CampStewart
Observer
When they do it in person do they put it on a dyno? Because of the engine tune and torque management delete was there any concern about the trans handling all the mods?
GMT400 vs GMT800 Suburban
- Thread starter CRolandLJ
- Start date
When they do it in person do they put it on a dyno? Because of the engine tune and torque management delete was there any concern about the trans handling all the mods?
jeep-N-montero
Expedition Leader
No dyno when mine was done.
No concern for the trans its the 4l85e which is a beefed up 4l80e. It would take more than 500lbs or so to blow it up. The 4l80/5 trannys are essentially a computer controlled th400 with overdrive. The internals are identical with the addition of a seperate planetary and clutches for the OD. The 4l80/5 also has a lockup converter which the th400 doesnt. Th400s and 4l80s have been built for over 2000hp and gobs of torque. The 4l80s are a HD trans designed to keep the rpms up between shifts to keep the engine power up specifically for towing a load. 400hp and 500ftlbs is no issue for a 4l80. Especially one that isnt going to be abused every weekend at the drag strip
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jeep-N-montero
Expedition Leader
Part of me is glad they didn't put the Allison in the Yukon/Burb with the 8.1, they eat up more power and can't tune the trans the way you can with the 80/85. I'm still on the fence about looking for a clean 8.1, but I'll see how the 6.0 feels after the BBP tune, it would be very difficult to find another Yukon as clean as our 03 that we bought from the original owners with 126k miles.
CampStewart
Observer
If you get the 6.0 tuned please post up the results. I had a 454 in my 99 and am curious as to if the tune in a 6.0 gets it anywhere near that.
jeep-N-montero
Expedition Leader
Funny you mention that, I almost bought a white 99 7.4 before I came across our 03 Yukon.
Martinjmpr
Wiffleball Batter
From what I can see on CL, GMT-400 2500 Suburbans are the best "sleeper" deal out there. Buy one for $3k, spend maybe another $3k or so in maintenance and repairs and you'd have a rock solid vehicle that would last as long as you'd likely want to keep it.
As a bonus, the interior on the GMT-400 seems bigger since it has more room floor-to-ceiling than the GMT-800 burb with its higher floor.
As a bonus, the interior on the GMT-400 seems bigger since it has more room floor-to-ceiling than the GMT-800 burb with its higher floor.
Bojak
Adventurer
I agree with most all of this except size. GMT 800 is bigger inside and out in my opinion. Inside, it felt bigger but not substantially or much. Outside, much bigger. My 2000 GMC 2500 ccsb had a 6inch suspension lift and 35's. My 2006 GMC 2500 ccsb had 4inch suspension lift and 35's. With 2 inches less lift it was taller and wider.
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jeep-N-montero
Expedition Leader
Agreed!
I gotta disagree on size also. My buddy has a nice clean 98 k2500 burb and it definately seems smaller inside and out. We had them parked side by side and the 800 is bigger. We havent broke out the tapes yet but even he commented on the difference.
Martinjmpr
Wiffleball Batter
Measure floor-to-ceiling. I'm pretty sure the 400's are taller because they don't have the spare tire under the body and the deck is lower.
jeep-N-montero
Expedition Leader
Here is a clean 99 burb with the 454 https://www.ksl.com/auto/listing/5273695?ad_cid=9
That seems clean and a good price. Utah is far though. Thanks for the link. I'm about a week away from selling my DD so the search will start in earnest then. I bet he finds a buyer before then.
According to specs, cargo box height for both gmt 400 & 800 is 40.5". Ill measure mine when I get home from work to verify. The floor may be higher on an 800 but so is the roof.