the burb and wire up some power so I can borrow the National Luna fridge out of the K10 for the day.

This was one of the 13 water crossings from summer 2012 over Medano. The trail is simple Subaru type trail

 

[huntsonora]

Just don't stop and write anything in the sand and post pictures of it here or some people will have a coronary (see this thread)

Be sure to write Dales name in the sand and post a pic

 

[Ridge Runner]

Just don't stop and write anything in the sand and post pictures of it here or some people will have a coronary (see this thread)

Wow... To paraphrase Robin Williams from Good Morning Vietnam, that man is in dire need of a blow job.

BTW, I find if funny that you brought over an eye-rolling smiley from CK5.

 

[Larry]

Wow... To paraphrase Robin Williams from Good Morning Vietnam, that man is in dire need of a blow job.

BTW, I find if funny that you brought over an eye-rolling smiley from CK5.

Hehe.. Yeah, I like to use the CK5 smiles as the ones Expo offers are pretty boring.

Is new car pictured a '14 SS or Impala? Rwd or Fwd?

The car in the picture is a 2014 Impala, which is still FWD. It has the new DI 3.6L that really hauls some butt :sombrero:. We’re hoping ours will be here by November. The SS sedan is nice too but not available yet and GM wants way too much money for it.

This is pretty much the same car we have on order. Our Tahoe Z71 in the For Sale Section.